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Landscape Message: Mar 13, 2015

Mar 13, 2015
Issue: 
1

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.

Welcome to the first Landscape Message for 2015! The Landscape Message will be updated bi-weekly in March. The next message will be available on March 27. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.

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Scouting Information by Region

Regional Notes

Cape Cod Region (Barnstable):

General Conditions: 2015 started off in the teens on New Year's Day but temperatures rose and remained above freezing for the first three weeks of the month. Any precipitation during this period occurred as rain. It was warm enough on January 4th to accumulate 2 GDD, the only accumulation so far this year. 'Jelena' Witch hazel began to bloom on January 12th. A little "Bay Effects" snow fell on 1/13 but melted within a day or two. Conditions certainly changed towards the end of the month when the first blizzard of the year spanning 1/26 to 1/28 dumped 27" of heavy snow, accompanied by hurricane force gusts. A gust of 78 mph was recorded in Marstons Mills. The Cape hasn't seen the ground since that event. February started off with more snowfall but that changed to a sleet/rain event followed by a flash freeze. Temperatures have been well below average for the month of February, with a low of -2 occurring on 2/14 and a low of -5 occurring on 2/21. The second blizzard of the year occurred on 2/15 to 2/16 and left another 12" to 15" of snow on top of the previous accumulation. Winds gusted well into the 60+mph range. March came in like a lion, with another windy, snowy day. On March 5, another foot of snow came down. Temperatures began to moderate on March 9 and continue to be above freezing during the daytime to this point. Snow is beginning to melt but the Cape will not see the ground for a bit longer. Charles Orloff, director of the Blue Hills Observatory, recorded 85.5" of snow over the season so far at his home in Mashpee. Pests/Problems: It is too soon to gauge the effects of this harsh winter on plants. Those that have remained under the snow pack will probably be just fine, as snow acts as a great insulator and would protect against the extreme cold temperatures. Broken branches can be seen in the landscape due to high winds and heavy snow loads. Insect activity has been quiet with the exception of Collembola, snow fleas, which can be seen on objects in the landscape. They are harmless.

Southeast Region (Hanson)

General Conditions: Words like "epic", "record breaking", "historic" and "unprecedented" have been used to describe the winter of 2015, where record amounts of storms, cold and snow have resulted in one of the most miserable winters on record. Hanson received 76 inches of snow between January 23 and February 10. This past February was one of the coldest and snowiest on record. Several days in January and February saw temperatures in the single digits, including 0 degrees, with the coldest at -11 degrees. There were several snowy days in January leading up to the blizzard on January 26– 28, which resulted in approximately 24 inches of snow. This was followed by several snowy days in February with a storm on Feb. 15-16th which produced 13 inches of snow. Snow amounts varied around Plymouth County but most towns experienced 8-9 feet of snow from January 1 – March 7, and some towns near the coast experienced over 10 feet of snow. Hanson received just over 9 feet of snow. The weight of all this accumulated snow resulted in mailboxes being buried, impassable sidewalks, and roofs collapsing or leaking resulting from the ice dams that have built up. The extremely deep snow cover has also had a negative effect on wildlife that are scrambling to find food. Turkeys were seen walking down main streets in a few towns, and there have been increased reports of hawks feeding on small birds at feeders. The heavy weight of the snow has buried many plants and splayed, or pushed-out, the trunks and branches of small trees and shrubs like: Meserve hollies, hydrangeas, Taxus, bamboo, etc. In early to mid-January, before snow buried the plants, Hamamelis 'Jelena', Jasminum nudiflorum (Winter Jasmine) and Helleborus hybridus 'Jacob' were in bloom. Hamamelis x intermedia 'Arnold Promise', Hamamelis mollis 'Pallida', Cornus mas, Adonis vernalis (winter aconites) and snowdrops are often in flower at this time, but this is not one of those years, although 'Arnold Promise' and 'Pallida' buds just began opening late afternoon, March 11th. With over 2 feet of snow on the ground, it may be some time before the smaller plants appear. Broken branches and browning of some broad-leaved evergreens (Japanese and Koehneana hollies) has been observed. Browning of foliage due to salt-spray damage is noticeable on plants (hemlocks, white pine, evergreen euonymus, hollies, etc.) along roads and highways. Luckily, much of the snow that fell over the past months has been of the lighter-fluffier kind so there has not been as much damage from heavy wet snow, as seen in previous years and also very few power-outages. At this time, the ground remains covered with about 2 feet of snow. The past few days have been above freezing and snow has began to melt, melting the ice dams on roofs and reducing the high drifts and mounds of snow, but we have a long way to go. Pests/Problems:There are no significant insects to report at this time. Winter Moth will be the next big pest to be on the lookout for. Winter moth eggs usually hatch around the second week of April, sometimes earlier in warm, mild winters. According to staff at Dr. Elkinton's UMass Amherst, MA lab, "2014 winter moth caterpillar numbers were pretty low and most of the statewide defoliation was coastal (North Shore and coastal Cape Cod). Monitoring in the fall of 2014 showed "adult counts and egg-laying was up throughout the region, but likely stands out because 2014 spring numbers were so low." For spring 2015, Dr. Elkinton's lab will continue to monitor egg hatch. We don't know if the cold temperatures had any negative effect on winter moth eggs, which are fairly cold-tolerant. Dr. Elkinton's lab is conducting research on this. Stay tuned. The deep snow cover is great for tick survival so when the snow melts be on the lookout for deer ticks any time the weather is above freezing. Also, when the snow melts, we can monitor for vole and mouse damage which may be extensive.

North Shore Region (Beverly)

General Conditions: January was mild with an average temperature of 24 degrees Fahrenheit. The average high for the month was 32 degrees and average low was 16 degrees. The month of February was colder with average temperature of 16 degrees. The average high was 26 and average was 6 degrees. There is a deep layer of compact snow on the ground. In the last four days, temperatures have been above freezing and this has contributed to some snow melt on the sidewalks and roadsides. There has also been some reduction in the size of snowbanks. Witchhazel Hamamelis mollis 'Brevipetala' is beginning to bloom. Pests/Problems: There are some deer but they have not caused any damage yet because it has difficult for them to maneuver their way around the deep snow. Because of very high snow there may some damage by voles on young trees but it impossible to tell now until the snow melts. A pileated woodpecker, some hawks and skunks have been spotted in the area.

East Region (Boston)

General Conditions: We finished out 2014 with a wet and warm December. Temperatures ranged from 63.3º F to 12.7º F, averaging 36.9º F, four degrees above average and rainfall, for the third month in a row far exceeded expectations. Over the first week and a half, three large storms passed through the area, dropping an accumulated 5.54 inches of rain! These storms left mulch washouts throughout the grounds. We hit a high of 60º F on the 25th before temperatures dropped below freezing. By the end of the month, we had received 6.97 inches of rainfall. January's temperatures ranged from 52.25º F to -2.96oF and averaged 24.71 ºF. We received mostly precipitation and a few flurries over the first three weeks. It wasn't until the 24th that we received our first measurable snowfall – this was just the tip of the iceberg. That weekend storm was followed by a blizzard on the 27th which dropped 28 inches of snow and brought extremely cold conditions. By the end on the month, we had recorded 36.75 inches of snowfall. Total precipitation for the month was equivalent to 3.75 inches. February was not much kinder; we saw two major storms over the first two weekends, accumulating 42 inches of snow over the first 13 days, breaking the old snowfall record for the entire month of February. Most of us would have been content with breaking that record, but Mother Nature had other ideas. Finding places to put the snow was already a challenge and over the following weekend, another blizzard dropped an additional 16 inches of snow. The below average temperatures we experienced since January led to minimal snow melt as the 57 inches of snow received until that point during February on top of the 32 inches received over the end of January created unprecedentedly large snow banks . Due to the freezing temperatures, the snow was light and fluffy, making snow shoving and plowing somewhat more manageable. We hit lows in the negatives on five occasions and ended the month with an average temperature of 17.53º F (an average low of 7.49º F and an average high of 27.57º F). We set a new record for the number of consecutive days of below average temperatures. By the end of the month, we had received an additional 65 inches of snow and a total of 3.98 inches of rain equivalence. Seasonal temperatures returned on February 21st and on the 22nd we reached a high of 41º F, the warmest day of the year until that point. These warm and sunny conditions began to do their job: melting the snow. We welcomed meteorological spring on March 1st with almost three feet of snow still on the ground. Since then, these conditions have continued as the snow pack has been greatly reduced. On March 11th, we reached a high of 59º F, a comforting sign that spring will indeed arrive. Hamamelis mollis (Chinese witchhazel) is just about in full bloom!  Pests/Problems: Winter moth surveys conducted in mid-January revealed heavy egg-laying in isolated pockets in naturally wooded areas while counts were significantly lower in previously treated areas. At this time, rabbit damage is visible on many "lower" limbs of Rosaceous plants and other shrubs and trees throughout the landscape. Much of this damage is located higher up on the plant due to the excessive snowfall and higher snowpack. Despite the record snowfall received this season, the frigid temperatures resulted in dry, light and fluffy snow which did not accumulate in tree canopies – the majority of the trees in the collection have remained unscathed. Many shrubs may suffer the majority of the damage following these conditions. Warmer daytime temperatures , melting snow and additional precipitation has resulted in the compaction of snow and additional weight on already buried shrubs with limbs embedded in frozen snow/ice. We will have to wait until the snow melts to determine the extent of the damage. Mechanical damage from foot-traffic, snowshoeing, sledding, skiing and snow removal efforts, will undoubtedly reveal additional damage to smaller shrubs. Initial scouting of the collection has revealed desiccation damage to Ilex sp. (holly) and Mahonia sp. (Oregon grape). Buxus sp. (boxwood) did not fare well with the extreme temperatures we received; winter damage is evident as bark has split and is peeling off the plants.

Metro West (Acton)

General Conditions: Spring is just a week away and yet the ground is blanketed with up to 3' of snow in some areas. Recent warmer temperatures have helped reduce the snow cover and lessen the threat of any future flooding. Approximately 108" of snow has been recorded this winter thus far. A total of 45" of snow was recorded in the month of January and 55+" of snow was recorded in February. Our first snowfall occurred on November 14th with just a trace of snow recorded and our first measurable and shoveable snow event took place later that month on the 27th, Thanksgiving morning, with 4+" of snow recorded. Winter storm Juno hit the area on January 27th and 28th and brought with it strong winds and over 25" of snow and even deeper snow drifts in some areas. This storm seemed to set off a series of snow events including one for each of the three remaining days in the month of January and on fifteen out of the twenty-eight days in February. Fortunately for the metro-west area, the snow that fell was typically dry and light and easy to move, considering the quantity of it. Subzero temperatures, not recorded quite as frequently as snowfall were recorded on four days in January and eleven days in February with the lowest temperature of -16 recorded on February 24th. Pests/Problems: Time will tell what damage this winter caused. Already, we've seen and heard about the ice dams, roof collapses and frozen pipes brought on by the accumulation of snow and extreme cold temperatures. Mechanical, rodent and mammal damage to the landscape is anticipated to reveal itself as the snow melts. On the positive side, early Hemlock Woolly Adelgid counts have shown high mortality due to the sub-zero temperatures.

Central Region (Boylston)

General Conditions: The ground is covered with a deep blanket of snow. Temperatures above freezing for the past two days have contributed to a small reduction in the snowbanks.  The frozen ground beneath walks, roads and patios has heaved impressively creating hills and dales where the land was previously flat. Pests/Problems: Deer are extremely hungry and are having a difficult time maneuvering through the deep snow in search of food. Skunks and chipmunks are moving about in the recent warm temperatures and lengthening days.

Pioneer Valley Region (Amherst)

General Conditions: Unlike Worcester County and points eastward, the Pioneer Valley was spared some of the heaviest snowfall this winter season. The best example was winter storm Juno (1/27-1/28), which left more than 30" in some eastern Mass. towns but dropped only 4-12" across the valley. Another example was the 2/14-2/15 blizzard that left accumulations between 14-24" in eastern Mass. yet tallied less than 6" across most of Hampden, Hampshire and Franklin counties. That being said, 2015 has been very snowy in the valley and considerable accumulations resulted from a seemingly endless string of winter storms from late January through mid-February. Since these record-breaking storms, snowfall accumulations were rather modest, with most storms leaving only a few inches in accumulation. Yet, the arctic air masses that brought in the snow also ushered in record cold temperatures. According to the National Weather Service, most of the northeastern U.S. experienced its coldest February on record, with average temperatures 9-15 degrees below normal. At Barnes Airport in Westfield, minimum temperatures below zero were recorded on 12/28 days in February, which included a six-day stretch (2/13 to 2/18) with below zero minimums. An an extreme minimum of -14 F for the month occurred on 2/21. The past week has seen high temperatures in the upper 40s to mid-50s, giving everyone a serious case of "spring fever" even while several feet of snow lingers in many locations. The National Weather Service Eastern Region posted a very interesting article to their Facebook page regarding snow melt. Over the past several days, considerable volumes of snow seem to have melted. But, with the soil frozen, where has the water gone? While much of the roadside snow has transitioned to water and runoff into storm drains, the article outlines how much of the snow has simply compacted forcing lower level snow to reabsorb the water. Over time, the snow becomes "ripened", meaning it cannot hold any additional water. In some cases, snow can sublimate, and transition directly from solid state to water vapor. Regardless of how it melts, we can expect a very serious mud season and saturated soils once the thaw finally begins. At this point, soil thaw appears to be weeks away.  Pests/Problems: To date, no pest or pathogen problems can be reported due to the heavy snowpack and dormancy of trees and shrubs. Expect winter injury from extremely cold ambient air temperatures that combined with gusty winds to create wind chill values that exceeded -30 F. Rhododendrons, redbud, blue atlas cedar, and trees and shrubs on the northern edge of their natural range will likely suffer the most damage. In addition, recently planted trees and shrubs in exposed settings are also susceptible. When winter injury does expose itself this spring, dead branches and shoots should be pruned out to avoid colonization by opportunistic cankering pathogens. Depending on your location and past history, bark-chewing rodents like meadow voles may have caused damage to small-diameter trees and shrubs. During extreme cold and with heavy snow cover, these pests can cause considerable damage as they seek out alternative food sources. Only time will tell the extent of the damage.

Berkshire Region (Great Barrington)

General Conditions: Snow depth is currently at 15 inches at the Great Barrington monitoring site. The depth is slowly diminishing with mild temperatures of the past few days due to melting, evaporation, and compression. Soil beneath the snow is frozen and poses a problem since water from melting snow cannot seep into the ground. A potential for flooding or long standing water in low areas exists. Pests/Problems: Animal damage to landscape plants is not uncommon. Some deer browsing is apparent but not very extensive. A more common problem is girdling of stems of woody plants, especially higher up on the stems as rabbits and rodents walk across the top of the snow. It remains to be seen what damage to stems exists below the snow. Browning of the tips of evergreens , most likely due to desiccation, has been observed.

Environmental Data

The following growing-degree-day (GDD) and precipitation data was collected for an approximately 2 week period, March 1 through March 11. Soil temperature and phenological indicators were observed on or about March 11. Total accumulated GDDs represent the heating units above a 50° F baseline temperature collected via our instruments for the 2014 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 GROWING DEGREE DAYS Soil Temp (°F at 4" depth) Precipitation
Year-end accumulation for 2014 Current accumulation for 2015 Since 1/1 Since 3/1
Cape Cod
2708

2

frozen

9.20" rain eq.
(70" snow)

2.63" rain eq.
(16.5" snow)
Southeast
2623

1

frozen

8.85" rain eq.
(103" snow)

1.10" rain eq.
(9.0" snow)
North Shore 2499 0 frozen 6.23" rain eq.
(86.3" snow)
0.49" rain eq.
(3.6" snow)
East
2815

0

frozen

8.33" rain eq.
(104.25" snow)

0.60" rain eq.
(2.5" snow)
Metro West
2286

0

frozen

8.37" rain eq.
(104" snow)

0.50" rain eq.
(3.8" snow)
Central
2288

0

frozen

8.37" rain eq.
(79" snow)

0.55" rain eq.
(61.8" snow)
Pioneer Valley
2744

0

frozen

4.91" rain eq.

0.24" rain eq.
Berkshires
2139

0

frozen

6.11" rain eq.
(61.8" snow)

0.51" rain eq.
(5.6" snow)
AVERAGE
2513
0
frozen
7.55" rain eq.
0.83 rain eq.

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.
Hamamelis x intermedia (Witchhazel hybrids) begin begin begin begin begin * * *
* = no activity to report/information not available
  • CAPE COD REGION - Roberta Clark, UMass Extension Horticulturist for Barnstable County - Retired, reporting from Barnstable.
  • SOUTHEAST REGION  - Geoffrey Njue, Green Industry Specialist, UMass Extension, reporting from Beverly.
  • SOUTHEAST REGION (Hanson) - Deborah Swanson, UMass Extension Horticulturist for Plymouth County - Retired, reporting from Hanson.
  • 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

Winter plant injury

Winter plant damage, such as broken branches, may already be apparent, but warming temperatures can contribute to other forms of winter plant injury. Some damage will only become visible when plants begin to leaf out in the spring.

  • Winter burn and frost cracks - Winter burn is the result of rapid temperature changes that occur when there is daytime warming and nights are still cold. This injury is most common on the south side of plants because the sun reflects off of the snow warming the plant greater than ambient temperature, leading to an amplified day to night temperature swing. The extent of winter burn damage can be variable; if buds have not been damaged recovery may be possible. Similarly, frost cracks occur in trees when bark and wood expands due to warming by the sun but temperatures remain cold. When no longer exposed to the direct light of the sun, the temperatures drop and the bark contracts before the inner wood. This causes the bark and the wood beneath it to crack, often resulting in a loud pop. These cracks close during warmer weather, but can open again in subsequent winters. They should be monitored for disease or insect damage in the warmer months.
  • Desiccation injury - Drying of evergreens is common in late winter and early spring. Winds and sunny days increase transpiration and frozen ground prevents sufficient water uptake from the soil. Desiccation can result in browning of needle tips or leaf scorch when injury is minimal, browning of leaves and needles when damage is moderate, and necrosis and defoliation if injury is severe.
  • Salt damage from de-icing – Salt damage on evergreens can look very similar to winter burn; however, the damage is usually on the side of the plant closest to the roadway or sidewalk. Foliar, bud, and small branch damage can occur when plants are sprayed by vehicles with snowmelt containing dissolved salts. Snow cover can help protect plants from direct spray from the road. Runoff containing salts from treated areas can also lead to salt stress injury for plants not directly next to roads and walkways, because sodium and chloride are taken up instead of necessary soil nutrients. Salt damage on deciduous plants may not be evident until later in the spring. Flower and leaf buds facing the road may have been killed or are delayed to leaf out/bloom compared to buds on the opposite side of the plant. Selective pruning will be necessary in the spring to remove severely damaged branches. Salt that accumulates close to plants can also absorb water that would be taken up by the roots leading to dehydration of and injury to the root system.
  • Frost heaving – Freezing and thawing cycles can lead to shallow rooted plants and plants that haven't been mulched being lifted from the ground, leaving them unprotected from cold temperatures, frost, and wind. It is important to replant these plants as soon as the ground allows.
  • Animal damage – Damage to landscape plants from rodents, rabbits, and deer can be common at this time of year with much of the natural vegetation is covered by snow. Common signs of animal damage include defoliation (especially of lower branches), girdling of stems or branches, and chewing damage. The extent of the damage will determine the overall impact on plant health with extensive chewing and girdling leading to significant damage or death of the plant.

Report by Mandy Bayer, Extension Assistant Professor of Sustainable Landscape Hortulculture, Stockbridge School of Agriculture, UMass Amherst.

Landscape Turf

Management Practices

Wait and See

With warming temperatures this week it would seem that we are finally getting into the home stretch of one of the fiercest winters in recent memory. In case you spent the winter in some tropical setting (if so, hats off), the weather of the last couple months featured just the sort of tests that push plant material in our turf and landscapes to the limit - frequent heavy snowfalls, high winds, and intensely bitter cold.

With record shattering snowfall amounts, especially in the Eastern portions of Massachusetts, it will still be a bit yet before we learn exactly the kind of shape that our turf is in. On the plus side, snow is an excellent insulator for turf, and we have had an extended period of snow cover that was present through much of the severe cold thus far.  Snow helps to buffer against extreme temperature fluctuations, and can help to prevent mid-winter de-acclimation in the event of a 'January thaw' situation (fortunately not a big factor in our region this winter). A snow cover also provides a barrier against desiccation injury from drying winter winds and very low dew points.  Drawbacks of prolonged snow cover, however, include increased incidence of snow molds and damage from critters such as voles that have a field day under the protection that snow provides.

A point of concern is the transition into winter, and the fall hardening period could have been a little better. We had mostly great grass-growing weather in September and October and started on a nice gradual decline toward winter dormancy in November. After a brief taste of winter around Thanksgiving however, December was rather mild, especially towards the end of the month. In fact, temperatures touched 60º in some locations on Christmas Day, soon after which we plummeted into the deep freeze.

Free water at the surface and in the upper soil profile can promote hydration of the vital turfgrass crown, especially in conjunction with milder temperatures, which sets up grasses for low temperature kill when temperatures drop off.  Precipitation in October was 3+ inches above average in many locations, 2+ inches above average in November, and 3+ inches above average in December, so the there was plenty of moisture to go around.  Perennial ryegrass would be the most prone to injury in such a scenario, especially in low spots and poorly drained areas.

Another source of anxiety is widespread ice cover. Rain and wet snow the first week of January was quickly followed by sub-zero cold, leading to ice formation in many locations. Lasting snow fell shortly thereafter, and along with consistent cold helped to preserve the ice.  Ice cover at the UMass Joseph Troll Turf Research Center in South Deerfield, for example, has exceeded 65 days and counting. The main mechanism of injury under ice is anoxia and suffocation due to inhibition of gas exchange, with low-mown Poa annua normally being the most susceptible and creeping bentgrass and Kentucky bluegrass often faring much better.

While everyone speculates, winter injury to turf is a complex and variable problem so it is impossible to precisely gauge the extent until the snow recedes and growth begins… and we're not quite out of the woods yet.  A steady warm up is what we're looking for - spring thawing followed by a cold spell can doom grasses that have come through previously unscathed, especially when moisture is plentiful as it promises to be this spring.  Again, Poa annua, perennial ryegrass and plantings from last fall are particularly at risk from late cold; thankfully the latest forecast looks moderate.

If you can't wait for snow/ice melt, some sampling might provide some insight into the status – cut holes in the ice and check for sulfur or rotten egg odors and/or pull some plugs, pot them up inside, and watch for signs of life.  At the very least, it might help with planning ahead.  Aside from some snow mold, current observation of the few melted areas in the Pioneer Valley is mostly encouraging.  One certainty right now is that a busy spring is on the horizon.

Report by Jason Lanier, Extension Educator, UMass Extension Agriculture & Landscape Program