UMass Extension's Landscape Message is an educational newsletter intended to inform and guide Green Industry professionals in the management of our collective landscape. Scouts compile and record environmental and phenological data for locations throughout Massachusetts to aid in the monitoring of plant and pest development, the planning of management strategies, and the creation of site-specific records for future reference. Detailed reports from Extension specialists on growing conditions, pest activity, and cultural practices for the management of woody ornamentals, trees, and turf are regular features. UMass Extension has updated the following issue 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 22. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.
Scouting Information by Region
Regional Notes
Cape Cod Region (Barnstable)
General Conditions: It was a lovely week on Cape Cod. While not as warm as off Cape, most daytime temperatures were in the upper 70s F, flirting with 80º F on 5/11, and nighttime lows were in the upper 50s F. It was a bit foggy over the weekend but the sun came out every afternoon. It has now returned to more seasonable temperatures, with high back to the 60s F and nights getting into the upper 40s F. Plant development really jumped during this reporting period, with deciduous trees seemly leafing out overnight. Pollen counts are quite high. Many deciduous shrubs are in bloom, including Fothergilla, ‘Ogon’ spirea, and Mayflower viburnum. Creeping phlox and Pulmonaria are blooming in the perennial garden. ‘Kwanzan’ cherries are just coming into bloom. Pests/Problems: Winter moth caterpillars are in the free feeding stage and early damage can be seen on young leaves. Gypsy moth caterpillars, although not common any more, are also hatching. This appears to be a big year for eastern tent caterpillar, especially on the Upper Cape. Some wild cherry trees have multiple webs, and affected crabapples have also been observed. The webs are enlarging so try to remove them before they get much larger on crabapple. Lily leaf beetle adults are actively feeding and laying eggs. Crush clusters of the small, reddish colored eggs that are on the foliage. Carpenter bees, bumble bees, and honey bees are active. Mosquitoes are biting. Adult deer ticks are active; nymphs will be active soon. The Lone Star tick, a relatively new tick for the Cape, is reported to be established on Sandy Neck. Be on the lookout for this aggressive tick. It has a small white dot on the center of its back and its bites are said to hurt. Be sure to wear repellents and perform thorough tick checks at the end of the day. Soils are getting quite dry as the Cape has not received any soaking rain in several weeks. Be sure to water newly planted materials well. Mulch volcanoes are beginning to appear at the base of trees. This is not a recommended practice. Mulch should be spread out over roots and kept a few inches away from trunks of trees.
Southeast Region (Hanson)
General Conditions: Wow! Where did spring go? Warm weather this past week, with temperatures in the 70s and 80s, pushed plant development and now we are a week ahead with some plants. There is a considerable amount of overlap of plants in bloom, making for very colorful landscapes! Aesculus hippocastanum (Common Horsechestnut), Halesia sp. (Silverbell), Magnolia macrophylla and late blooming magnolia hybrids, Cercis canadensis, Cornus florida, crabapples, Exochorda racemosa (Pearlbush), Pieris japonica, Pieris floribunda (Mountain Pieris), Pieris 'Brouwer's Beauty', Viburnum 'Eskimo', Viburnum carlesii (Mayflower Viburnum), Viburnum ‘Mohawk’, Wisteria floribunda (Japanese Wisteria), Calycanthus floridus (Carolina allspice), Ilex x meserveae (Meserve hybrid Hollies), Rhododendron schlippenbachii (Royal azalea), Rhododendron carolinianum, Fothergilla sp., Spiraea prunifolia (Bridalwreath Spirea), Syringa sp., Loniceratatarica, Kerria, Daphne x burkwoodii 'Carol Mackie', Daphne tangutica, Weigela florida 'Versicolor', Iberis sempervirens, Pulmonaria, Trillium, Convallaria majalis (Lily-of-the-valley), Helleborus foetidus, Euphorbia polychroma, Lamium sp., Primula sp., Iberis sp., Brunnera macrophylla, Ajuga, Saruma henryi, Phlox subulata, Phlox divaricata, Myosotis sylvatica (Forget-me-not), Lunaria annua (honesty or money plant), Dicentra spectabilis (Bleeding heart), Dicentra eximia (fringed Bleeding heart), Corydalis scouleri, Tiarella cordifolia (Foam Flower), Mertensia virginica (Virginia bluebells), Violets, Vinca minor, Galium odoratum (Sweet Woodruff), Hyacinthoides hispanica, dwarf bearded Iris, Arisaema (Jack-in-the-pulpit), Polygonatum sp. (Solomon's Seal), tulips, and Epimedium sp., are in full bloom. Aristolochia macrophylla (formerly, durior) or Dutchman's pipe is in bloom. This is an old-fashioned native vine that was often used as a privacy screen on front porches. This vine is a source of food for the pipevine swallowtail. Lawns are lush and green. Hanson received 0.15 inches of rain and soils are very dry. The warm weather, combined with no rain, is stressing plants and many are wilting. Remind clients to water and to especially water newly planted trees and shrubs and those planted within the past 2-3 years that may not yet be established. Pollen, especially oak pollen, is everywhere and the weather forecasters are referring to it as a “Pollen Tsunami”. Pests/Problems:The warm weather also pushed insect development and most winter moth caterpillars are now in late 3rd instar and soon-to-be 4th. Damage by winter moth caterpillars is starting to show up. Continue to monitor susceptible trees and shrubs and manage, if needed. Winter moth caterpillars will continue to feed for the next 1-2 weeks, and can do considerable damage in that time before they pupate. This past week, the caterpillars have been ballooning and filling the air with “silk” and 3rd instar caterpillars. They are looking for food sources and will feed on understory plants like roses, Japanese maples, etc. Monitor for gypsy moth caterpillars which are active. Right now, the caterpillars are small and black with tiny hairs on their bodies which can cause allergic reactions (rash) in some people. Dr. Joe Elkinton’s staff reports seeing, high numbers of gypsy moth, in pockets of Freetown State Forest, Assonet, MA and Wompatuck State Park in Hingham, MA. Azalea leaf sawfly is active on deciduous azaleas, especially ‘Exbury’. This caterpillar-like larva is bright green and feeds on the leaf margin, making it difficult to see. It will devour the leaf down to the midvein, if left untreated. Bacillus thuringiensis (Bt) does not work on sawflies. Lily leaf beetle adults are active, mating and laying eggs on true lilies. There appears to be higher numbers of eastern tent caterpillars in the area this year. The silken “tents” are readily visible on Malus and Prunus species and are easily seen driving around Plymouth County. Hemlock woolly adelgid, spruce spider mite, aphids, woolly beech aphid, ants, wasps, hornets, mosquitoes, honeybees, mason bees, carpenter bees, bumblebees, mosquitoes, deer and dog ticks continue to be active. Reports continue to come in of the high number of deer ticks this year. The deer tick nymph stage is often thought to be very responsible for transmitting Lyme disease. In this stage the ticks are very tiny and are active for several months. To avoid being bitten and possibly contracting Lyme or one of the other tick-borne diseases, consider using a repellent, conduct tick checks frequently, shower or bathe after yard work and place clothes in the dryer to desiccate and kill any ticks. Azalea leaf gall (Exobasidium vaccinii), a fungal disease, has just started to appear on deciduous azaleas. Look for small, green galls and hand pick and remove and destroy before they become larger and turn white. Now as they come into bloom, is a good time to shear, cut back or remove Massachusetts invasive plants, barberry, autumn olive and burning bush. These actions will reduce seed production and help reduce the population of more of these invasive plants. Veronica, garlic mustard, ground ivy, and dandelions are in full bloom. American hollies have started to shed their older, yellow leaves which drop at this time of year. Turkeys have reappeared and the Tom’s are looking for mates... Oh joy.
North Shore Region (Beverly)
General Conditions: This reporting period felt more like a week in summer though it is early May. Temperatures were in the high 70s rising up to the 80s and high 80s on some of of the days. However unlike in summer the relative humidity was low except on the last day of the reporting period when the humidity went up significantly. It was also a very dry week with only 0.01 inches of rain received on the last day of the reporting period. We gained 79 growing degree days during this reporting period. There were many plants in full bloom or beginning to bloom. Woody plants seen full bloom include: Flowering dogwood (Cornus florida), Eastern Redbud (Cercis canadensis), White Eastern Redbud (Cercis canadensis), Elizabeth Cucumber tree (Magnolia acuminata), Oriental Cherry (Prunus serrulata var. spontanea), Amur Chokecherry (Prunus maackii), Tea crabapple (Malus hupehensis), Apples/crabapple (Malus spp.), Weeping Higan Cherry (Prunus subhirtella var. pendula), Cunningham’s white rhododendron (Rhododendron catawbiense), Burkwood viburnum (Viburnum burkwoodii), Large fothergilla (Fothergilla major), Royal azalea (Rhododendron schlippenbachii), Hardy orange tree (Poncirus trifoliata), Pinkshell Azalea (Rhododendron vaseyi), Fothergilla (Fothergilla gardenia), Common Elderberry (Sambucus nigra). Woody plants beginning to bloom include: Chinese Redbud (Cercis chinensis), Zumi crabapple (Malus x zumi var. calocarpa), Olga mezitt Rhododendron (Rhododendron 'Olga Mezitt'), Lilac (Syringa vulgaris), Blueberry (Vaccinium spp.). Herbaceous plants in bloom include: Honesty plant (Lunaria annua), Yellow archangel (Lamiastrum galeobdolon), Blue eyed Mary (Omphalodes verna), Vinca vine (Vinca major), Forget-me-not (Myosotis palustris), Barrenwort (Epimedium rubrum) and Trilliums (Trillium spp.) Pests/Problems: Many spring weeds are in bloom. Those seen in bloom include: Dandelion (Taraxacum officinale), Speedwell (Veronica serpyllifolia), Garlic mustard (Alliaria petiolata) and Lesser celandine (Ranunculus ficaria). Ticks are very active and mosquitoes are also active. Make sure you remove any standing water to prevent mosquito breeding areas.
East Region (Boston)
General Conditions: The landscape has experienced drastic changes over the past seven days; we gained 114 GDDs, doubling our current total. It certainly felt like summer had arrived; the average high for the week was 82º F, ranging from 73º F to a hot 90º F on Mother’s Day/Lilac Sunday! May began with two days of below average temperatures, but since then, temperatures have skyrocketed with every day well above average; we received 26.0 GDDs on May 10th. We received minimal precipitation. The increase in temperatures has shortened the bloom time of early magnolias (Magnolia sp.) and cherry (Prunus sp.); maples (Acer sp.), horse chestnuts (Aesculus sp.) and lindens (Tilia sp.) have fully leafed out. The landscape has become extremely colorful with many plants in bloom: Cydonia oblonga (common quince), Exochorda giraldii (redbud pearlbush), Fothergilla major (large fothergilla), Halesia monticola (mountain silverbell), H. tetraptera (Carolina silverbell), Lonicera sp. (honeysuckle), Rhododendron minus (Piedmont rhododendron), Rh. schlippenbachii (royal azalea), Rh. vaseyi (pinkshell azalea), Rhodotypos scandens (jetbead), Sorbus sp. (mountain ash), Staphylea trifolia (American bladdernut) and early Viburnum sp. (viburnum). Pests/Problems: We received only 0.03 inches of precipitation over the past seven days and a total of 0.2 inches over the past three weeks. Well maintained turf has gone from first cut to showing signs of stress. Weeds continue to thrive; winter annuals continue to flower and set seed, summer annuals are germinating. Alliaria petiolata (garlic mustard) has germinated while one-year old plants are in full bloom. Perennial weeds Cynanchum louiseae (black swallow-wort), Fallopia japonica (Japanese knotweed), and Urtica dioica (stinging nettle) have grown significantly. Winter moth continues to feed on susceptible hosts, azalea sawfly is active in its earliest stages, and spider mite is active on hemlock. Cooley spruce gall adelgids are visible on spruce; hydrangea leaftier is visible on hydrangea, forming their protective homes within the plant leaves. Pollen levels are high with oak, birch, maple, poplar, alder and ash flowering simultaneously with grasses; the lack of rain has not helped to reduce pollen in the air.
Metro West (Acton)
General Conditions: What happened to spring? Based on this past week’s weather, the heat and lack of precipitation, it would appear that we skipped right over it and jumped from winter right into summer! Temperatures were recorded in the 80s on five of the seven days in this reporting period with the highest temp of 88º recorded on the 10th. The area received a mere 0.02" bringing this month’s total precipitation to 0.03” and we gained 105.5 GDD during this recording period. Woody plants seen in bloom this past week are Aesculus hippocastanum (Horsechestnut), Amelanchier spp. (Shadbush, Serviceberry), Aronia arbutifolia (Black Chokecherry), 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), Leucothoe axillaris (Coast Leucothoe), Magnolia x soulangeana (Saucer Magnolia), M. 'Butterflies' (Magnolia Butterflies), M. 'Yellow Lantern (Yellow Lantern Magnolia), Malus spp. (Apple, Crabapple), Potentilla tridentata (Cinquefoil), Prunus serrulata 'Kwanzan' (Kwanzan Cherry), P. japonica (Flowering Almond), P. serotina (Black Cherry), Pyrus spp. (Pear), Rhododendron spp., Spiraea thunbergii (Thunberg Spirea), Syringa vulgaris (Common Lilac), Syringa spp. (Lilac), Vaccinium angustifolium (Lowbush Blueberry), V. corymbosum (Highbush Blueberry), Viburnum x burkwoodii (Burkwood Viburnum) and V. x burkwoodii 'Mohawk' (Mohawk Burkwood Viburnum). Woody vines in bloom are: Aristolochia labiata (Dutchman's pipe) and Wisteria floribunda (Japanese Wisteria). Contributing even more color and interest to the landscape are some flowering herbaceous plants and spring ephemerals including: Actaea pachypoda (White Baneberry), Ajuga reptans (Bugleweed), Anemone nemorosa (Wood Anemone), Aquilegia canadensis (Columbine), Arisaema triphyllum (Jack-in-the-Pulpit), Asarum europaeum (European Ginger), A. canadense (Canadian Wild Ginger), Aurinia saxatilis (Basket of Gold), Caltha palustris (Marsh Marigold), Claytonia virginica (Virginia Spring Beauty), Convallaria majalis (Lily of the Valley), Dicentra eximia (Fringed Bleeding Heart), D. spectabilis (Old Fashioned Bleeding Heart), Dodecatheon meadia (Shooting Star), Epimedium x versicolor 'Niveum' (White Flowering Barrenwort), E. x versicolor 'Roseuem' (Pink Flowering Barrenwort), E. versicolor 'Sulphureum' (Yellow Flowering Barrenwort), Helleborous niger (Christmas Rose), Hyacinthus spp. (Hyacinth), Iberis sempervirens (Evergreen Candytuft), Iris germanica (Bearded Iris), Linaria annua (Money Plant), Mertensia virginica (Virginia Bluebells), Muscari sp. (Grape Hyacinth), Myosotis sylvatica (Forget-me-not), Narcissus spp. (Daffodil), Nepeta spp. (Ornamental Catmint), Omphalodes cappadocica (Navelwort), Phlox divaricata (Canadian Phlox), P. x subulata (Moss Phlox), Polygonatum commutatum (Great Solomon Seal), P. odoratum 'Variegatum' (Variegated Solomon Seal), Primula spp. (Primrose), Stylophorum diphyllum (Wood Poppy), Tiarella cordifolia (Foam Flower), Trillium erectum (Red Flowering Trillium), T. grandiflorum (White Trillium), T. sessile (Toadshade Trillum), Tulipa spp. (Tulip), Uvularia sessilifolia (Bellflower), Vinca minor (Periwinkle), Viola spp. (Violet), Waldsteinia ternata (Barren Strawberry) and Zizia aptera (Heart-Leaved Alexander). Pests/Problems: Snowball Aphid and the distorted leaves it causes are evident on Viburnums, caterpillars are actively feeding on the foliage of Malus (Crabapple) and are easier to detect this week as are Imported Willow Leaf Beetles chewing on willow foliage. Ticks, mosquitoes and black flies are feeding and active. Many weeds are in flower including one of the nastiest invasives of all time, Alliaria petiolata (Garlic Mustard), which is easily seen with its white flowers growing 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). 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: Summery temperatures (in the 70s to upper 80s) and dry conditions made this past week feel more like early July than mid-May. The plants seem to agree, moving rapidly from an early spring stage to blooming and leafing out almost overnight. In bloom now in our region are the fragrant Viburnums (C carlesii, V. carlcephalum, V. Burkwoodii), Cercis canadensis, Magnolia ‘Coral Lake’ and ‘Daybreak’, Rhododendron ‘Olga Mezitt’, Pieris floribunda, P. ‘Brouwer’s Beauty’, Apples and Crabapples (Malus sp.), Prunus maackii, Jetbead (Rhodotypos scandens), Fotherilla gardenii and F. major, Halesia sp., Acer japonicum ‘Aconitifolium’, and Syringa laciniata. Enkianthus campanulatus, Rhododendron ‘Scintillation’, Aronia sp. and Red Horsechestnut (Aesculus carnea ‘Briotii’) are beginning to bloom. Among the herbaceous plants in bloom aer Mertensia virginica, Primula seiboldii, Epimedium cvs., Tulips, Dicentra spectabilis, Muscari armeniacus, Phlox stolonifera, P. subulata, Aurinia saxatilis, Pulmonaria cevennensis, P. angustifolia, P. rubra, Trillium sp., Ajuga, Vinca minor, Allium giganteum, Waldsteinia ternata, Glaucidium palmatum, Hylomecon, and Stylophorum, among others. Pests/Problems: Eastern Tent Caterpillar, Lily-leaf Beetle, mosquitoes, black flies, and ticks continue to be the main problems. Soils are very dry and we have begun to irrigate turf and herbaceous borders.
Pioneer Valley Region (Amherst)
General Conditions: The unseasonably hot and dry conditions continued during this past reporting period across the Pioneer Valley. The weather during the first half of May has better resembled conditions we experience in late June and early July. High temperatures hovered from the mid-80s to low 90s and the dew points were just high enough at times to remind us of the muggy summer conditions yet to come. This shot of summer weather accelerated plant development to the point where some plants are actually flowering ahead of schedule (lilac, for example). This has created an explosion of spring color on the landscape with early and mid-season plants flowering together. The downside is that these tender flowering parts aren’t likely to hang around for long, especially with the lack of precipitation. After successive days of heat, on Tuesday 5/12 a cool front swept through the region bringing scattered rain and thunderstorms along with decidedly cooler air. The rain on 5/12 was the first measurable precipitation throughout most of the valley since 4/22, making it nearly three weeks of bone dry conditions. Yet, the rain received in scattered locations was barely enough to wash off the thick layer of green pollen coating most surfaces. Hampshire and Hampden Counties received a trace amount of precipitation, if anything. Franklin County was the recipient of several isolated cells that pushed through the valley late in the day but accumulations were still modest. According to the most recent U.S. Drought Monitor report (http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?MA), the entire state is now categorized as “abnormally dry”. Despite the dry weather, the mid to lower soil horizons are still moist. The upper soil surface has dried out but established trees and shrubs should be able to find enough water to satisfy their demands during this time. Lawn grass is still bright green and growing at a robust rate. But, we need a soaking rain to provide the upper fine root mass with badly needed water. For most of April plant growth and development was delayed because it just wouldn’t warm up. Next, plants developed at a rapid rate because it just wouldn’t cool down. Now, it appears we’ve returned to more seasonable conditions but it just won’t rain. For those that like complaining about the weather in New England, it’s been a good spring season. Red flag warnings continue to be issued throughout the northeast due to the gusty winds and lack of rainfall. To date, there have been no serious brush/forest fires in the valley. A frost warning was issued by the National Weather Service for the early morning hours of Thursday, 5/13. Areas of primary concern are higher elevations in the hill towns on the eastern and western sides of the valley. Pests/Problems: Recently planted (within the past 3-5 years) trees and shrubs should receive supplemental watering. Despite the dry weather, mosquitoes have emerged, especially along north-facing aspects. Remove any free-standing water in buckets, etc. to reduce potential egg-laying sites. There are a large variety of small, green caterpillars that feed on succulent leaves of deciduous hardwoods. Carefully scout young trees as regularly as possible to manage these pests. Rose slug sawfly larvae have begun feeding. Damage appears as scattered brown spots/blotches on developing leaves. The damage typically appears first on leaves shaded or close to the main stem. Regular applications of insecticidal soap will effectively control this pest before the damage becomes severe. Douglas-fir have flushed new growth, with needles 1/3 to 1/2 elongated and now is the time to treat for needle cast caused by Rhabdocline if this pathogen has been problematic in the past. Colorado blue spruce is beginning to flush new growth. Fungicide treatment for needle cast caused by Rhizosphaera should begin when the needles are half-elongated and again on labeled intervals if wet weather persists. Norway spruce is also producing new growth but they are highly resistant to needle cast and do not require chemical treatment under normal circumstances. Balsam fir are close to flushing new growth too but are probably another week away while white fir have started flushing. Spruce spider mites are active and the dry, warm weather has been ideal for their development. This pest was very damaging in 2014 and 2015 could be a similar story. There is an emerging pest of Norway spruce that has been recently reported throughout the northeast. The Norway spruce gall midge (Piceacecis abietiperda) is a small, fly-like insect that is native to Europe and has become a significant pest in recent years. The adult gall midges emerge in April and May (in some cases as early as March) and then mate and deposit their eggs mostly into newly developing shoots. In many cases, the eggs are laid under the terminal bud scales as the shoots are developing. The larvae burrow into this succulent tissue causing swellings to form under the bud scales. Less frequently, the swellings occur along shoots or near the terminal bud. Larvae develop and overwinter within the galls. Symptoms include deformed or bent shoots, swellings in nodes and premature needle shedding. This pest is known only on Norway spruce in both Europe and northeastern North America. The Norway spruce gall midge was first detected in Connecticut in 1983 and has been spreading rapidly since that time. It is most often found causing damage on large, specimen trees in landscape settings. There is only one other species in genus Piceacecis, the white spruce shoot gall midge (P. tsugae). This species attacks only white spruce (Picea glauca) and is native in North America.
Berkshire Region (Great Barrington)
General Conditions: The region experienced the Horticultural version of “Shock and Awe” this past week as temperatures soared well above normal, reaching 88º F at the Great Barrington monitoring site on May 10. The awe was manifested in the rapid blooming of many trees and shrubs. Crabapples dominate the display of bloomers in managed landscapes with lilacs following not far behind. The crabapple floral show is so impressive and widespread that this would have been the ideal year for a crabapple festival in the Berkshires. Other woody plants to come into bloom this past week include Carolina silverbell (Halesia tetraptera), Viburnum carlesii, Ohio buckeye (Aesculus glabra), dwarf fothergilla (Fothergilla gardenia) and Daphne × burkwoodii 'Carol Mackie'. Unfortunately, the heat brought the flowering phase for some trees such as shadbush (Amelanchier spp.) to a quick end. Precipitation continues to be a rare occurrence. Over the past 19 days, only 0.01 inches of rain has fallen. Red flag warnings have been commonplace in Berkshire County during that spell. The National Weather Service states that “Red Flag Warning means that dangerous fire weather conditions are expected due to the combination of gusty winds, low relative humidities, and dry fuels. Any fires that develop may quickly get out of control and become difficult to contain.” One such warning is in effect today, May 13. Soil moisture levels are low. Nevertheless, turfgrass growth has been good though some brown patches have become evident. Pests/Problems: The deleterious effects of winter continue to appear, often with odd leafing and flowering patterns. Most of the flowers on some flowering quince, as is the case with old varieties of Forsythia, appear only on the lower portions, that is, the portions which were below the snow level. Likewise, leafing on other shrubs is only at the lower levels, though the thumbnail test indicates some life left in the upper sections of the stems. It is best to wait a few more weeks before pruning back “apparently” dead shoots. Ticks, carpenter bees, mosquitoes, Eastern Tent Caterpillar (ETC) remain active. ETC larvae are about 1.25 inches in length. Lily Leaf Beetles are in the larval stage. Boxwood leafminers are pupating. Snails are feeding on lush herbaceous plant foliage.
Environmental Data
The following growing-degree-day (GDD) and precipitation data was collected for an approximately one week period, May 7 through May 13. Soil temperature and phenological indicators were observed on or about May 13. Total accumulated GDDs represent the heating units above a 50° F baseline temperature collected via our instruments for the 2015 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 |
GDD |
Soil Temp |
Precipitation |
|
Cape Cod |
87 |
159 |
61 |
0.04 |
|
Southeast |
84 |
157 |
71 |
0.15 |
|
North Shore |
79 |
158 |
60 |
0.01 |
|
East |
105 |
210 |
65 |
0.03 |
|
Metro West |
105.5 |
177.5 |
65 |
0.02 |
|
Central |
111 |
206 |
56 |
trace |
|
Pioneer Valley |
126 |
252 |
64 |
0.02 |
|
Berkshires |
122 |
205 |
60 |
0.01 |
|
AVERAGE |
102 |
191 |
63 |
0.04 |
|
n/a = information not available |
||||
Phenology
Phenological indicators are a visual tool for correlating plant development with pest development. The following are indicator plants and the stages of bloom observed for this period:
| 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. |
| Rhododendron carolinianum (Carolina Rhododendron) | begin | full | begin | n/a | begin | begin | begin | * |
| Spiraea x vanhouttei (Vanhoutte Spirea) | * | * | begin | * | begin | * | begin | * |
| Elaeagnus umbellata (Autumn-olive) | * | begin | begin/ full | * | * | full | begin/full | * |
| Syringa vulgaris (Common Lilac) | begin | full | begin/ full | full | begin | full | full | full |
| Cornus florida (Flowering Dogwood) | begin/full | full | full | full | begin/ full | begin/full | full | full |
| Rhododendron spp. (Early Azaleas) | full | full | begin/ full | full | begin/ full | begin/full | begin/full | begin/ full |
| Malus spp. (Crabapple) | begin | full | full | full | full/end | full | full/end | full |
| Cercis canadensis (Redbud) | begin | full | full | full | full | full | full | full |
| Pyrus calleryana (Callery Pear) | full | end | full | end | full/end | full | full/end | full/ end |
| Amelanchier spp. (Shadbush, Serviceberry) | full | end | end | full/end | full/end | end | end | end |
| Chaenomeles speciosa (Common Floweringquince) | begin/full | full | * | full | full/end | full | full/end | full |
| Rhododendron 'P. J. M.' | full | full/end | full | end | full/end | full/end | full | full |
| Prunus serrulata (Japanese Flowering Cherry) | full/end | full/end | full | end | end | end | end | end |
| Magnolia x soulangeana (Saucer Magnolia) | full/end | end | end | * | full/end | full/end | end | full/ end |
| Forsythia x intermedia (Border Forsythia) | full/end | full/end | full/end | end | full/end | full/end | end | full/ end |
| * = no activity to report/information not available | ||||||||
- CAPE COD REGION - Roberta Clark, UMass Extension Horticulturist for Barnstable County - Retired, 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
Decline of Norway spruce (Picea abies) caused by the Norway spruce gall midge (Piceacecis abietiperda). Several trees, ranging in age from 15- to >100-years-old at two sites in Vermont and New York. Other pests/pathogens are also involved in the dieback. The Norway spruce gall midge is native to Europe and was first detected in Connecticut in 1983. Symptoms include deformed or bent shoots, swellings in nodes and premature needle shedding. This pest is known only from Norway spruce in both Europe and northeastern North America.
Decline of Norway spruce (Picea abies) caused by the spruce spider mite (Oligonychus unuguis), needle cast caused by Rhizosphaera and stem cankering caused by Phomopsis. Increasingly, this is a common and destructive trifecta on spruce in New England. This particular tree is approximately 80-years-old and likely has been in decline for several years. While Norway spruce is highly resistant to Rhizosphaera, once it is weakened the pathogen can play an important role in decline. Phomopsis can be regularly found on declining Norway and blue spruce, causing tip blight on young shoots. Compacted soil, mowing injuries and girdling roots were predisposing stresses.
Volutella leaf and stem blight on English boxwood (Buxus sempervirens ‘Suffruticosa’. Multiple plants at various sites, ranging in age from 1- to 10-years-old. Browning/yellowing leaves, premature leaf shedding and shoot dieback present throughout the shrub canopy. Volutella buxi is a common and destructive pathogen of ornamental boxwood in the region. Lawn and overhead watering helped to facilitate disease development and spread.
Marginal leaf scorch caused by Colletotrichum and Phyllosticta on Rhododendron ‘Purple Passion’. One-year-old, nursery grown plants with browning leaf margins that developed over the past several weeks. Colletotrichum is the ubiquitous anthracnose pathogen capable of attacking dozens of woody plant genera. The shoots and roots were healthy and Phytophthora was not detected. Overhead watering was again to blame for spread of the pathogens.
Winter injury and foliar blight caused by Phyllosticta on American holly (Ilex opaca). The winter of 2014-15 was not kind to American holly and other evergreen shrubs. Multiple mature plants, all over 30-years-old, at three different sites exhibiting browning leaves with evidence of pathogen attack (see photos below). Phyllosticta creates abundant pads of tissue (known as pycnidia) that release large volumes of spores during wet and humid weather.
Suspected drought stress and stem cankering caused by Phomopsis on lilac (Syringa vulgaris). Shrub is approximately 25-years-old and has been present at the site for nearly as long. Stressful growing conditions along a sidewalk with droughty soils. Soil heating, radiant heat from the sidewalk and drought-stress from 2014 may have predisposed the shrub to attack by the opportunistic Phomopsis. An adjacent group of lilacs died two years ago from unknown causes.
For more detailed management information for woody plant diseases in the landscape, refer to UMass Extension's Professional Management Guide for Diseases of Trees and Shrubs.
Report by Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass Amherst.
Management Practices
Spring bulb foliage
As spring bulbs start to decline, it’s important to remember not to cut back the foliage. After blooming is complete the plants need to store food reserves in the bulb in order to bloom next year. This means that foliage needs to remain to allow for photosynthesis. It is ok to remove the spent flowers. Once the leaves naturally yellow and begin to dieback foliage can be removed (this may be around late June). Planting annuals round spring bulbs is a great way to hide the remaining bulb foliage.
Planting tips for shrubs and trees
The planting hole - Planting depth is very important – planting trees and shrubs too deeply can easily kill the plant. The hole should be only as deep as the root ball, ensuring that the trunk flare is above ground level (see photo at right). During planting, make sure the plant was not grown too deep and remove any soil/growing media as needed to uncover the trunk flare. Problems from planting too deep can include lack of oxygen to roots, root and trunk rots, and encircling roots that can girdle the plant. The hole should be dug at least three times the diameter of the root ball to allow for good root development.
Care in planting - If planting a B&B (balled and burlapped) plant, all visible rope or twine, burlap, and as much of the wire basket as possible should be removed after the plant has been placed in the hole. Check for and remove any encircling roots. If planting container grown plants, check for circling roots (especially at the bottom of the container) and remove the outer 1” of the root ball with a knife, saw, or pruners to encourage roots to grow outward. Backfilling with existing soil is recommended unless the existing soil is particularly poor (i.e. heavy clay). It is also not recommend to “tamp in” or compact the soil when backfilling but instead let water settle the soil.
Plant care during the growing season - Watering new landscape plants is extremely important during the first year, and longer for larger trees. Frequent, light irrigation is best during establishment (the first month) as most water uptake will be around the root ball. Deeper, less frequent, watering will be needed as the plant becomes established. Be familiar with your soil type; overwatering can be common and is especially bad in poor draining clay soils. It is best to check soil moisture frequently and water as needed. Also keep in mind that newly planted shrubs and trees can have very different water requirements than a newly planted lawn (trees and shrubs will likely be overwatered when irrigated the same as a lawn). Mulching can help maintain soil moisture, moderate soil temperatures, and protect plants from lawn equipment. Remember to keep the mulch away from the trunk - no mulch volcanoes!
Report by Mandy Bayer, Extension Assistant Professor of Sustainable Landscape Hortulculture, Stockbridge School of Agriculture, UMass Amherst.
Landscape Turf
Management Practices
It’s All About the Water
Different turf management programs have different approaches to water use. During most years in New England, less rainfall in the summer coupled with heat and high evaporative demand activate a natural tendency of turfgrass plants: dormancy. Dormancy can save management resources during high summer, and when approached properly turf areas typically recover satisfactorily when conditions moderate in late summer or early fall.
Since turf aesthetics and several functional aspects suffer when turf enters dormancy, summer irrigation to supplement natural rainfall is usually necessary in systems for which performance is a high priority (golf courses, sports fields, high-value ornamental lawns, etc). On the other side of the coin, irrigation is of little concern or perhaps not even possible in some lower maintenance systems (roadside turf, for example). Regardless of management level, there is growing motivation in recent years to reduce water use for turf maintenance to the lowest possible level. In some cases, water restrictions force the issue by physically limiting the amount of water available for irrigation, or rising costs impose actionable pressure on budgets.
Sometimes, however, Mother Nature steps in with a twist of her own. We have not even reached summer yet, and suddenly find ourselves in a difficult spot in terms of water this spring. While we were flush with moisture going into last winter and immediately following snow melt, things have quickly dried out and many parts of the state and region have had little in the way of measurable precipitation in over three weeks. The situation has been further exacerbated by hot weather in recent days coupled with seemingly constant breezy conditions.
The timing is really not great, as this period of the spring is critical for winter recovery, root development, and a number of key management activities. Regardless of the normal approach to water use in any given system, the following are reminders about the important role of water in some common spring practices. While in many years natural precipitation helps a great deal to support these activities with a little planning, intervention in the form of supplemental irrigation may be needed this spring to meet management goals.
Fertilizers – Water is necessary for release of nutrients from fertilizer materials, to support microbial breakdown for materials that require it, and for nutrient availability, mobility and plant absorption. Lack of moisture in conjunction with applications could result in problems such as insufficient turf response, uneven response, and undesirable carryover of material beyond the target period.
Pre-emergence herbicides – The vast majority of pre-emergence herbicides require watering-in in order to ‘activate’ the material, especially granular and on-fertilizer formulations. If water from irrigation or natural rainfall is not supplied in an amount specified on the product label, and within a reasonable time following application, reduced control or failure could result.
Grub control – As with pre-emergence herbicides, preventive grub control products whether chemical, biological or otherwise, also require watering-in to realize any chance of success. The grubs live below the surface of the soil, and a sufficient amount of water is necessary to carry the materials through the thatch and into the root zone to reach the grubs.
Turf planted last fall – Turf planted last fall, especially with the hard winter, is not yet well established. Recently planted areas are likely to be among the first to show stress these last few weeks, because their root systems are not fully developed (see photo above right). The spring is an important time for rooting prior to the stresses of summer, and ample moisture now will pay dividends during extended hot and dry periods in July and August.
Turf planted this spring – Widespread winter injury has led to a lot of repairs and re-planting this spring. Even if regular irrigation is not in the long-term plan, water is necessary during the establishment phase to promote seed germination or rooting of sod, to prevent seedlings or sod from drying out until they can 'stand on their own', and to enable rapid and effective establishment.
Report by Jason Lanier, Extension Educator, UMass Extension Agriculture & Landscape Program, UMass Amherst.
Additional Resources
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For a complete listing of upcoming events, see our Upcoming Educational Events page.
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
