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Landscape Message: May 5, 2017

May 5, 2017
Issue: 
7

UMass Extension's Landscape Message is an educational newsletter intended to inform and guide Massachusetts Green Industry professionals in the management of our collective landscape. Detailed reports from scouts and Extension specialists on growing conditions, pest activity, and cultural practices for the management of woody ornamentals, trees, and turf are regular features. The following issue has been updated to provide timely management information and the latest regional news and environmental data.

The Landscape Message will be updated weekly April through June. The next message will be available on May 12. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.

To read individual sections of the message, click on the section headings below to expand the content:


Scouting Information by Region

Environmental Data

The following data was collected on or about May 3. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via our instruments for the 2017 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

Region/Location

GDD

Soil Temp
(°F at 4" depth)

Precipitation
(1-Week Gain)

Time/Date of Readings

1-Week Gain

2017 Total

Sun

Shade

Cape Cod

56

117

59

58

0.67

12:00 PM 5/3

Southeast

49

133

62

56

0.72

4:15 PM 5/3

North Shore

47

153

49

46

0.41

10:30 AM 5/3

East

65

186

57

55

0.25

4:30 PM 5/3

Metro West

57.5

157.5

50

48

0.71

6:00 AM 5/3

Central

55

183

54

51

0.29

4:22 PM 5/3

Pioneer Valley

60.5

154.5

56

53

0.89

10:00 AM 5/3

Berkshires

66

140

53

51

0.80

9:15 AM 5/3

AVERAGE

57

153

55

52

0.59

-

n/a = information not available

Drought Conditions Update: Little change from last week... approximately 23% of Massachusetts is currently under official drought status. Virtually all of the area under drought status is classified as 'Abnormally Dry', which is the lowest classification level.  For more information see http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?MA.

Phenology

Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)
PLANT NAME (Botanic/ Common) CAPE S.E. N.S. EAST METRO W. CENT. P.V. BERK.
Spiraea x vanhouttei (Vanhoutte Spirea) Begin * * * Begin/Full * * *
Elaeagnus umbellata (Autumn-olive) * * * * Begin * Begin *
Syringa vulgaris (Common Lilac) Begin Begin/Full Begin Begin/Full Begin Begin Begin Begin
Rhododendron spp. (Early Azaleas) Begin Begin Begin Begin Begin * Begin Begin
Cornus florida (Flowering Dogwood) Begin Full Begin/Full Full Begin Begin Full Begin
Malus spp. (Crabapple) Begin Full Begin Begin/Full Begin Full Full Begin
Cercis canadensis (Redbud) Full Full Begin/Full Full Full Full Full Full
Amelanchier spp. (Shadbush, Serviceberry) Full Full Full/End Full/End Full End End Full/End
Pyrus calleryana (Callery Pear) Full/End Full/End Full/End * Full/End Full/End Full/End *
Chaenomeles speciosa (Common Flowering quince) Full Full Full Begin/Full Full Full Full Full
Magnolia x soulangeana (Saucer Magnolia) Full/End Full/End Full/End Full/End Full/End Full Full/End Full
Rhododendron 'P. J. M.' Full/End Full Full Full/End Full/End Full Full Full
Prunus serrulata (Japanese Flowering Cherry) Full/End Full/End End End End End Full Full
Forsythia x intermedia (Border Forsythia) End Full/End Full/End End Full/End End Full/End Full
Rhododendron mucronulatum (Korean Rhododendron) End Full/End Full/End Full/End Full/End End End Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature over the last week was 56°F with a low of 42° on May 3 and a high of 76° F on April 29. A total of 0.67 inches of precipitation fell, the majority occurring on May 2, but a little on the April 27 & 28. April 27 - 29 were mostly cloudy with near 100% humidity followed by mostly sunny days. Soil moisture is adequate.

Pests/Problems: Gypsy moth eggs began to hatch late last week (4/29) in Sandwich and possibly earlier in some other parts of the Cape. We are expecting significant defoliation this season from gypsy moth. Winter moth continues to feed, 5-6mm larvae can be found in buds and on expanding foliage. Boxwood psyllid, Psylla buxi, can be found feeding on boxwood resulting in cupped leaves. Aphids and rose leafhopper nymphs can be found feeding on rose. Rose leafhopper nymphs can be found on the underside of leaves and cause a stippling damage that is similar to spider mite damage. Cedar apple rust teliohorns were active during periods of high humidity. Botrytis blight, aka tulip fire, was found on many tulips. Botrytis tulipae causes malformations and small lesions on tulip flowers and leaves often coalescing and resulting in blight. Red thread has been very active in lawns over the last week resulting in fast forming brown patches in lawns. Weeds in bloom include garlic mustard (Alliaria petiolata), Mouse-ear cress (Arabadopsis thaliana), Dandelion (Taraxacum officinale), Henbit (Lamium spp.), Speedwell (Veronica spp.), Fig buttercup (Ficaria verna), Mouse-ear chickweed (Cerastium vulgatum), Common violet (Viola papilionacea), Shepard's purse (Capsella bursa-pastoris), and Yellow rocket (Barbarea vulgaris).

Southeast Region (Hanson)

General Conditions: A beautiful and colorful 2017 spring; one of the best in years! The cooler weather, combined with a near-record warm day of 81 degrees on April 29, and sufficient rain, has resulted in an extended and overlapping spring bloom. Leonard Messel Magnolia just ended bloom and Forsythia remains in bloom in some areas and is just ending bloom in others, after two weeks of full bloom! Hanson received 0.72 inches of rain and soils are moist. The crabapple and apple bloom is terrific; best at one site in Hanson in15 years, mostly due to the low number of winter moth caterpillars which have decimated the flowers for so long. The crabapple fragrance is unbelievable and the honeybees are numerous and buzzing.

The following plants are in full bloom: Sassafras albidum, Magnolia ‘Elizabeth’, Malus sp. (Apples & Crabapples), Cornus florida (Flowering dogwood), Cercis canadensis, Kwanzan Cherry, Amelanchier (shadbush), Halesia sp., Prunus serotina (Black Cherry), Rhododendron ‘Olga Mezitt’, PJM Rhododendron, Chaenomeles speciosa (Common Floweringquince), Pieris floribunda (Mountain Pieris), Syringa vulgaris (Common Lilac), Spiraea prunifolia f. simplicifolia (Bridlewreath Spirea), Spiraea thunbergii ‘Ogon’, Azalea ‘April Snow’, Exochorda racemosa (Pearlbush), Rhododendron schlippenbachii (Royal Azalea), Kerria, Viburnum 'Mohawk', Viburnum carlesii (Mayflower Viburnum), Flowering Almond, Exochorda racemosa, Saruma henryi, Epimedium sp., Helleborus foetidus, Glaucidium palmatum, Vinca, Pulmonaria, Trillium, Anemones, Lamium, Primula, Brunnera macrophylla, Ajuga, Lunaria, Erythronium americanum (Trout Lily), Stylophorum diphyllum (Wood Poppy), Aurinia saxatilis (Basket of Gold), Dicentra cucullaria (Dutchman’s Breeches), Dicentra spectabilis (Bleeding Heart), Euphorbia polychroma, Asarum canadense, Phlox subulata, Arisaema sp. (Jack-in-the-pulpit), Lamiastrum galeobdolon, Lunaria annua (honesty or money plant), Mertensia virginica (Virginia bluebells), Violets, grape hyacinths, daffodils and tulips.

The following plants are beginning bloom: Fothergilla major (large Fothergilla), Fothergilla gardenii (dwarf Fothergilla), Vaccinium corymbosum (highbush blueberry), Daphne x burkwoodii 'Carol Mackie', Daphne tangutica, Meserve hybrid hollies, Convallaria majalis (Lily-of-the-valley), Phlox divaricata, Polygonatum sp. (Solomon's Seal), Tiarella cordifolia (Foam Flower) and Galium odoratum (Sweet Woodruff).

Cherry 'Hally Jolivette', Pieris 'Brouwer's Beauty', Pieris japonica, Star magnolia, Pachysandra terminalis, Sanguinaria canadensis ‘Multiplex’ (Double Bloodroot) and Helleborus x hybridus are ending bloom.

With sufficient rain, lawns are greening up nicely and with Forsythia bloom almost at the end, we are the tail end of the window for preemergence crabgrass applications. Also, if using a preventative grub management product that contains chlorantraniliprole (AceleprynTM, GrubExTM), it is best applied before the end of May; follow the directions on the label before applying.

Hummingbirds were observed in Hanson, MA on April 28th and Kingston, MA on May 1st.

Pests/Problems: Winter moth had an extended egg hatch over 2 weeks, ending April 27th, in Hanson. Scouting the landscape in the Hanson area and from reports coming in from Carver, MA, the winter moth caterpillar population appears to be down significantly from previous years. The small green winter moth caterpillars were seen feeding between the tips of leaves they have webbed together in host plants, especially Japanese maples, crabapples, apples, roses, etc. We are seeing 1st, 2nd and 3rd instar, with the majority at 2nd and 3rd instar. Hanson has 469 GDD at Base 40.

In Hingham MA, Gypsy moth began to hatch around April 26 and in Hanson around April 29, and hatch continues in each of those areas. The earlier hatched gypsy moth caterpillars have started to balloon (spin silk and float through the air) and have settled in to feed. However, with the incredible number of gypsy moth caterpillars out there that have just hatched, or are about to hatch, we should see ballooning increase this coming week. The small black caterpillars are covered with tiny hairs which are capable of causing an allergic skin reaction or rash for some people. In past years, many people reported contracting a skin rash after the gypsy moth caterpillars landed on bare skin. Examining oak buds and newly expanded oak leaves revealed both gypsy moth caterpillars and winter moth caterpillars; however, the gypsy moth caterpillars greatly outnumbered the winter moth caterpillars. Gypsy moth caterpillars were also found on blueberry flowers and buds, European beech, maples etc. Winter moth caterpillars and gypsy moth caterpillars are small right now, and damage is not yet significant. However, as the caterpillars feed, they will continue to grow in size. So, continue to monitor host trees and smaller plants, and if these caterpillars are found, manage them while they are small before too much damage is done. (See Tawny Simisky’s Insect section of the Landscape Message).

The recent rain has been beneficial not only for plants but also for the Entomophaga maimaiga fungus that inoculates gypsy moth caterpillars and kills them. We need more rain to continue to encourage the Entomophaga maimaiga fungus to hopefully knock back this substantial 2017 gypsy moth caterpillar population. Lily leaf beetles were observed in Hanson on April 27th. Both males and females are present and egg-laying has started. These bright red beetles are easy to see; manage early to avoid significant damage to true lilies. Continue to monitor hemlocks for hemlock wooly adelgid and also for elongate hemlock scale (Fiorinia externa). Elongate hemlock scale (Fiorinia externa) is also a pest on fir (Abies spp.) and spruce (Picea spp.) https://ag.umass.edu/home-lawn-garden/fact-sheets/elongate-hemlock-scale

Continue to monitor for hard-needled pines for European pine sawfly and manage early if found. Bacillus thuringiensis (Bt) does not work on sawfly larvae.

Monitor pines for pine needle scale: https://ag.umass.edu/landscape/fact-sheets/pine-needle-scale

Continue to monitor spruce, fir, hemlock, arborvitae, etc. for spruce spider mite. The following insects are active: snowball aphids on viburnum, aphids, deer ticks, dog ticks, wasps, carpenter bees, bumblebees, ants, honeybees, solitary bee, boxelder bugs and slugs.

Continue to take precautions for deer ticks, use tick repellents and conduct deer tick checks frequently. Dandelion, veronica, ground ivy, violet, and chickweed are in bloom. The Massachusetts invasive plant, barberry is also in bloom; shear back now to remove the flowers to prevent seed from forming.

North Shore Region (Beverly)

General Conditions: The temperatures during this reporting period were mainly in mid 50s and lower 60s except on April 28 and 29 when temperatures went up into the low 80s. We had rain showers for half of the days during this reporting period with most occuring on May 3. Approximately 0.41 inches of rain were recorded at Long Hill. Because of high temperatures on two days early in the reporting period we gained 47 growing degree days. Gardeners and landscapers are busy doing spring cleanup. Soils are moist and suitable for planting. Woody plants that continue to bloom include: Serviceberry (Amelanchier arborea), Weeping Higan Cherry (Prunus subhirtella), Mountain Pieris (Pieris floribunda), Kwanzan cherry (Prunus serrulata), Star Magnolia (Magnolia stellata), Korean Rhododendron (Rhododendron mucronulatum), Callery Pear (Pyrus calleryana), Allegheny serviceberry (Amelanchier laevis), Flowering Dogwood (Cornus florida), Burkwood viburnum (Viburnum burkwoodii), Large fothergilla (Fothergilla major), Royal azalea (Rhododendron schlippenbachii), Highbush blueberry (Vaccinium corymbosum) and Llilac (Syringa sp.) Spring flowering herbaceous plants seen in full bloom include: Bleeding heart (Dicentra spectabilis), Trout lily (Erythronium americanum), Daffodils (Narcissus spp.), Bloodroot (Sanguianaria canadensis), Crocus (Crocus spp.), Japanese wood poppy (Glaucidium palmatum), Pachysandra (Pachysandra procumbens), Vinca vine(Vinca minor), Forget-me-not(Myosotis sylvatica)and tulips(Tulipa sp).

Pests/Problems: Winter moth caterpillars were observed feeding on maple, apple and crabapple leaves. Brown to tan leaf spots with concentric rings (Volutella fungal blight) was observed on Pachysandra. Prolonged periods of leaf wetness due to rain showers favors this disease on pachysandra. Remove diseased plants and thin the bed. Remove also fallen leaves and other debris that may be inhibiting good air circulation. Apply a fungicide to the plants when the weather is wet. The gelatinous telial horns on orange galls of cedar apple rust are at the end of releasing the spores. Examine fully formed leaves of nearby apples and crabapples regularly for bright yellow-orange spots. Weeds are thriving and some of the weeds starting to bloom or seen in bloom include: Dandelion (Taraxacum officinale), Fig buttercup (Ranunculus ficaria), Ground Ivy (Glechoma hederacea) and Purple Deadnettle (Lamium purpureum).

East Region (Boston)

General Conditions: We ended the month of April with a couple of beautiful warm sunny days in the 80’s, reaching 83°F and 84°F on the 28th and 29th respectively. The month was slightly warmer than normal with an average high of 61.2° F and an average low of 42.9° F. Rainfall for the month totaled 5.66 inches, well above normal. The last week has seen great temperature fluctuations, with highs ranging from 49° F to 84° F and lows ranging from 44° F to 62° F. We have had little precipitation with only two rain events dropping a combined 0.25 inches of rain. Soils remain moist making weeding and planting easy. We have gained 65 GDDs bringing the total accumulation on the year to 186 GDDs. As the forsythia fade, the lilacs are taking over, already putting on a great show of color. Plants in bloom include: Acer palmatum (Japanese maple) and their hybrids, Amelanchier canadensis (shadblow serviceberry), Amelanchier laevis (Allegheny serviceberry), Amelanchier nantucketensis (Nantucket shadbush), Anemone quinquefolia (wood anemone), Elaeagnus angustifolia (Russian olive), Exochorda x macrantha ‘The Bride’ (pearlbush), Fothergilla major (large fothergilla), Halesia tetraptera (Carolina silverbell), Hyacinthoides hispanica (Spanish bluebell), Poncirus trifoliata (trifoliate orange), Prunus kansuensis (Kansu peach), Prunus serrulata 'Kwanzan' (Kwanzan cherry), Quercus variabilis (Oriental oak), Rhododendron schlippenbachii (royal azalea), Rhododendron vaseyi (pinkshell azalea), Spiraea media (Oriental spirea), Staphylea colchica (Colchis bladdernut), Staphylea trifolia (American bladdernut), Tulipa sp. (tulip), and Viburnum x burkwoodii (Burkwood Viburnum). Overwintering song sparrows (Melospiza melodia) have started laying their eggs in ground nests.

Pests/Problems: Winter moth (Operophtera brumata) is extremely active on susceptible plants throughout the landscape. Garlic mustard (Alliaria petiolata) is in full bloom. Dandelions (Taraxacum sp.) are in full bloom, easily seen throughout the greened up turf. Greater celandine (Chelidonium majus) is just beginning to come into bloom. Established Japanese knotweed (Fallopia japonica) is already four feet in size in some areas while in other areas it is just beginning to emerge. Weeds continuing to bloom include: Cardamine hirsuta (hairy bittercress), Draba verna (shadflower), Glechoma hederacea (ground ivy), Lamium amplexicaule (henbit), Lamium purpureum (red dead-nettle), and Stellaria media (common chickweed). Poison ivy (Toxicodendron radicans) is just beginning to leaf out. For allergy sufferers, the primary culprits currently distributing pollen are elms, junipers and maples. Ticks are highly active at this time.

Metro West (Acton)

General Conditions: Spring is exploding with the recent spell of summer like temperatures and April showers. Lawns continue to green up and the mowing crews are out in force. The total rainfall recorded for the month of April was 5.94", significantly more than the monthly average of 4.16". Woody plants seen in bloom this past week are Amelanchier spp. (Shadbush, Serviceberry), Cercis canadensis (Redbud), Chaenomeles speciosa (Common Flowering Quince), Cornus florida (Dogwood), Daphne x burkwoodii 'Carol Mackie' (Daphne), Forsythia spp. (Forsythia), Fothergilla gardenii (Dwarf Fothergilla), F. major (Large Fothergilla), Halesia tetraptera (Mountain Silverbell), Magnolia x loebneri 'Merrill', (Merrill Magnolia), M. x soulangeana (Saucer Magnolia), M. 'Butterflies' (Butterflies Magnolia), M. 'Yellow Lantern (Yellow Lantern Magnolia), Malus spp. (Apple, Crabapple), Pieris japonica (Japanese Pieris), Prunus serrulata 'Kwanzan' (Kwanzan Cherry), P. japonica (Flowering Almond), P. serotina (Black Cherry), Pyrus spp. (Pear), Rhododendron mucronulatum (Korean Rhododendron), R. 'P. J. M.', Rhododendron spp.,(early flowering azaleas), Spiraea thunbergii (Thunberg Spirea), Syringa vulgaris (Common Lilac), Vaccinium angustifolium (Lowbush Blueberry), V. corymbosum (Highbush Blueberry) Viburnum x burkwoodii (Burkwood Viburnum) and V. x burkwoodii 'Mohawk' (Mohawk Burkwood Viburnum). Contributing even more color and interest to the landscape are some flowering herbaceous plants and spring ephemerals including: Ajuga reptans (Bugleweed), Anemone nemorosa (Wood Anemone), Aquilegia canadensis (Columbine), Arisaema triphyllum (Jack-in-the-Pulpit), Aurinia saxatilis (Basket of Gold), Caltha palustris (Marsh Marigold), Claytonia virginica (Virginia Spring Beauty), Dicentra canadensis (Squirrel Corn), D. cucullaria (Dutchman's Breeches), D. eximia (Fringed Bleeding Heart), D. spectabilis (Old Fashioned Bleeding Heart), Epimedium x versicolor 'Niveum' (White Flowering Barrenwort), E. x versicolor 'Roseuem' (Pink Flowering Barrenwort), E. versicolor 'Sulphureum' (Yellow Flowering Barrenwort),, Helleborous x hybridus (Christmas Rose), Hyacinthus spp. (Hyacinth), Iberis sempervirens (Evergreen Candytuft), Linaria annua (Money Plant), Mertensia virginica (Virginia Bluebells), Muscari sp. (Grape Hyacinth), Myosotis sylvatica (Forget-me-not), Narcissus spp. (Daffodil), Omphalodes verna (Blue-eyed Mary), Pachysandra procumbens (Allegheny Spurge), P. terminalis (Japanese Pachysandra), Phlox subulata (Moss Phlox), Polygonatum commutatum (Great Solomon Seal), P. odoratum 'Variegatum' (Variegated Solomon’s Seal), Primula spp. (Primrose), Pulmonaria longifolia (Lungwort), Shortia uniflora (Nippon Bells), Stylophorum diphyllum (Wood Poppy), Tiarella cordifolia (Foam Flower), Trillium erectum (Red Flowering Trillium), T. grandiflorum (WhiteFlowering Trillium), T. sessile (Toadshade Trillum), Tulipa spp. (Tulip), Uvularia sessilifolia (Bellflower), Vinca minor (Periwinkle), Viola spp. (Violet) and Waldsteinia ternata (Barren Strawberry).

Pests/Problems: Snowball Aphid and the distorted leaves it causes are evident on Viburnums and caterpillars are actively feeding on the foliage of Acer (Maple), Malus (Crabapple), and Tilia (Linden). Ticks and black flies are feeding and active. Many weeds are in flower including one of the most invasive of all time, Alliaria petiolata (Garlic Mustard), which is just beginning to bloom and can easily be seen with because of its white flowers and it is growing everywhere including on roadsides and in woodlands, wetlands and gardens. Other weeds seen in bloom now are Glechoma hederacea (Ground Ivy), Lamium purpureum (Purple Dead Nettle) and Taraxacum officinale (Dandelion). Weeds emerging but not in bloom include: Arctium minus (Lesser Burdock), Impatiens capensis (Touch-me-not) and Polygonum cuspidatum (Japanese Knotweed). Be aware of Toxicodendron radicans (Poison Ivy). It is beginning to leaf out so it is fairly easy to detect its shiny red leaves of three.

Central Region (Boylston)

General Conditions: The weather remains variable - typical for spring. Warm sunny days contrast with cool, wet days but trees are gradually leafing out and many things are bursting into bloom. Hybrid tulips are at their peak in this region while Narcissus are finishing. Viburnum carlesii, V. carlcephalum, V. alnifolium are in full bloom as are Cercis canadensis, Prunus pensylvanica, Magnolia ‘Elizabeth’ and M. ‘Daybreak’, Iberis sempervirens, Spiraea thunbergii, Acer japonicum cultivars, Mertensia virginica, Aurinia saxatilis, Trillium erectum, Claytonia virginica, Helleborus x hybridus, Anemone blanda, Pulmonaria cevennensis, Muscari armeniacum, Adonis vernalis, Pulsatilla vulgaris, Phlox subulata, and Dicentra cucullaria. Among the plants beginning to bloom are Halesia sp., Fothergilla gardenii, Epimedium species and cultivars.

Pests/Problems: Glechoma hederacea, Taraxacum officinale, ticks, voles and chipmunks are eating tulip bulbs, Eastern Tent Caterpillar webs are expanding, black flies are ramping up.

Pioneer Valley Region (Amherst)

General Conditions: We continue to experience every type of spring weather in the Pioneer Valley. Over this past reporting period, it’s been sunny and warm, cloudy and mild, rainy and cool and very windy. High temperatures have ranged from the low 50s (5/1) to the middle 80s (4/28), while low temperatures oscillated between the mid-30s to mid-50s. Wind gusts up to 33 mph were recorded at Barnes Airport in Westfield on 5/2, scattering flowering parts and small stems across the landscape. Once again, multiple forms of precipitation were observed, from fog to light mist and even a fast-moving, strong thunderstorm during the late hours of Monday, 5/1. Tree canopies are gradually taking shape, slowed a bit by the recent cold front. Sugar maple, ash, linden, katsura and crabapple trees are approaching full leaf out while oaks and beech are beginning to flush new foliage. Several conifers are breaking bud at this time as well, with larch and yew the most advanced at this time. The long-term forecast calls for below-average temperatures but now that many trees have flushed, they’ll slowly expand despite the cooler temperatures. The crabapples on the UMass campus (>400 in total) look fantastic right now. Crabapples certainly have their detractors, as the fruit can be messy in the fall (and the resulting seedlings the following spring an annoyance to weed) and they require regular intervention to remove a proliferation of trunk and branch suckers. But their cold hardiness, tolerance of abuse and dependable annual to biennial spring flowering makes it easy to understand why they’re so abundant. Overall, the landscape is rich with color and lawn grasses are growing at a rapid rate with regular mowing cycles already in place.

Pests/Problems: White pine candles are elongating, but we are still multiple weeks away from new needle development. Needle blight pathogens causing problems for white pine will be sporulating soon, if they are not already, given the regular rainfall, mild temperatures and cloud cover. Douglas-fir buds are breaking at this time. If Rhabdocline and Swiss needle cast have been a problem in the past, preventative fungicide treatments will be necessary to control these fungal pathogens. For trees in full sun settings without surrounding weeds and plantings, treatment is probably not necessary. But for trees exposed to shade or planted too close together, the diseases are seemingly inevitable. Arborvitae needle blight, caused by Phyllosticta and Pestalotiopsis, have impacted many arborvitae trees in landscape over the past several years. Pruning dead shoots and needles is critical to reduce inoculum in the canopy. Preventative fungicide treatments may be necessary to protect new growth, which is currently developing at this time. Hemlock, balsam and white fir are just beginning to flush new growth at this time. If the elongate hemlock scale is present, prepare to apply an appropriate insecticide as new needles are elongating. Continue to scout for and treat for the spruce spider mite on spruce, fir, arborvitae and hemlock. A strong stream of water can dislodge spider mites from infested needles and shoots, reducing populations on smaller trees, especially on interior canopy branches. According to the UMass Cold Spring Orchard, we are currently in the peak period for apple scab infection. With the rain and mild temperatures, we can expect high levels of infection for certain apple and crabapple trees in the landscape. In addition, cedar-apple and cedar-quince rust spore masses are abundant on Juniperus. The rain, persistent cloud cover and winds have provided ideal conditions for spore production and dispersal. While juniper and redcedar are fairly resistant to both diseases, significant damage can ensue on rosaceous hosts with dense canopies, such as serviceberry (Amelanchier). Japanese knotweed is actively growing and all means should be utilized to rid the landscape of this aggressive, non-native plant. Don’t be fooled by recent articles touting the benefits of this plant for forage, wildlife habitat and late season pollen. Japanese knotweed can adversely affect riparian environments, reducing the diversity and abundance of native plants. In one study, green frog foraging success was significantly reduced by knotweed, likely due to decreased abundance of available prey. Poison ivy and Oriental bittersweet are actively growing, so take precautions for the former and actions against the latter. Bittersweet vines can girdle small trees and cause canopy dieback and decline by choking the canopy of larger trees. Deer ticks are active and abundant and will continue to be for the upcoming season. Utilize the UMass laboratory of medical zoology for testing of ticks found embedded for tick-borne pathogens.

Berkshire Region (Great Barrington)

General Conditions:The past week began with some very warm high temperature readings, 81° F on April 28th, but by the weekend (April 30th), a cold front moved through, bringing with it some strong but brief winds and rain. Heavy rains fell on the night of May 1, again with some strong winds which brought down some branches though no power outages occurred. The remainder of this week - and well into next - appears to be cooler than normal with a possibility of frost in some locales on a few mornings. For several weeks, there has been a roller coaster pattern to the weather, i.e., a few days of cloudy and often damp days, followed by a day or two of sunny and warm conditions, followed again by several days of cloudy and sometimes wet weather, followed by a day or two of sun. Currently, May is starting off as cool and damp. Warm weather and rain brought down the blossoms on early blooming cherries and star magnolias. Otherwise, the landscape is flush with flowering trees, shrubs, bulbs, herbaceous perennials, and wildflowers. May is the month when most ephemeral woodland wildflowers are in bloom. With recent rains, soil moisture levels are high and soils, especially in central and northern parts of the county are saturated.

Pests/Problems: The newest pest emergence of the past week was the viburnum leaf beetle. The larvae of were observed on expanding leaves of Viburnum lantana. Lily leaf beetle adults remain active though little damage has been seen as the beetles are preoccupied with mating. Carpenter bees, wasps, mosquitoes, ticks, sowbugs, and millipedes are plentiful. Sowbugs and pillbugs are beneficial decomposers by feeding on decaying organic matter in the garden. Despite a search of black cherry, crabapple, and apple trees at various sites, there are still no sightings or reports of eastern tent caterpillars (ETC). This is the second year in a row that there have been no ETC found during scouting, suggesting that the population has been at a low point on the sine curve of population growth. Some marginal necrosis and browning of foliage on broadleaf evergreens is evident but the extent of such damage is minimal. Overall, plant and pest development has been slow. Garlic mustard (Alliaria petiolata) is in flower. This is one of the most invasive herbaceous plants in this area and is a threat to native plants as it displaces them. It is imperative that the plants be mowed down before they set seed. Deer and rabbit browsing on tender shoots of woody and herbaceous plants remain at a high level.

Regional Scouting Credits

  • CAPE COD REGION - Russell Norton, Horticulture and Agriculture Educator with Cape Cod Cooperative Extension, reporting from Barnstable.
  • SOUTHEAST REGION - Deborah Swanson, UMass Extension Horticulturist for Plymouth County - Retired, reporting from Hanson.
  • NORTH SHORE REGION - Geoffrey Njue, Green Industry Specialist, UMass Extension, reporting from the Long Hill Reservation, Beverly.
  • EAST REGION - Kit Ganshaw & Sue Pfeiffer, Horticulturists, reporting from the Arnold Arboretum, Jamaica Plain.
  • METRO WEST REGION – Julie Coop, Forester, Massachusetts Department of Conservation & Recreation, reporting from Acton.
  • CENTRAL REGION  -  Joann Vieira, Superintendent of Horticulture, reporting from the Tower Hill Botanic Garden, Boylston.
  • PIONEER VALLEY REGION - Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, reporting from UMass Amherst.
  • BERKSHIRE REGION - Ron Kujawski, Horticultural Consultant, reporting from Great Barrington.

Woody Ornamentals

Diseases

Recent pests and pathogens of interest seen in the UMass Extension Plant Diagnostic Lab:

Needle blight of arborvitae (Thuja occidentalis) caused by Phyllosticta thujae. Trees are less than 10-years-old and have been present at the site for six to eight years. The setting is full sun with sandy soils and no supplemental irrigation. Last summer, scattered branch dieback developed throughout the canopy on several trees. One tree has died outright. A combination of drought and needle blight, with possibly some other interacting stresses, is likely contributing to decline and death.

Gray leaf blight caused by Pestalotiopsis and marginal blight caused by Phyllosticta on rosebay and catawba rhododendron (Rhododendron maximum and R. catawbiense). Multiple shrubs that are approximately five to seven-years-old, in a shaded setting with drip irrigation. Samples exhibited undersized 2016 foliage, brown to gray leaf margins and stem dieback. The shrubs were transplanted approximately three years ago and the symptoms developed prior to this spring. A combination of transplant shock, winter burn and secondary pathogen attack have weakened the plants and degraded their aesthetic value.

Severe infestation of the elongate hemlock scale (Fiorinia externa) and needle cast caused by Rhizosphaera on true fir (Abies). The trees are most likely balsam fir and were planted approximately 25 years ago as part of a Christmas tree farm that went fallow and is now a residential neighborhood. Around 15 trees are declining and exhibit (browning needles, canopy dieback and death). The undersides of the needles were severely infested; it is likely the trees have been harboring this pest for many years. Exponential population growth has appeared to reach its peak for these trees, which are rapidly transitioning from declining to dead.

Needle blight caused by Septorioides strobi of eastern white pine (Pinus strobus). Tree is roughly 75-years-old and in autumn of 2016, began to exhibit symptoms that are typical of the recent white pine decline (browning needle tips, progressively worsening throughout the canopy). The site is full sun and near a pond, therefore there should be ample soil moisture for this tree. Septorioides has not been officially classified as a pathogen of eastern white pine, but is widely abundant on browning needle tips on landscape trees.

Report by Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass Amherst.

Insects

Woody ornamental insect and non-insect arthropod pests to consider, a selected few:

New Pollinator Protection Resource Online: The Massachusetts Department of Agricultural Resources has developed a Massachusetts Pollinator Protection Plan. It is a set of voluntary guidelines that discuss best management practices for stakeholders seeking to promote the health of the European honeybee and other pollinators. This document includes information for beekeepers, pesticide applicators, land managers and farmers, nurseries and landscapers, and homeowners and gardeners. Please locate the MA Pollinator Protection Plan for more information here: http://www.mass.gov/eea/docs/agr/farmproducts/apiary/pollinator-plan.pdf.

  • Young, tiny gypsy moth caterpillars continue to hatch at a site in Belchertown, MA on 5/3/17 and are seen moving away from egg masses at this time. (Simisky, 2017) Gypsy moth caterpillars that hatched from egg masses last week have begun to balloon onto young oak leaves at a site in Belchertown, MA on 5/3/17. Hatch continues and dispersal has begun. (Simisky, 2017) Gypsy Moth: Lymantria dispar overwintered egg masses laid by female moths in 2016 continue to hatch and tiny, dark and hairy caterpillars may be seen resting on top of egg masses in cooler portions of the state – however, many areas may already be experiencing caterpillar dispersal (ballooning) at this time. Egg hatch has been noted and reported at locations including but certainly not limited to spotty areas of: Belchertown, Dennis, Hanson, Hingham, Petersham, Randolph, Sandwich, Sturbridge, and near the Wachusett Reservoir. Those reports came in between 4/26/17 and 4/30/17. Typically, gypsy moth egg hatch occurs the first week in May in Massachusetts, but with our current GDD accumulations hatch began early this year and is well under way. In some areas, hatch may be finished and the tiny caterpillars will disperse. (Dispersing caterpillars were observed in Hanson, MA on 4/29/17, crawling away from their egg masses and suspected ballooning was reported in that location on 5/2/17. Dispersed caterpillars were observed on newly opened oak leaves on 5/3/17 at a site in Belchertown, MA; however, some egg masses continue to hatch at that site and caterpillars were still seen resting on top of them. Egg masses that began hatching at that location last week are devoid of caterpillars, again indicating ballooning has begun at that site.) For more information about gypsy moth egg hatch, please visit: https://ag.umass.edu/landscape/news/gypsy-moth-egg-hatch-has-begun-in-massachusetts.

To treat individual, landscape ornamental and shade trees using the active ingredient Btk (Bacillus thuringiensis Kurstaki) for gypsy moth, be sure that the newly hatched caterpillars have settled to feed on fully expanded foliage and are roughly between ¼ - ¾ inch in length. Larger caterpillars are less susceptible to Btk. These applications should be made when very young caterpillars are actively feeding on host plant leaves, as it must be ingested to be effective.

Gypsy moth host plants include but are not limited to oak (favored), maple, birch, poplar, and many others. Caterpillars will feed on conifers (such as eastern white pine, hemlock, and spruce) when favored resources have been exhausted. (Note: winter moth and gypsy moth share some common host plants. Therefore, where populations of these two insects overlap in Massachusetts, the same tree may be defoliated by winter moth and then again by gypsy moth following in the same season.) Caterpillar dispersal occurs by crawling to the canopy of their host plant, where they can scatter using a technique known as “ballooning”. Ballooning occurs when very young caterpillars spin a silken thread and catch the wind to blow onto a new host plant once the thread breaks. This method of dispersal can lead to host plants becoming defoliated that previously did not have egg masses directly on them, however egg masses may be present on nearby oaks, for example, and provide a local population of caterpillars.

Patchy areas across mostly central and eastern Massachusetts experienced elevated populations of gypsy moth and significant amounts of defoliation in 2016 (see the Insects section of the archived 2016 Landscape Messages between April 29 and July 29). The Massachusetts Department of Conservation and Recreation aerially mapped approximately 350,000 acres of defoliation across Massachusetts last year, attributed to gypsy moth. State officials warn the public about another year of defoliation from gypsy moth as predicted for 2017: http://www.mass.gov/eea/agencies/dcr/pr-2017/another-year-of-defoliation-from-gypsy-moth-in-2017.html. That web page also links to a map of the 2016 defoliation from gypsy moth, which may provide a reference regarding areas that may be impacted by this insect again in 2017.

We can hope for elevated rainfall in the months of May and June, which helps facilitate the successful infection of younger gypsy moth caterpillars with the insect-killing fungus Entomophaga maimaiga. This fungus overwinters in the soil litter in tough, protected asexual resting spores, which can survive in this state for years. Having lacked much precipitation most recently during the springs of 2015 and 2016, it is thought that our current expanding populations of gypsy moth are at least in part a result of a lack of infection in the caterpillar population by this fungus. Hopefully Massachusetts will see more normal rainfall amounts this season. Only time will tell. So far, according to reports from the Northeast Regional Climate Center, last month (April) showed most (not all) of Massachusetts at or above normal precipitation amounts for that month. As a region, they report from the U.S. Drought Monitor that the Northeast became free of severe drought for the first time since late June 2016 (reported on 4/27/17). Although the rain might impede our outdoor recreational plans in some ways, let us hope this trend continues! See: http://www.nrcc.cornell.edu/regional/drought/drought.html.

We can also hope areas in Massachusetts that did not experience much gypsy moth defoliation last year (areas such as most of Berkshire County) will be mostly spared in 2017 in comparison to those areas who suffered last year in southern central and eastern Massachusetts. For more information about gypsy moth, please visit: http://ag.umass.edu/landscape/fact-sheets/gypsy-moth and return to the Landscape Message for timely updates about this pest and others throughout the season. An excellent article written by Dr. Joseph Elkinton and Jeff Boettner of the University of Massachusetts about the 2016 outbreak and the history of this insect in Massachusetts may be found here: http://www.mass.gov/eea/agencies/dfg/dfw/publications/gypsy-moth-outbreak-of-2016.html.

Tiny caterpillars are now feeding within the newly expanding and developing foliage of their host plants and in some cases may be loosely webbing together foliage as they feed. Winter moth caterpillars have been reported on (but not limited to) apple, crabapples, Japanese maple, Norway maple, red maple, and roses by scouts this season. As of 5/1/17, 1st, 2nd, and 3rd instar winter moth caterpillars had all been observed in Hanson, MA. At that location, most caterpillars are currently noted to be in the 2nd and 3rd instar stage. Reports continue to indicate that in certain areas this year, winter moth caterpillar numbers are reduced. Please see the Regional Reports above for local information regarding this insect.

For individuals managing winter moth in ornamental plants, depending on the active ingredient being used, waiting until host plant leaves open completely may be important for management, particularly if Bacillus thuringiensis Kurstaki (Btk) is the active ingredient of choice. Btk must be ingested by actively feeding, young caterpillars to be effective. Applying Btk to partially open buds for winter moth management will not have the desired effect. Spinosad is also effective through ingestion and contact on winter moth (including older caterpillars) once ornamental plant leaves have fully expanded, however it should not be applied to plants in flower as it is toxic to pollinators until it has dried (which can take 1-3 hours depending upon local environmental conditions).

Winter moth is a non-native insect that was identified in Massachusetts for the first time in 2003 following persistent reports of defoliation in eastern areas of the state such as Cape Anne and on the North Shore near Cohasset, Hingham, and Rockland on the South Shore in the late 1990’s. For more detailed information about the history of this insect pest in North America and Massachusetts, please visit the newly updated (March, 2017) fact sheet: Winter Moth in Massachusetts: History and Biological Control ( https://ag.umass.edu/landscape/fact-sheets/winter-moth-in-massachusetts-history-biological-control ).

This fact sheet also includes updates regarding the progress of the work of Dr. Joseph Elkinton’s laboratory group at the University of Massachusetts and their efforts towards the biological control of winter moth using Cyzenis albicans, a tachinid fly. The fly parasitizes the caterpillars of winter moth specifically. In other areas, such as Nova Scotia where winter moth was also problematic, this fly used for biological control has been successful in reducing winter moth to a non-pest. C. albicans has been released across 41 sites in Massachusetts and has been established in at least 17 of those sites as evidenced through the recovery of flies in winter moth in subsequent years. In one site in Wellesley, these flies have been observed to be spreading from the initial release location and their populations have increased alongside an observed decrease in the winter moth population there. For more information, please visit the above mentioned fact sheet.

  • Black Vine Weevil: Otiorhynchus sulcatus damage is apparent on rhododendron and taxus, but can also be seen on azalea, mountain laurel, and Euonymus. Adult weevils feed along the leaf/needle margins and create rounded notches. Inspect foliage of these plants for notching from last season’s feeding. Larvae, which dwell in the soil, are conducting their heaviest feeding on plant roots at this time. Pupation will occur by the end of this month. Adults will emerge in June and create new damage to leaves for this season. All individuals are females and reproduce asexually. This insect has developed resistance to many chemical insecticides. Entomopathogenic nematodes such as Steinernema carpocapsae, S. feltiae, and Heterorhabditis bacterio-phora work well against this insect, particularly on containerized plants. Results in the landscape vary. Wetting the soil thoroughly prior to application and keeping it wet for at least 5 days following application can help increase the efficacy of the nematodes. Burlap laid around the base of plants during the time adults are active, by the end of May through August, can be inspected weekly for adult weevils which can be killed before egg laying.
  • Boxwood Psyllid: Psylla buxi is feeding on newly emerged boxwood foliage with its piercing-sucking mouthparts. This feeding may not cause yellowing or loss of foliage, but will lead to the cupping of new leaves which can be an aesthetic issue for some. If population numbers are low, management of this pest may not be necessary. Nymphs of this insect may be managed between 290-440 GDD’s.
  • Eastern tent caterpillars (ETC) continue to grow and feed and their tents become increasingly apparent. The ETC egg mass with tapered, round-ish edges can be seen in the background. Observed in Belchertown, MA on 5/3/17. (Simisky, 2017) Eastern Tent Caterpillar: Malacosoma americanum young, but growing, caterpillars are expanding their tents as they feed on tender, new plant foliageand are quite visible at this time. Scout for, remove, and destroy any small eastern tent caterpillar tents in the crotches of branches on susceptible hosts such as cherry and crabapple. If the tents and the growing caterpillars within are found early enough, this is a great way of removing these insects without the use of chemicals. Other host plants impacted by this native insect can include apple, ash, birch, willow, maple, oak, poplar, and witch-hazel.
  • Elongate Hemlock Scale: Fiorinia externa is found on eastern, Carolina, and Japanese hemlock, as well as yew, spruce, and fir. Crawlers will be present this month and throughout the growing season and the overlap of many developmental stages at any given time can be observed.
  • European Pine Sawfly: Neodiprion sertifer caterpillars or sawflies are active. Reports of this insect on Mugo pine were made on 4/27/17 in Framingham. At that time, the tiny, newly hatched sawflies were still located on the very needles from which they emerged. For other locations, see the Regional Reports above. The primary host in MA is Mugo pine but it can be found on Scots, red, jack, and Japanese red pine, but is also found on white, Austrian, ponderosa, shortleaf, and pitch pine when near the aforementioned species. This dark colored caterpillar feeds in tight groups and small numbers can be pruned away and destroyed. Larger numbers can be treated with an insecticidal soap spray when the caterpillars are still small. Spinosad products can be used whenever the caterpillars are actively feeding, usually by mid-May and when caterpillars are still small. Bacillus thuringiensis Kurstaki is not effective against sawflies.
  • Lily Leaf Beetle: Lilioceris lilii should be monitored for at this time. Scouts report in Berkshire County that the adults are mostly preoccupied with mating at this time. Similar reports come out of Hanson, MA at this time. Management can be achieved by hand-picking and removing adults and larvae. Some chemical management options are available for this insect, but if caught early mechanical management may be effective.

The University of Rhode Island Biological Control Lab is researching ways to find a natural method to combat these beetles. Small parasitic insects have been established in lily plots in Cumberland, RI and Wellesley, MA in hopes that these insects will disperse naturally to reduce the effects of the lily leaf beetle. If you have larvae in your yard (or a customer’s yard), please send to URI, following the instructions on the URI Biocontrol Lab website: http://web.uri.edu/biocontrol/home/lily-leaf-beetle-larval-collections-2016-mailing-instructions/

  • Snowball Aphid: Neoceruraphis viburnicola has been observed on certain species of viburnum. This insect is particularly noticeable on V. opulus, V. prunifolium, and V. acerifolia. Stem mothers, appearing blueish-white, can be found in curled up and distorted foliage. See Regional Reports. This pest is mostly aesthetically damaging; however, if chemical management options are deemed necessary, foliar applications of products containing active ingredients such as permethrin can be made at this time.
  • Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. See the Regional Reports regarding areas where this insect has been noted to be active thus far this season. This beetle feeds exclusively on many different species of viburnum including but not limited to susceptible plants such as V. dentatum, V. nudum, V. opulus, V. propinquum, and V. rafinesquianum. Larvae may be treated with a product containing spinosad. Some viburnum have been observed to have varying levels of resistance to this insect, including but not limited to V. bodnantense, V. carlesii, V. davidii, V. plicatum, V. rhytidophyllum, V. setigerum, and V. sieboldii. More information about viburnum leaf beetle may be found at http://www.hort.cornell.edu/vlb/.
  • Chilli Thrips: *A non-native insect has been confirmed in Massachusetts for the first time.* The non-native, exotic chilli thrips (Scirtothrips dorsalis) has been recently confirmed from two samples of damaged Hydrangea spp. foliage from two residential landscapes located in Barnstable County, MA submitted to the UMass Plant Diagnostics Laboratory. At this time, this pest has not been confirmed in nurseries or greenhouses in Massachusetts or on any other host plants. Due to the limited number of samples, the significance of chilli thrips in Massachusetts is not yet known. This species of thrips is a significant global pest of economically important ornamental, vegetable, and fruit crops in southern and eastern Asia, Oceania, and parts of Africa. It was first determined to be established in the United States in 2005 in Florida, although previous interceptions of this pest were detected. It is reportedly a pest of over 100 host plants belonging to over 40 plant families, including, but not limited to, pepper, strawberry, blueberry, cotton, rose, peanut, Japanese privet, Rhododendron spp., Viburnum spp., eggplant, grapes, melon, tobacco, and tomato. For more information, please visit this Chilli Thrips Fact Sheet (https://ag.umass.edu/landscape/fact-sheets/chilli-thrips) available on the UMass Extension Landscape, Nursery, and Urban Forestry Program web page.
  • Asian Longhorned Beetle, Anoplophora glabripennis, ALB: Look for signs of an ALB infestation which include perfectly round exit holes (about the size of a dime), shallow oval or round scars in the bark where a female has chewed an egg site, or sawdust-like frass (excrement) on the ground nearby host trees or caught in between branches. Be advised that other, native insects may create perfectly round exit holes or sawdust-like frass, which can be confused with signs of ALB activity.

The regulated area for Asian longhorned beetle is 110 miles2 encompassing Worcester, Shrewsbury, Boylston, West Boylston, and parts of Holden and Auburn. If you believe you have seen damage caused by this insect, such as exit holes or egg sites, on susceptible host trees like maple, please call the Asian Longhorned Beetle Eradication Program office in Worcester, MA at 508-852-8090 or toll free at 1-866-702-9938. Adult insects of this species will not be present at this time of year.

To report an Asian longhorned beetle find online or compare it to common insect look-alikes, visit: http://massnrc.org/pests/albreport.aspx or https://www.aphis.usda.gov/pests-diseases/alb/report.

  • Emerald Ash Borer (EAB): Agrilus planipennis readily attacks ash (Fraxinus spp.) including white, green, and black ash and has also been found developing in white fringe tree (Chionanthus virginicus). Adult insects of this species will not be present at this time of year. Signs of an EAB infested tree may include (at this time) D-shaped exit holes in the bark (from adult emergence in previous years), “blonding” or lighter coloration of the ash bark from woodpecker feeding (chipping away of the bark as they search for larvae beneath), and serpentine galleries visible through splits in the bark, from larval feeding beneath. Positive identification of an EAB-infested tree may not be possible with these signs individually on their own.

For a map of the known locations of emerald ash borer in the state, as well as further information about this insect, please visit: https://ag.umass.edu/fact-sheets/emerald-ash-borer. If you believe you have located EAB-infested ash trees, particularly in an area of Massachusetts not identified on the map provided, please follow the instructions below.

Concerned that you may have found an invasive insect or suspicious damage caused by one? Need to report a pest sighting? If so, please visit the Massachusetts Introduced Pests Outreach Project: http://massnrc.org/pests/pestreports.htm.

A note about Tick Awareness: deer ticks (Ixodes scapularis), the American dog tick (Dermacentor variabilis), and the lone star tick (Amblyomma americanum) are all found throughout Massachusetts. Each can carry their own complement of diseases. Anyone working in tick habitats (wood-line areas, forested areas, and landscaped areas with ground cover) should check themselves regularly for ticks while practicing preventative measures. Have a tick and need it tested? Visit the web page of the UMass Laboratory of Medical Zoology (www.tickdiseases.org) and click on the red Test a Tick button for more information.

Report by Tawny Simisky, Extension Entomologist, UMass Extension Landscape, Nursery, & Urban Forestry Program

Management Practices

Halesia carolina, Carolina Silverbell Halesia carolina, Carolina Silverbell Halesia carolina, Carolina Silverbell Halesia carolina, Carolina Silverbell Plant of the week: Halesia carolina, Carolina Silverbell

Halesia carolina is a small to medium sized spring flowering tree growing 30-40’ tall and 25-35’ wide. Plants are broad and rounded with irregular branching that often begins low on the trunk. Carolina Silverbell gets its common name from the pendulous, white, bell-shaped flowers in clusters of up to 5. Flowers occur in early May and are best appreciated when they can be viewed closely. Leaves are ovate, 2-5” long and 1-2.5” wide with a slightly serrated margin. Fall color is yellow-green and develops early. The fruit is four-winged and oblong changing from green to tan and persisting into winter. Bark is smooth, gray with creamy-white striping with bark on twigs exfoliating in fine silvery shreds. Halesia carolina can be a nice specimen or is good for a shrub border or woodland garden. Plants are best grown in a well-drained soil in full sun to part shade. Cultivars offer pink flowers, variegated foliage, or smaller forms.

Report by Mandy Bayer, Extension Assistant Professor of Sustainable Landscape Horticulture, UMass Stockbridge School of Agriculture


Additional Resources

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For commercial growers of greenhouse crops and flowers - Check out the New England Greenhouse Update website

For professional turf managers - Check out Turf Management Updates

For home gardeners and garden retailers - Check out home lawn and garden resources. UMass Extension also has a Twitter feed that provides timely, daily gardening tips, sunrise and sunset times to home gardeners, see https://twitter.com/UMassGardenClip

Diagnostic Services

A UMass Laboratory Diagnoses Landscape and Turf Problems - The UMass Extension Plant Diagnostic Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other green industry professionals. It provides woody plant and turf disease analysis, woody plant and turf insect identification, turfgrass identification, weed identification, and offers a report of pest management strategies that are research based, economically sound and environmentally appropriate for the situation. Accurate diagnosis for a turf or landscape problem can often eliminate or reduce the need for pesticide use. For sampling procedures, detailed submission instructions and a list of fees, see Plant Diagnostics Laboratory

Soil and Plant Nutrient Testing - The University of Massachusetts Soil and Plant Nutrient Testing Laboratory is located on the campus of The University of Massachusetts at Amherst. Testing services are available to all. The function of the Soil and Plant Nutrient Testing Laboratory is to provide test results and recommendations that lead to the wise and economical use of soils and soil amendments. For complete information, visit the UMass Soil and Plant Nutrient Testing Laboratory web site. Alternatively, call the lab at (413) 545-2311.

Ticks are active at this time! Remember to take appropriate precautions when working and playing outdoors, and conduct daily tick checks. UMass tests ticks for the presence of Lyme disease and other disease pathogens. Learn more