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 bi-weekly July through September. The next message will be available on September 19. 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: The month of August was generally below average for temperatures, with most days averaging in the mid-70s F with cool, pleasant nights more reminiscent of fall than an August summer night. September has seen a return to hot and humid weather, with daytime temperatures in the 80s F and with very uncomfortable dew points, making working outdoors unpleasant. It continues to be painfully dry here on Cape Cod. With the exception of the 1" that fell overnight on 8/31, there has not been any appreciable rain since 0.8" fell on 8/13. Soils are very dry as we move into peak fall planting time. Hydrangea paniculata bracts are turning mauve-pink, Heptacodium micomioides is beginning to bloom, and Chrysanthemums are appearing at local garden centers. Unirrigated lawns are turning brown. Pests/Problems: The major problem at this time is the continued lack of rainfall over the region. This has been the trend since the beginning of May and many plants are showing signs of water stress. Marginal browning of foliage is common on woody and herbaceous plants. Many perennials and annuals that haven't been watered regularly go past bloom quickly and look unthrifty. Lawns without automatic irrigation systems are brown. Be sure to advise clients without irrigation to water landscape plants deeply once or twice a week, especially broadleaf evergreens. For fall plant installations, water will be critical for good establishment going into fall and winter.Wooly Bear caterpillars can be seen crawling about. Swallowtail butterflies are quite active but Monarch butterflies are slow to appear. Bumble bee, honey bee, and various species of wasp and hornet colonies are all at their peak size and can become aggressive if disturbed. Stink bug adults are present on foliage of various perennials. Sunflower moth caterpillar continues to damage cones of Echinacea, Rudbeckia, and Heliopsis. Tussock moth caterpillars have been observed. Alternaria leaf spot is prevalent on Zinnia. Powdery mildew is on many susceptible hosts, such as Lilac, Phlox, and Squash.
Southeast Region (Hanson)
General Conditions: Earlier in the past two weeks, daytime temperatures were in the 70's with night time temperatures in the 50's giving a feeling of fall. That changed this past week where temperatures started to show up in the mid-high 80's and it became very humid. Hanson received 0.40 inches of rain over the past two weeks and soils are very dry. Clerodendron trichotomum, Rose-of-Sharon, landscape roses, Campsis radicans, Hydrangea paniculata, butterfly bush, Sedum sp., ornamental grasses, Japanese Anenome, perennial hibiscus, Phlox paniculata, Rudbeckia trilobum, Rudbeckia 'Herbstonne', Rudbeckia fulgida 'Goldsturm', Rudbeckia subtomentosa 'Henry Eilers', Joe-pye-weed, Perovskia atriplicifolia (Russian Sage), Caryopteris divaricata, Corydalis lutea, Coreopsis tripteris, Coreopsis 'Harvest Moon', Echinacea purpurea and hybrids, Physostegia, Chelone, Helianthus 'Lemon Queen', Heliopsis 'Summer Sun', Hosta plantaginea and other late blooming Hosta and Lobelia cardinalis, L. syphilitica and Lobelia hybrids. Pests/Problems: Dry soils may well be the main cause for landscape concern over the past two weeks, with many plants showing signs of drought stress including: wilting,premature leaf drop, marginal leaf necrosis and premature fall color. Many unirrigated lawns that looked green and great most of the summer are now turning crispy brown and are appearing drought-stressed. Many towns have water bans in place and deep irrigation of landscape plants can be challenging. Remind clients to water high value trees and plants and also those tree and shrubs that were planted this season or were damaged or defoliated by winter moth caterpillars last spring. The following insects continue to be active: Pieris and other lacebugs, dogwood sawfly, red-headed pine sawflies, earwigs, hibiscus sawflies, boxelder beetles, wasps, annual cicada, slugs, spider mites, leafhoppers, snails, biting flies, katydids, cicada killing wasps, ticks and mosquitoes. Wasps and hornets and their nests are very prevalent this season! Be on guard and observe an area before digging or pruning. Giant tar spot continues to show up on Norway maple and the spots are now very large and evident. Powdery mildew is noticeable on many plants, especially susceptible garden phlox. Crabgrass, clearweed, Japanese knotweed, goldenrod, ragweed, and jewelweed are all flourishing. Deer are browsing hosta, tomato plants, and cucumber plants along with anything else that appeals to them.
North Shore Region (Beverly)
General Conditions: We had dry and sunny weather on most days in the last two weeks. Temperatures were relatively mild for this time of the year with day temperatures in the 70s and low 80s, and night temperatures in the 50s and low 60s. Wareham received only 0.23 inches of rainfall in the last two weeks. Non-irrigated turf and garden plants are showing signs of water stress. Remind clients to continue to water garden plants. Plants providing color in the landscape include Rose-of-Sharon, Panicle Hydrangea, Achillea (Yarrow), Astilbe spp., Coreopsis, Echinacea (Coneflower) Hemerocallis spp. (Daylily), Hosta spp., and Rudbeckia 'Goldsturm' (Black-Eyed Susan). Pests/Problems: Some trees and shrubs are starting to show signs of summer stress in the form of leaf spots, foliar blights, and general dieback and decline. Goldenrod and ragweed are blooming on roadsides and in some landscapes. Mosquitoes are still active especially at dusk and dawn.
East Region (Boston)
General Conditions: Late August felt like an early arrival of fall – conditions changed. We gained 259.5 GGD's over the past two weeks. It has been hot and humid with very little precipitation. We had a minimal amount of precipitation in August amounting to approximately 1.78". Over the last week of August and the first two days of September we received less than 0.5" of precipitation. Pollinators are busy visiting several plants in flower including; Caryopteris sp. (bluebeard), Clematis hercleifolia (hyacinth flowering clematis) and Rhus chinensis (Chinese sumac). Aster pilosus (fall aster) is adding color to the woodland understory. Acer rubrum 'Schlesingeri' (Schlesinger red maple) is showing its typical early fall color. Snapping turtles hatched on August 29th and were observed making their way to the ponds. Pests/Problems: Lack of precipitation has become a concern. Recent plantings require supplemental irrigation. Water stress is visible on Acer sp. (maples), Cercis sp.(redbud), Cornus sp.(dogwood) and Cercidiphyllum sp. (katsura). Many other mature specimens are also showing signs of drought. Ragweed (Ambrosia artemisiifolia) continues to produce abundant amounts of pollen. Ground nests of wasps are extremely active and becoming problematic in the landscape.
Metro West (Acton)
General Conditions: Despite the recent rains, soils remain dry. The Acton area received a total of 0.99" of much needed rain and gained 253 growing degrees over the past two weeks. The Metro West area received a total of 2.88" of rain for the month of August, falling short of 3.72", the thirty year rainfall average for the month. Woody plants seen in bloom this week are Buddleia spp. (Butterfly Bush), Clethra alnifolia (Summersweet Clethra), Hibiscus syriacus (Rose-of-Sharon), Hydrangea paniculata and its many cultivars including 'Tardiva') and Rosa 'Knockout' (The Knockout family of Roses). Woody vines in bloom are: Campsis radicans (Trumpet vine) and Clematis spp. (Clematis). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Astilbe spp. (False spirea), Aster spp. (New England Aster, New York Aster, Smoother Aster, White Wood Aster), Calamagrostis acutifolia 'Karl Foerster' (Feather Reed Grass), Cassia marilandica (Wild Senna), Chasmanthium latifolium (Northern Sea Oats), Chelone lyonii (Pink Turtlehead), Coreopsis verticillata (Threadleaf Coreopsis), Daucus carota (Queen Anne's Lace), Echinacea purpurea(Coneflower), Eupatorium purpureum (Joe Pye Weed), Hosta spp. (Plantain Lily), Liatris spicata (Spike Gayfeather), Lobelia cardinalis (Cardinal Flower), Macleaya microcarpa (Plume Poppy), Malva alcea 'Fastigiata' (Hollyhock Mallow), Miscanthus sinensis (Maiden Grass), Patrinia gibbosa (Patrinia), Pennisetum alopecuroides 'Hameln' (Dwarf Fountain Grass), Phlox carolina (Carolina Phlox), C. paniculata (Phlox) and its many cultivars, Platycodon grandiflorus (Balloon Flower), Rudbeckia fulgida 'Goldsturm' (Black-Eyed Susan) and Solidago spp. (Goldenrod). Pests/Problems: A total of three Asian Longhorned beetles have been captured within the Worcester County ALB regulated area. One was captured at large and two were caught in traps, all within the regulated area. Continue to check your trees for signs of the beetle including oviposition sites, frass, exit holes, weeping and maturation feeding and don't forget to look for the beetle. Monitor the 13 host genera which are: Acer (Maple), Betula (Birch), Ulmus (Elm), Salix (Willow), Aesculus (Horsechestnut), Fraxinus (Ash), Platanus (Plane Tree), Populus (Poplar), Celtis (Hackberry), Sorbus (Mountain Ash), Albizia (Mimosa), Cercidiphyllum (Katsura) and Keolreuteria (Golden Raintree).
Central Region (Boylston)
No report available this week.
Pioneer Valley Region (Amherst)
General Conditions: Summer has returned to the valley in a big way over this past reporting period. High temperatures in the upper 80s to low 90s with high humidity have sent the heat index soaring into the upper 90s. These conditions are in stark contrast to the first three weeks of August, when temperatures were unseasonably cool throughout the region. In addition to the heat and humidity, it's also been quite dry in the Connecticut Valley over the past several weeks. Scattered thunderstorms across the region have provided Franklin and Hampden County with some modest rainfall totals over the past two weeks, while most of Hampshire County has missed out on the rain. If we remove the deluge of rain the region received on 8/13 from the total precipitation in August, this eighth month of the year was dry, with only 1.2" recorded at Barnes Airport in Westfield. Even when we include the 13th in the discussion, there's been little precipitation capable of watering woody plants for several weeks now. Yet, even with the lack of rainfall, soil moisture at depths deeper than 6" remains good and established trees and shrubs should cruise into autumn with minimal, if any, water-related stress. In higher elevations, such as the foothills of the Berkshires, sugar and red maples are starting to exhibit fall colors. In some cases, these are stressed trees but others appear relatively healthy. Pests/Problems: Many trees and shrubs are showing the wear and tear of the growing season with foliage exhibiting insect feeding damage, leaf spots and blotches and on sites with excessively drained soils, drought stress. Many of the typical foliar pathogens are fully developed right now and include: apple scab, cedar-apple rust, tar spot of maple, purple eye leaf spot of maple, guignardia leaf blotch of horse chestnut, and anthracnose blights. Because of the dry conditions, many wood-decaying fungi are not producing fruiting bodies. But, continue to monitor trees suspected of being infected by root and butt rot fungi. Now is the time to examine cherry and crabapple for egg masses of eastern tent caterpillar, which appear as shiny black masses, clustered on small branches. Populations were high in 2014 and the pest should be abundant again next year. We will soon be entering an ideal period for treatment of hemlock woolly adelgid on affected hemlocks. While this pest suffered high mortality rates from last winter's cold temperatures, it won't take long for populations to bounce back. Oak leaf skeletonizer has also been abundant around the valley and the treatment window is quickly closing.
Berkshire Region (Great Barrington)
General Conditions: After a summer of mostly sub-normal temperatures, the past recording period has been characterized by above normal temperatures and high humidity, two conditions which favor the development of plant diseases, especially foliar diseases. Rainfall has varied considerably from one end of the county to another. During the past two weeks, a little over a half inch was measured at the Great Barrington monitoring site. Rainfall amounts were quite varied with Pittsfield recording three times the amount measured in Great Barrington. Such patterns are typical of summer storms. Soil moisture levels are low to moderate, depending on locale. Some premature fall color is apparent, especially on red maples on wet sites. This is not unusual; however premature fall color on trees and shrubs on well drained sites could be an indicator of a problem. Woody plants showing pre-mature color change or leaf drop should be carefully examined. Often the problems are environment, structural or culture related, e.g. poor drainage, girdling roots, deep planting. It may take several years for symptoms to become apparent and often it then is too late to do anything about it. Pests/Problems: Sooty mold was observed on foliage of magnolia and was related to infestation by Magnolia Scale. The scale is now in the crawler stage and may be controlled with an application of summer horticultural oil. Sooty mold was also seen on leaves of tulip trees (Liriodendron tulipifera) but was related to presence of aphids. Numerous lady beetles were seen on the trees and should help in management of the aphid infestation. Euonymus Scale crawlers are active at this time. Another scale found while scouting was the Elongate Hemlock Scale which was causing yellowing, browning, and needle drop on infested hemlocks. Other insects still active included Oak Leaf Lacebug, adult of Locust Leafminer, and stink bug nymphs. Basil downy mildew is pervasive and was found on every sweet basil checked at several locations. Tar spot on Norway maple was one of many leaf spot diseases that are causing pre-mature yellowing and/or leaf drop on a variety of trees. Powdery mildew is common on phlox, lilacs, and Physocarpus. Aggressive wasps, carpenter bees, mosquitoes, ants, slugs and snails are still plentiful.
Environmental Data
The following growing-degree-day (GDD) and precipitation data was collected for an approximately 2 week period, August 21 through September 3. Soil temperature and phenological indicators were observed on or about September 3. 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 |
GDD |
GDD |
Soil Temp |
Precipitation |
|
Cape Cod |
386 |
2147 |
75 |
1.00 |
|
Southeast (Wareham) |
235 |
1936 |
73 |
0.23 |
|
Southeast (Hanson) |
263 |
2139 |
76 |
0.40 |
|
East |
295.5 |
2241 |
76 |
0.48 |
|
Metro West |
253 |
1977 |
75 |
0.99 |
|
Central (Boylston) |
n/a | n/a | n/a | n/a |
|
Pioneer Valley |
287 |
2246 |
78 |
0.70 |
|
Berkshires |
295 |
1795 |
70 |
0.68 |
|
AVERAGE |
288 |
2069 |
74 |
0.78 |
|
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. (Wareham) | S.E. (Hanson) | EAST | METRO W. | CENT. | P.V. | BERK. |
| Heptacodium miconioides (Seven-Son Flower) | begin | * | * | begin | * | * | begin | * |
| Clematis paniculata (Sweet Autumn Clematis) | full/end | full | begin | begin/full | begin | * | full | begin |
| Sophora japonica (Japanese Pagodatree) | full/end | * | end | end | full/end | * | end | full |
| Polygonum cuspidatum (Japanese Knotweed) | full | full/end | full | full | full | * | full | full |
| Vitex agnus-castus (Chastetree) | full | full/end | * | * | * | * | 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 (Wareham) - Geoffrey Njue, Green Industry Specialist, UMass Extension, reporting from Wareham.
- 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 (Boylston)- 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
Insects
Fall Webworm caterpillars should be winding down now and may be finished in some areas. This pest has an extended deciduous host range that includes oak, maple, crabapple, birch, lilac, and others. This pest is thought of primarily as an aesthetic concern and not so much as causing actual damage to the plant.
Hibiscus Caterpillar remains actively feeding, primarily on perennial hibiscus and Rose-of-Sharon (Hibiscus syriacus) in Massachusetts. If necessary, a spray of a Spinosad product should be effective.
Red-headed Pine Sawfly is active, primarily on Mugo pine, and other two and three needled hard pines in MA. It can feed well into October, if temperatures remain mild. This yellow caterpillar, with obvious rows of black dots and a rust-colored head capsule, makes it easy to identify this pest in the field. If found in small numbers, they can be removed and destroyed by hand; this pest feeds in tight clusters on individual branches. This pest can cause severe defoliation if left untreated. A product that contains Spinosad works well on the larvae of all ages.
Dogwood Sawfly is active. Monitor host plants and inspect foliage, including underneath, for the larvae, which are often covered with a white pubescence that makes them appear as a bird dropping on the foliage. Typical of most sawflies on deciduous host plants, this sawfly feeds from the margins of the foliage inward towards the main vein of the leaves. Usually, the main vein is not consumed. Spinosad products will work well at this time. Host dogwoods include, but are not limited to: Osier dogwoods, gray dogwood, Cornus mas, Cornus controversa and others. This pest can feed well into October, if temperatures remain mild.
Japanese Beetle activity is coming to an end. However, continue to monitor susceptible plants and if controls are necessary, many of the pyrethroid insecticides are labeled for this pest. Read labels carefully in order to choose the best one for the particular site and host plant.
Viburnum Leaf Beetle adults are still actively feeding, mating and depositing eggs in terminal shoots. Monitor susceptible viburnum species and treat if necessary with a registered product labeled for this pest; in general, it is usually a pyrethroid. This pest is capable of causing much defoliation late in the growing season, if left untreated. Where population numbers are high, plants may be completely defoliated by now.
Ticks remain very active. Take extra precautions when working in tick habitat to protect oneself from contracting Lyme Disease. If infection is suspected, seek medical advice immediately.
Hymenoptera (bees, wasps, hornets) often come into increased contact with humans starting around this time of year and extending into the fall and reports from the field indicate high numbers this year. Many of these insects rely on flowers or other natural sweet attractions, and are finding that these sources are now in low numbers. Humans with food or sweet smelling drinks, etc. can become a great attraction for these hymenoptera at this time thus making them a nuisance. Also, most yellowjacket species make their nests underground and by this time of the year population numbers can be quite high (more than 1000 wasps). Should one accidentally dig into or step on one of these nests, it is highly recommended that you vacate the area immediately to avoid multiple stings.
Asian Longhorned Beetle adults are most prevalent in MA during August and into early September. Be vigilant for new finds. To see detailed images of the various life stages, telltale damage, and how to report new finds in MA visit: http://massnrc.org/pests/albreport.aspx
Lacebug Damage can become quite severe at this time if left unchecked. Host plants that grow in sunnier locations can especially sustain unacceptable levels of feeding damage in the form of very chlorotic foliage. In general, lacebugs thrive during the hottest and driest times of the year: host plants lose the ability to outgrow new damage, natural control agents become less active, and activity and reproduction of lacebugs becomes accelerated. Common host plants for lacebugs in MA include: azaleas, rhododendron, and Japanese andromeda. This summer was not as hot and dry as most summers in MA but lacebugs are still quite active. Systemic Imidacloprid or a spray of horticultural oil at the summer rate (and targeted to the foliage undersides) can be effective.
Hemlock Woolly Adelgid remains dormant on the twigs of host plants settled there near the base of the needles. Currently, they are second instar nymphs that are flat, black, oval and have a small ring of white fringe (wax) around their bodies. Now is a good time to inspect for the level of infestation and to treat with horticultural oil at the summer rate, when weather allows. These dormant nymphs will not awaken until around mid-October to resume feeding but they can be treated now if deemed necessary.
Warm-Season Spider Mites, such as the Two-spotted Spider Mite, remain very active on a variety of host plants. Monitor for chlorosis and the actual mites and treat if necessary.
Cool Season Mites such as the Spruce Spider Mite will resume activity soon. If fall weather remains mild well through October, continue to monitor for their build up in numbers. A spray of horticultural oil at the summer rate can provide adequate levels of control if applied when weather conditions are conducive to such sprays.
Fall House Invaders, such as Ladybugs, Western Conifer Seedbugs, Boxelder Bug, Brown Marmorated Stinkbug, and others are not yet attempting to seek shelter for the winter but over the next 6-8 weeks they will. Now is the time to examine and repair torn screens, faulty caulking, and any gaps around windows, doors and siding to prevent their entrance when they do attempt to become a household nuisance.
Report by Robert Childs, Entomologist - Retired, UMass Extension, Amherst
Diseases
Recent pathogens and insect pests of interest seen in the UMass Extension Plant Diagnostic Laboratory:
Leaf and fruit spot, caused by Entomosporium mespili, on bosc pear (Pyrus communis). These orchard trees are approximately 10-years-old and were planted four years ago. Symptoms were not present in previous years, although scab and rust diseases were present. Numerous dark-colored, circular spots were present on the leaves and fruit. The spots often coalesce over the growing season to create large, necrotic blotches. Trees can be nearly defoliated by early September and the fruit becomes spotted and often splits open, rendering it unsalable.
Shoot blight, caused by Phomopsis and Botryosphaeria, on blue spruce (Picea pungens). Two trees, both 12-years-old and present at the site for 10 years, with varying symptoms. On the first tree, the current season's needles in the upper canopy became pale green to brown earlier this summer. The shoots were infected with Phomopsis and there were no symptoms of signs of needle cast present. The second tree was experiencing browning of this year's growth on the lower canopy branches. The shoots on this tree were infected by Botryosphaeria and again, there were no symptoms or signs of needle cast. Both of these fungi can be regularly found on declining blue spruce, attacking small twigs and stems but are not considered primary pathogens on healthy trees.
Boxwood leafminer (Monarthropalpus flavus) infestation on common boxwood (Buxus sempervirens). Pale green to yellow, circular, raised spots were observed on the underside of this year's foliage. When the leaves were cut open, numerous green and very small larvae of the boxwood leafminer were present. This insect overwinters inside the leaves and in the spring, the leaves become swollen and distorted as the larvae mature before they emerge. The shrubs were installed in late May to early June on the property and their age is unknown.
Spruce spider mite (Oligonychus unuguis) and elongate hemlock scale (Fiorinia externa) infestation, needle cast caused by Rhizospharea and stem cankering caused by Seiridium abietinum on Fraser fir (Abies fraseri). Nine trees planted 18 years ago as a screen along a property border. Over the past five years, two trees developed browning needles and branch dieback; one is now dead. Underlying/predisposing stresses may be initiating the dieback, leading increased susceptibility to insect and disease attack.
Diplodia shoot and needle blight, caused by Diplodia pinea, on blue Atlas cedar (Cedrus atlantica). Tree is less than 20-years-old and has been present at the site for 12 years. In the past eight weeks, needles are prematurely shedding throughout the entire canopy. Symptoms were not observed in previous years. A secondary needle blight caused by Pestalotiopsis and Phomopsis was also detected. While not a common host for Diplodia, the damage inflicted on Atlas cedar is just as severe as on hard pines.
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: http://extension.umass.edu/landscape/diseaseguide
Report by Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass, Amherst.
Weeds
At this point in the season, summer annual weeds have become large. Many weeds have become very large and just spraying them will result in unsightly dead vegetation, so hand weeding may be necessary. However, spot spraying with a non-selective herbicide is usually a better strategy than hand-weeding because it does not break the mulch barrier. A determination on a site-by-site basis will need to be made.
Inspect areas of the landscape where new trees or shrubs, especially those that were field grown, were planted early this season or last year. Look for perennial weeds that may be growing from the root ball. Canada thistle, mugwort, quackgrass, bindweed and horsenettle are some of the possible culprits.
Japanese knotweed is in flower and now is the time to manage this invasive plant. Use a 2% spray solution of glyphosate sprayed to the initiation of spray drip. Do not use herbicide formulations that contain diquat (RewardTM) or tank-mix pelargonic acid (ScytheTM) with the glyphosate. Diquat and pelagonic acid are contact herbicides and have the potential to decrease the efficacy of glyphosate. In areas near water, a formulation of glyphosate that is labeled for these areas should be used. Non-chemical products containing clove oil, citric acid, acetic acid or orange extract will not effectively control Japanese knotweed.
Poison ivy can be treated during the month of September. Glyphosate or triclopyr are the best herbicides for poison ivy control. Contact (ScytheTM, RewardTM) or the non-chemical/organic herbicide products will provide "burndown" activity only and will not adequately control poison ivy.
The 2014 weed season continues to be an interesting one. While some of our normal weed issues were very problematic others were not anywhere near the troublesome levels that we normally see. These challenges or lack thereof are strongly location and site dependent. However tempting it may be, now is not the time to look for excuses for insufficient weed control. Now is the time to examine your weed programs and look for the reasons for poor or lacking weed control. Examine each site and the weed management practices employed and see if you can identify a weak link or two.
Report by Randall Prostak, Weed Specialist, UMass Extension Agriculture & Landscape Program, Amherst.
Be sure to check out UMass Extension's Online Weed Herbarium!
Name that weed! (Click photo to enlarge, and click here for answer)
Landscape Turf
Management Practices
Renovate or Reconstruct?
When turf performance deteriorates below an acceptable level and cannot be improved through normal cultural practices, re-planting might be the next logical step. At this point in the season we are within the ideal period for turf establishment projects. In the case of existing turf areas, there are two basic approaches to re-establishing the turf on a site:
Renovation (less disruptive) – Process of replacing the turf plants on a site without making changes to the soil or grade. Does not normally include total removal of existing turf, but usually includes eradication of the existing stand with non-selective herbicides or extended covering. May include some superficial cultivation in the interest of promoting seed-to-soil contact.
Reconstruction (more disruptive) – Involves wholesale removal of existing turf on a site in conjunction with tilling or other soil cultivation, at least to the depth of the root zone or deeper. Frequently also includes addition of soil amendments, addition of topsoil, and/or changes to grade.
In straightforward terms, if renovation compares to remodeling an out-of-date kitchen, reconstruction is like rebuilding the whole house (see figure below). Renovation is most appropriate when turf has deteriorated due to stress, pest damage or unadapted grasses, but the soil and overall growing environment remain generally suitable. A general guideline is to renovate when 50% or more of the turf is composed of undesirable grasses or weeds. Renovation is a great opportunity to more closely match grass species and varieties to site conditions.
When there are ongoing problems that go beyond just the plants present, a full-scale reconstruction may be warranted. A decision to take on a reconstruction project should be carefully considered; as in is it necessary to start from scratch? In modern medicine, for example, there is an effort to better tailor patient treatments to precisely fit the severity of the condition. When health problems are dire or life threatening, there is more opportunity to gain from major intervention. When issues are less severe, however, major intervention may be less appropriate because there is smaller opportunity for benefit. In other words, the risk of net harm is increased when the degree of intervention is greater than what the problem truly requires.
Decisions to 'open' the soil in a turf system, as is the case with reconstruction projects, should always be approached cautiously. Cultivation can damage soil structure, introduce the possibility of soil erosion, and stir the 'seed bank'. At the same time, cultivating the soil provides opportunities not typically available in a perennial turf system including ability to incorporate fertilizer and soil amendments, improve drainage, and alter the grade. In other instances, digging may be required to remove boulders or buried debris, or to install physical infrastructure such as irrigation system components. Therefore, in the majority of circumstances complete reconstruction should be based on identifiable need or, from a strictly agronomic perspective, treated as a last resort.
Compared with renovation, reconstruction is more expensive, time-consuming, labor intensive, and functionally and aesthetically disruptive. When circumstances or budget do not permit a justifiable reconstruction, a renovation approach will most often yield measurable improvement. Even in situations where the means and need for reconstruction exist, opting for renovation first may at best have satisfactory results and at least buy some time (perhaps multiple seasons) before the larger investment of funds and energy in a wholesale reconstruction project.
While we're on the subject of establishment, don't forget the additional option of seeding into an existing, living stand. Late summer is a perfect time for overseeding, which often involves seeding into established turf in the interest of repairs or maintaining adequate density. Other times the goal is to gradually introduce different grass species or cultivars and alter the stand composition over time; this process is sometimes referred to as interseeding.
Report by Jason Lanier, Extension Educator, UMass Extension Agriculture & Landscape Program
Other Relevant News / Pest Alerts
UMass Soil & Plant Tissue Testing Lab Moving: The move will take place on Monday, September 16. Please be aware that turnaround time may be delayed by this transition, and thank you in advance for your patience and understanding. The new address for samples will be:
UMass Soil and Plant Tissue Testing Lab
203 Paige Laboratory
161 Holdsworth Way
Amherst, MA 01003
The UMass Soil and Plant Tissue Testing Laboratory is open Monday through Friday from 8:00 AM to 4:00 PM. As always, if you need to contact the lab call 413-545-2311, e-mail soiltest@umass.edu, or visit http://www.umass.edu/soiltest.
UMass Extension's 2014 Green School is a comprehensive 12-day certificate short course for Green Industry professionals taught by UMass faculty and Extension Specialists. Three different track options are offered: Turf Management, Landscape Management and Arboriculture. Offering 60 hours of training, this popular course is designed for professionals who wish to gain a basic understanding of horticulture fundamentals and strategies, but who can't fit a full academic course into their schedules. For complete program information and registration instructions, refer to our Green School page.
2015 Winter School for Turf Managers: An excellent choice for turf professionals who seek to expand their knowledge and practical skills. Students are immersed in an intensive, full-time program scheduled Monday through Friday for seven weeks. For complete program information and application instructions, refer to our Winter School page.
