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Landscape Message: Apr 17, 2015

Apr 17, 2015
Issue: 
5

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 April 24. 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: This reporting period started off chilly and damp, with daytime highs in the 40s F and a lot of drizzle and a few showers. Total precipitation was less than 0.5” but the overall effect was cold and damp. Conditions changed by Saturday the 11th, when the winds began to come from the Southwest. Sunny skies have prevailed since then, with the exception of 4/14, which was overcast, and temperatures have continued to be slightly above average, for a change. Daytime highs in the upper 50s F flirted with the 60º F mark. Plant development has responded to the more favorable conditions; hosta, daylily, and other perennials are beginning to peek out of the soil. Early Daffodils are beginning to bloom. Crocus, and snowdrops are in full bloom, with minor bulbs such as Chionadoxa, Siberian Squill, and Puschkinia beginning to bloom. ‘Jelena’ witch hazel is ending but ‘Arnold Promise’ is still in full bloom. Hellebores, both H. xhybridis and H. foetidus, are beginning to bloom. Spring heather is blooming. Pests/Problems: Winter damage is the most common problem in the landscape at this time. Many small shrubs were crushed under the weight of the snow and other shrubs and small trees have many broken or damaged limbs. Broadleaf evergreens are showing desiccation , especially on the parts of the plant that were above the snowline and subject to intense reflected light off of the snow, Boxwood, in particular, is in need of considerable pruning, but Rhododendron are also showing marginal burn of the foliage, a sign of desiccation. Needled evergreens such as arborvitae, hemlock, and yews are also damaged from winter burn. Dead tissue should be pruned out. Many smaller hydrangea that were planted last year are pushing up new growth from the base while the old canes look pretty dead. Wait to see if the canes might be viable before pruning.  Pollinators have become active. Solitary Bumble bees and Carpenter bees are active and Polistes wasps have been observed. Now is a good time to monitor for Eastern tent caterpillar egg masses on cherry and crabapple. Adult deer ticks are active. Use a repellent containing DEET when doing spring cleanups in brushy areas.

Southeast Region (Hanson)

General Conditions: What a difference one week and a few days of warm weather makes! Previous, cool weather has kept plant growth in check, but we are finally beginning to see some progress in plant development! However, development is behind previous years and even behind last year, which was very late. Hamamelis x intermedia ‘Jelena’, Hamamelis mollis 'Pallida', and Hamamelis x intermedia ‘Arnold Promise' continue to bloom and have been joined by: silver maple, Lonicera fragrantissima (Winter honeysuckle), Daphne mezereum (February Daphne), Salix sp. (pussy willow), Jasminum nudiflorum (winter jasmine), Helleborus niger, H. x hybridus, Corydalis solida, Galanthus nivalis (snowdrops), Iris reticulata, Scilla sibirica, Omphalodes verna, and crocus. Depending on location, area and cultivar, Red maples and Pieris japonica are beginning bloom or are in full bloom. The flower buds of Cornus mas (Corneliancherry Dogwood), Cornus officinalis, Corylopsis spicata, Stachyurus praecox, Abeliophyllum distichum (White Forsythia) and Helleborus foetidus, are developed and will probably open in the next day or two. Eranthis hyemalis (winter aconite) is past bloom. Lawns have finally started to green up and damage by snowmold and voles is evident. Now that the snow has melted (even in the shady areas), landscape cleanups have started in earnest. The landscapes are littered with broken branches and debris from the winter. Now is a good time to transplant trees and shrubs, remember to water after planting, even if rain is forecast. Hanson received 0.75 inches of rain last week. The spring peepers started “peeping” April 10th.  Pests/Problems: In Hanson, winter moth eggs are still reddish in color and have not started to hatch. As the eggs mature, they turn a light blue and just before hatch they will turn a dark blue-black. Staff at the UMass Amherst lab of Entomologist, Dr. Joe Elkinton, reported that, they “expect winter moth eggs to hatch at the end of this week or the beginning of next week”, depending on location. The staff also said that last year, most of the defoliation was along the coast and they are predicting that will likely be the case this year too. According to UMass, “Winter moth typically follows a two-year cycle (high year, low year, high year, etc.) and this year is scheduled to be a high year”, but this past fall the research staff did not see heavy flight, so they are predicting that it may not be such an extreme high this season. Dr. Elkinton’s staff started to see Bruce spanworm (BSW) hatch. Bruce spanworm is a native insect pest and looks very similar to winter moth. Honeybees, carpenter bees, solitary bees and hover flies have started to emerge and are actively seeking flowers. Unfortunately, there is not much out there right now for them. Overwintering wasps were also observed. Continue to monitor for Hemlock Woolly Adelgid (HWA) and cool-season mites. Deer ticks are active. To add another note regarding deer ticks, a rare virus called the Powassan virus is another disease transmitted by infected ticks. Although very rare, the Powassan virus can even be more dangerous than Lyme disease and can “cause serious nervous system disruptions, encephalitis, and meningitis”. From 2004 -2013, human cases of the virus have been reported in the northeast, including: New Hampshire (1), New York (17), New Jersey (1), Massachusetts (1) and Maine (2). Although it has been said many times, continue to take precautions against ticks, using repellents, etc. while working outdoors especially during landscape cleanups. Monitor for the fungal disease, black knot, on cherries and plums, and prune out and destroy the “knots” when found. Reports of deer heavily browsing plants continue to come in.

North Shore Region (Beverly)

General Conditions: The temperatures were in the 50s and 60s F most of the days during this reporting period. We accumulated 16 growing degree days in this period compared to only 3 degree days at Long Hill in the last reporting period. The soil temperature has also gone up to 45 degrees Fahrenheit from 37 degrees last week. We received approximately 0.28 inches of rainfall at Long Hill during this reporting period. The wind speeds were in the single digits except on Saturday April 11th when the average wind speed was over 13 miles per hour. The snow is now completely melted and most of the early spring flowering bulbs and other early spring flowering plants are either beginning to flower or they are in full bloom. The plants that are still in full bloom or coming into full bloom include: tommy crocus, snowdrops, puschkinia (Puschkinia scilloides), winter aconite (Eranthus hyemelis), glory of snow (Chionodoxa sp.) and white hellebores (Helleborous niger), goat willow (Salix caprea), Arnold promise witchhazel (Hamamelis x intermedia) and silver maple (Acer saccharinum). Plants beginning to flower include: Siberian Squill (Scilla siberica), February daphne (Daphne mezereum), white fragrant viburnum (Viburnum farreri 'Album'), purple hellebore (Helleborous orientalis x hybridus) and American filbert (Corylus americana).  Pests/Problems: After all the snow has melted a few shrubs such as lilacs are showing some signs of vole damage. Winter burn on rhododendrons, azaleas and box wood. There are leaf spots on azaleas and some rhododendrons and twig blights on junipers. Ticks are very active so take precautions when working outdoors.

East Region (Boston)

General Conditions: We have seen quite a change over this last week. We started the week (April 8th) with cool, cloudy, and windy conditions; light flurries during the afternoon. These below average conditions continued into Thursday (April 9th) as rain fell throughout the day and temperatures reached a mere 37º F. Rain continued into the morning of the 10th before a warm front moved in bringing seasonal temperatures. The first half of the weekend was seasonal with strong winds but by Sunday the winds had diminished, the sun was out and temperatures reached 69º F. Most of the remaining snow had melted; snow can only be found in areas with deep shade. Temperatures continue to be above average; reaching 71º F on the 13th. We gained 16 GDDs over the last week bringing us to 20 on the year. Grass is beginning to green up; buds are breaking and leaves are emerging on some shrubs. Things are happening in the landscape: numerous plants have suddenly popped into flower. Perennials in bloom: Asarum europaeum (European wild ginger), Eranthis hyemalis (winter aconite), Helleborus sp. (hellebore), Petasites hybridus (butterbur), Petasites japonicus (fuki), and Symplocarpus foetidus (eastern skunk cabbage). Bulbs in flower: Chionodoxa sp. (glory-of-the-snow), Crocus sp. (crocus), Iris reticulata (netted iris), Galanthus nivalis (snowdrops), Narcissus sp. (daffodils), Puschkinia scilloides (striped squill), and Scilla siberica (Siberian squill). Shrubs in bloom: Corylopsis coreana (winter hazel) and Stachyurus praecox (early stachyurus). The critically endangered and rare in cultivation Magnolia zenii (Zen magnolia) is in full bloom.  Pests/Problems: We are at 20 GDDs with minimal leaf emergence. Evidence of insect activity is minimal; bees have been spotted on many bulbs. Winter annuals continue to thrive. Early annual weeds are emerging. Lesser celandine (Ranunculus ficaria) is just beginning to flower. Maple (Acer) seedlings are germinating. Yellow flag iris (Iris pseudacorus) leaf blades have reached 6 inches in size. Allergy season has arrived; although the flowers may be visually insignificant, pollen of alder (Alnus), hazelnut (Corylus), juniper (Juniperus), poplar (Populus), and red maple (Acer rubrum) are in full bloom.

Metro West (Acton)

General Conditions: Spring is in the air! We’ve had a five day run of temperatures above 50º with a high temperature of 72º recorded on April 13th. Just to remind us that it’s still spring and not yet summer a low temp of 27º was recorded on April 11th. New signs of spring continue to reveal themselves daily. Peepers are out in force; frost is out of the ground and soils are dry enough to work; and in bloom are Acer rubrum (Red Maple), Adonis amurensis, Chionodoxa luciliae (Glory of the Snow), Cornus mas (Cornelian Cherry Dogwood), C. officinalis (Japanese Cornelian Cherry Dogwood), Crocus spp. (Crocus), Hamamelis spp. (Witchhazels), Crocus spp. and Galanthus nivalis (Snowdrops), Helleborous niger (Christmas Rose), Petasites japonicus (Japanese Butterbur), Scilla siberica (Siberian Squill) and Symplocarpus foetidus (Skunk Cabbage).  Pests/Problems: There is much work to be done in the landscape, whether it is pruning branches on shrubs or lower limbs on trees that are damaged and broken as a result of the weight of the snow from this past winter or from rodents chewing on their bark, repairing turf damaged by rodents or snow removal equipment and scattered woody debris down from strong winds.

Central Region (Boylston)

General Conditions: The return of warm weather since April 11th has all but eliminated the snow. Patches persist where it was piled high, and in deeply shaded nooks and crannies, but daytime temperatures in the 50’s and 60’s has even those patches on the run. Spring peepers and wood frogs were heard on Monday, April 13th for the first time this season. Many minor bulbs - Siberian Squill (Scilla sibirica), Glory of the Snow (Chionodoxa forbesii), Dwarf Iris (I. danfordiae and I. reticulata) and Fumewort (Corydalis solida) join Snowdrops (Galanthus sp), Crocus sp. and Winter Aconite (Eranthis hyemalis). The shoots of Bloodroot (Sanguinaria canadensis) are up though not quite blooming. The buds on White Forsythia (Abeliophyllum distichum) are beginning to show color as are those on Brouwer's Beauty Andromeda (Pieris ‘Brouwer’s Beauty’), Mountain Andromeda (P. floribunda) Winter Hazel (Corylopsis pauciflora) and Honeysuckle (Lonicera x purpusii). Witchhazel (Hamamelis cvs) continue to bloom profusely. Elms (Ulmus americana) are also in bloom Turf is beginning to green up and early cultivars of daffodils are blooming.  Pests/Problems: Mosquitoes are emerging and ticks are quite active. Vole damage is evident in turf and at the base of trees and shrubs. Additional damage to evergreen foliage is evident, and there is a great deal of cleanup to be done from the excessive snow and from plows.

Pioneer Valley Region (Amherst)

General Conditions: What a difference a week makes. On Wednesday, 4/8 a winter storm advisory was issued for much of northern and western portions of the Pioneer Valley. The following day, up to 0.5” of crusty, wet snow blanketed most of the valley. In previous years, we could indulge the beautiful contrast of flowering crocuses and pansies with a light covering of snow but not after this past winter. In addition to the snow, conditions were cold and raw with temperatures in the high 30s to low 40s and were coupled with the persistent spring winds that characterize the valley during this time of year. The tide began to turn on 4/9 and 4/10 when high temperatures reached the mid-50s. The system that brought snow turned to rain and some locations received upwards of 1” of precipitation over this two-day period. Conditions were still very windy with a maximum gust of 45 mph recorded at Barnes Airport in Westfield on Saturday, 4/11. But on Sunday, 4/12 spring arrived with high temperatures in lower 70s and we haven’t looked back since. High temperatures have remained in the upper 60s to low 70s and the long-term forecast calls for consistently mild and seasonable temperatures going forward. It wasn’t all good news though, as the National Weather Service issued a “red flag warning” on 4/15 which indicates that critical fire weather conditions are present. Abundant amounts of dry, desiccated organic matter paired with low humidity and strong spring winds can lead to rapid fire development in forests and fields. Pine, spruce and Douglas-fir buds are swelling and silver maple, red maple and locust are flowering. Soil temperatures have continued their upward trend with readings as high as the low 50s in locations with full sun.  Pests/Problems: 2014 was a big year for eastern tent caterpillar on cherry (Prunus). While not considered a major pest, now is the time to scout for the black-brown egg masses that encircle small twigs. Prune out this infested material and destroy it to reduce new infestations. Of far greater importance, now is also the time to inspect for gypsy moth egg masses in bark crevices. Remove and destroy these cream- to light brown-colored egg masses by whatever means possible. White pine weevil will soon be active, especially with temperatures now consistently above 60º F. Carefully scout the main leaders on white pine (Pinus strobus) and Norway spruce (Picea abies) for the brown-colored weevils. With the warm conditions, some fungal pathogens will become active soon. But the cool night-time temperatures will restrict the growth and development of most pathogens we consider problematic. With plants at least two weeks behind their normal development we don’t have to worry just yet about anthracnose, needle cast and foliar blight pathogens. Clean up and destroy fallen leaves that may serve as inoculum for common and troublesome pathogens like apple scab and maple/oak/birch/sycamore/elm anthracnose.

Berkshire Region (Great Barrington)

General Conditions: A very nice stretch of seasonable and above normal temperatures this past week has spurred numerous plants to burst into bloom. Snowdrops (Galanthus nivalis and G. elwesii) remain in bloom or are beginning to fade, depending upon exposure. Other spring bulbs in bloom are Crocus spp., Eranthis hyemalis, Chionodoxa luciliae, Anemone blanda, Scilla siberica, and Iris histriodes. Helleborus niger and H. orientalis are coming into full bloom and Hamamelis x intermedia cultivars continue to flower but are nearing the end of their bloom. Lawns are beginning to green up. Raking lawns now removes accumulated debris from winter storms but also removes accumulated thatch and frees grass blades matted down as a result of snow mold. However, as a word of caution, soil moisture levels are high in many areas, and excessive traffic on these lawns can cause serious soil compaction.  Pests/Problems: Snow mold on lawns, winter desiccation of needled evergreens, and innumerable broken branches on trees and shrubs remain as remnants of the brutal winter. Conifers near roadways are showing considerable browning of the sides facing the roads. A long stretch of white pines in the Becket section of the Mass Pike typifies such injury. Deer ticks (Blacklegged ticks) are active and there have been many reports of the ticks attaching themselves to people working outdoors or hiking in the woods. It is extremely important that precautions be taken to prevent tick bites. A relatively new (to the Northeast) and very serious disease, Powassan virus, is transmitted to humans by infected ticks. The Center for Disease Control reports that “approximately 60 cases of POW virus disease were reported in the United States over the past 10 years. Most cases have occurred in the Northeast and Great Lakes region.” For details of this disease, go to: http://www.cdc.gov/powassan/ . This is a good time to control magnolia scale by applying a dormant oil spray. The next opportunity to control the crawlers of this scale is in early fall. Carpenter bees are active.

Environmental Data

The following growing-degree-day (GDD) and precipitation data was collected for an approximately one week period, April 9 through April 15. Soil temperature and phenological indicators were observed on or about April 15. 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
(1-Week Gain)

GDD
(Total 2015 Accumulation)

Soil Temp
(°F at 4" depth)

Precipitation
(1-Week Gain in inches)

Cape Cod

14

18

48

0.47

Southeast

11

12

60

0.75

North Shore

16

19

45

0.28

East

16

20

55

0.59

Metro West

2

4

46

0.53

Central

13

14

42

0.70

Pioneer Valley

14

17

48

0.79

Berkshires

7

10

46

0.85

AVERAGE

14

18

48

0.47

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.
Magnolia stellata (Star Magnolia) * * * begin * * * *
Pieris japonica (Japanese Pieris) begin begin * begin * begin begin *
Cornus mas (Corneliancherry Dogwood) begin * * begin begin begin/full begin begin
Acer rubrum (Red Maple) begin/full begin/full begin full begin full begin/full begin
Acer saccharinum (Silver Maple) full full full full/end * full full full
* = 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 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

Management Practices

With the arrival of spring weather it’s important to think about the dos and don’ts of mulching. Mulch should be applied no more than 2-4” deep and should be kept away from the base of plants. Avoid spreading mulch over newly emerging perennials. When used appropriately mulch can provide many benefits in the landscape. Along with enhancing the aesthetics of the landscape, mulch can:

  • Increase soil moisture by reducing evaporation from the soil surface.
  • Suppress weeds from germinating at the soil surface (keep in mind that weed seeds can be blown onto the mulch surface and germinate there).
  • Increase soil organic matter (with decomposition), improve soil structure, improve drainage, and encourage mycorrhizal activity.
  • Help prevent mechanical damage from mowers and string trimmers that commonly occurs when grass grows next to tree trunks.
  • Moderate soil temperatures.
  • Provide erosion control.

Avoid mulch volcanoes! If mulch is applied in excess or carelessly problems can occur which include:

  • Mulch piled near the base of trees or shrubs can lead to increased moisture near the plant. This can lead to anaerobic conditions and rot.  With the occurrence of rot insect, fungi, and disease pressure increases.
  • Secondary root formation can occur because thick mulch retains moisture. These roots can slowly girdle the tree if not carefully removed.
  • Retained moisture in mulch can also mean that less water reaches the soil, decreasing soil moisture and increasing plant stress.

Sour mulch is another concern and occurs during production if mulch is piled too high. Large piles result in compaction and heating of mulch at the base of the pile; this results in anaerobic conditions and the buildup of organic acids which lower the mulch ph. These acids can damage plants and create a bad smell. Sour mulch can be improved by spreading it into a thin layer and watering heavily to leach away toxic acids. Sour mulch should also be moved away from plants to avoid damage.

Another consideration is the use of inorganic mulches, plastics, and weed fabric. Plastics and weed fabric are generally used as a base layer and are effective for weed control. They deteriorate over time, reducing their effectiveness. They can also be challenging if soil amendments are desired. Plastics should generally be avoided in landscapes due to decreased moisture and poor soil aeration. Stone or gravel can absorb and reflect heat, causing damage to plant material. Stone and gravel also do not provide the benefits of organic mulches in terms of improved soil moisture and structure.

Report by Mandy Bayer, Extension Assistant Professor of Sustainable Landscape Horticulture, 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