Aug 1, 2017A monthly e-newsletter from UMass Extension, published March to October, for home gardeners. To read the articles in each section of the newsletter, click on the section headings below to expand the content: Tips of the Month August is the Month to….. Damage to trees by gypsy moth caterpillars was sporadic this year, with some areas seeing massive defoliation and others seeing very little. Even within neighborhoods, some trees were defoliated while others were barely damaged. However, those trees that were defoliated need to put out a second flush of foliage to thrive and survive. Water is critical for this, so those trees and shrubs will need to receive at least one inch of water over the root zone, once or twice a week in hot, dry weather from now until they go dormant in late fall. For a mid-fall crop, sow seeds at the beginning of August of beets, dill, radish, kale, Swiss chard, carrot, fennel, lettuce, arugula, and escarole. Transplant seedlings into the garden of broccoli, cabbage, Chinese cabbage, cauliflower, Brussels sprouts and kohlrabi. At the end of the month, sow seeds of spinach for a crop in October. Wormy apples are usually the result of egg-laying in developing apples by the apple maggot fly. Continue to manage apple maggot flies according to directions on the pesticide label. Order garlic now for planting in mid-October for a harvest next year. Try to order garlic varieties that grow will well in New England. Wait until September to fertilize lawns. It pays to grow plants at the proper soil pH. Soils growing vegetables, lawns, flowers, etc. can usually benefit from an application of limestone: ag.umass.edu/turf/fact-sheets/soil-ph-liming The UMass Soil Testing Lab at UMass Amherst tests soils for pH and nutrient needs. Now is a good time to have your vegetable garden soil or lawn soil tested. More info on fees and how to take a sample can be found at ag.umass.edu/services/soil-plant-nutrient-testing-laboratory/ordering-information-forms August into early September is a terrific time to renovate (dethatch, core aerate, overseed, etc.) an existing lawn or to construct a new lawn. Select and purchase a high quality grass seed mixture specific for the area (sun, shade, play area, etc.) to be seeded. Check out endophyte-infected, improved cultivars of tall fescue, perennial ryegrass, and fine fescues which are more drought-tolerant and resistant to foliar-feeding insects (chinchbugs, sod webworms, billbugs). ag.umass.edu/turf/fact-sheets/endophyte-enhanced-grasses Order spring flowering bulbs (crocus, daffodil, tulip, snowdrops, glory-of-the-snow, grape hyacinth, etc.) for fall planting. Late August into September is a good time to divide or transplant spring-flowering herbaceous perennials like bearded iris, Siberian Iris, peonies etc. It is also a good time to divide or transplant daylilies and hosta. Don’t forget to water the plants after transplanting and/or dividing and continue to do so until the plants go dormant. Try to eliminate weeds before they go to seed. Continue to weed vegetable gardens, borders, etc. and don’t let those weeds go to seed. Once weeded, considering applying a 2-3 inch layer of mulch over the soil. Continue to water, fertilize, and trim back annuals and tropical plants in containers and in the garden. These plants will usually continue to flourish up until frost and will provide color in the landscape. Also, before a deep frost or freeze kills them, consider, or make plans, to overwinter plants like dahlia, canna, geranium, Colocasia, banana, etc. that can be brought indoors and saved for garden use next year. pss.uvm.edu/ppp/articles/tender If your tomatoes are being eaten and the plants stripped of leaves, check for a green caterpillar called the tomato hornworm (often easier to see at night). Another sign that these caterpillar pests are present is that you will see greenish-black droppings (caterpillar ‘frass’ or excrement) on the foliage. Handpick and destroy tomato hornworm caterpillars when found. Be on the lookout for baldfaced hornets, yellow jackets and other wasps at this time of year, as their colonies are getting larger. Nests may be found in the soil, in old railroad ties, old tree stumps and stone walls, etc. Be careful when pruning shrubs and trees as bald faced hornets often build basketball or football sized grey-papery nests in trees or shrubs. Yellow jackets, baldfaced hornets and other wasps can sting multiple times. Many wasps are attracted to meats and sweet beverages at outdoor gatherings; take precautions. Mosquitoes have been very active in many areas this year. Some are carrying diseases like West Nile Virus. Continue to drain any containers that retain water (plants saucers, old tires, plant pots, etc.) as they are a possible breeding ground for mosquitoes. Change and clean out the water in bird baths frequently and also consider using Bti (Bacillus thuringiensis israelensis), a biological control, in standing water to manage mosquito larvae. Bti can also be used in plant saucers, etc. Continue to take precautions against ticks and mosquitoes. While mosquitoes die after a cold freeze in the fall, deer ticks may be active almost any time the weather is above freezing. www.mass.gov/eohhs/gov/departments/dph/programs/id/epidemiology/ticks/public-health-cdc-tickborne-overview.htmlwww.mass.gov/eohhs/gov/departments/dph/programs/id/epidemiology/providers/mosquitoes-and-ticks.html Take a walk around your property and look for dead or dying trees or tree branches that may cause damage to people or property if they should come down in a storm. Contacting an insured, Massachusetts Certified Arborist for a consult and possible pruning and/or tree removal, before hurricane season and before winter storms arrive, may alleviate unnecessary future anxiety and property damage. Deborah C. Swanson, Horticulturist Timely Topics Late Blight of Tomato Detected in Massachusetts Late Blight of tomato has been detected in Massachusetts for the first time this growing season. This disease is caused by the fungus-like organism Phytophthora infestans and can affect both tomatoes and potatoes. It should not be confused with Phytophthora blight (caused by P. capsici), which affects squash as well as tomatoes and peppers, or two other common leaf blights of tomato, Septoria Leaf Spot (Septoria lycopersici) and Early Blight (Alternaria solani) - more details about managing both of these at ag.umass.edu/vegetable/fact-sheets/tomato-leaf-blights. Late blight has also been reported to affect petunias and nightshades. Symptoms of late blight include dark, water-soaked lesions on leaves, often with fuzzy white sporulation on the underside. Lesions can also occur on stems. Sporangia (asexually produced spores) are dispersed by splashing water or by wind. Under optimum conditions, three to four days may elapse between infection and the appearance of symptoms. Infected plants should be removed and disposed of. Do not compost infected material. Volunteer potato plants should be removed from gardens when they emerge in spring, as the pathogen may survive the winter in infected tubers. Control solanaceous weeds such as nightshade and henbane. Fungicides may be used to protect remaining healthy plants from infection. Keep in mind that infected plants should still be removed when possible and that plants may be infected but not yet showing symptoms. Fungicides will not make existing infections disappear, but can protect uninfected plants from becoming infected. For more information, go to the UMass fact sheet on late blight at ag.umass.edu/vegetable/fact-sheets/solanaceous-late-blight. For information about fungicide options, see the New England Vegetable Management Guide (nevegetable.org) It is always best to start with disease-free plants. Purchase certified seed potatoes; do not save seed from infected crops or plant tubers purchased in grocery stores. Start tomatoes from seed (P. infestans does not infect tomato seed) or buy seedlings that have been produced locally. Keep vegetables and ornamentals well separated in the greenhouse. Grow resistant or tolerant varieties; these include tomato cultivars ‘Iron Lady’, ‘Mountain Merit’, ‘Mountain Magic’, ‘Defiant PHR’, ‘Legend’, and ‘Matt’s Wild Cherry’, among others. Go to vegetablemdonline.ppath.cornell.edu for more information on resistant and tolerant varieties. Farmers, greenhouse growers, and home gardeners should have possible late blight infections positively identified by Extension personnel. Please see ag.umass.edu/services/plant-diagnostics-laboratory for information about submitting samples. Dr. Angela Madeiras, UMass Extension Plant Diagnostic Lab News for Gardeners UMass Garden Calendar Photo Contest We're having a photo contest for the 2019 UMass Extension Garden Calendar, so have your camera handy and keep an eye out this summer for contest-worthy pics! The deadline for submitting pictures is April 1, 2018. Submission details are at https://ag.umass.edu/landscape/publications-resources/garden-calendar/garden-calendar-photo-contest. August Lawn Care Philosophy Here in New England, typical priorities during the month of August are vacations and relaxation, and that mindset happens to mesh very well with the ebb and flow of seasonal lawn care practices. As far as lawns are concerned, August is a month for easing off the throttle and occasionally tending to the basics. July and August are typically the most stressful months for our cool season grasses due to hot and dry conditions, leaving many lawns a little worse for wear by late summer. Here’s a checklist of do’s and don’ts for August: DO keep mowing according to the 1/3 rule (remove no more than 1/3 of the grass height at a time), as long as the grass is growing and not dormant. If prevention of dormancy is desired, DO irrigate deeply at the first signs of moisture stress if natural rainfall is not sufficient. DO keep an eye out for problem areas such as disease infection or chinchbug damage. DON’T apply pesticides. August is not an appropriate time for many herbicide and insecticide applications. Definitely DON’T apply herbicides on days when temperatures are forecast to exceed 85° F. DON’T fertilize. In most lawn settings, August is not an appropriate time for fertilizer applications. The key now is to not undertake practices that will push growth or introduce more stress into the equation during an already stressful time. Instead, rest up and conserve energy for prime time, which is right around the corner. As the calendar turns to September, temperatures normally moderate and rainfall increases, creating a sizeable period of favorable conditions for grass growth. This makes the first part of September a crucial time of year for lawn maintenance in this region. An investment of time and resources will help to ensure quick recovery from the rigors of summer and pay big dividends going forward. Fertilize: Early September is the most important time to fertilize lawns in New England. Adequate nutrient availability along with the excellent growing conditions characteristic of late summer and early fall promote re-growth of root systems that have died back due to heat, as well as increased tillering and lateral stem production that increase turf density. Even for very low maintenance sites where there is only one fertilizer application per year, the first part of September (approximately Labor Day) is the time to do it. Plant: Late summer is also the best time for turf establishment, which includes planting of new lawns, renovation, overseeding, and repairs. Planting during this time aligns the delicate establishment period for new plants with the best possible conditions for success; there will be another favorable period in the spring before their first encounter with summer stress. In early September, soils are typically warmer, which aids germination, and drier, so they’re easier to prepare. In late summer, there is very little if any competition from germinating annual weeds for new seedlings, which can be a monumental problem when planting in the spring. Cultivate: September is an ideal time for cultivation practices like dethatching and aeration. Though these practices have a net benefit, temporary injury to plants (bruising, crushing) as well as disruption to appearance and function of the turf often occur. Aligning these practices with good late summer growing conditions helps to ensure that the plants will be under as little stress as possible, making recovery rapid and complete. Some form of cultivation is often performed in conjunction with planting or overseeding; practices like aeration help fertilizers and liming materials to "access" the root zone, and cultivation is much less likely to stimulate weed growth later in the season compared to spring, making cultivation even more sensible and appropriate during late summer. Lime: Although lime can be applied any time that the soil isn’t frozen, September is a great time to assess soil pH with a soil test (http://ag.umass.edu/services/soil-plant-nutrient-testing-laboratory) and lime if necessary. The UMass Soil Testing Lab is not nearly as busy as during the spring rush, which means a quicker turnaround time for samples. Since lime needs months to react and neutralize acidity in the soil, an increasing benefit will be realized throughout the fall and you’ll be in great shape for next season. So… take it easy in terms of the lawn this month. If you simply must do something lawn-related in August, get your supplies, gear up, and get ready for September. With a few straightforward projects, you can get ahead of the game for spring and the start of next season. With good timing and good weather, the lawn will improve week by week and make a great back drop against changing foliage later in the fall. Jason D. Lanier, UMass Extension Turf Specialist Trouble Maker of the Month Dutch Elm Disease Dutch elm disease (DED), caused by the fungal pathogen Ophiostoma novo-ulmi, has been rampant on both young and mature American elms in 2017. In several cases, mature trees that have resisted the disease for many years have succumbed and died, even those receiving regular fungicide injections to control the fungus. Drought conditions that developed in 2015 and persisted throughout 2016 predisposed many American elms to the disease. Symptoms of DED typically first appear in the upper canopy as yellowing of leaves on outer shoots (a symptom known as flagging). If left untreated, premature leaf shedding and canopy dieback ensues. The fungus then spreads systemically throughout the tree within the vascular tissue. As the vascular tissue is killed, the tree is unable to move a sufficient volume of water from the roots to the canopy and the tree dies. American elms represent some of the most culturally and economically significant urban, suburban and rural trees. Their contributions to the landscape are numerous and include: carbon sequestration, capture of storm water and airborne pollution, reduced cooling costs from shade and enhanced aesthetics and property values with their large, vase-like canopies. Prior to the introduction of DED, American elms dominated the urban and suburban landscape because of their beauty, rapid growth rates and ability to thrive in difficult growing conditions. Despite the devastating effects of the disease, thousands of American elms still occupy the urban and suburban landscape today. Considering the devastating impacts of DED, it’s appropriate to ask: Is it worth planting American elms knowing they will likely be challenged with Dutch elm disease at some point in their life? The answer is a resounding yes! Several cultivated varieties (cultivars) of American elm have been developed that demonstrate a high resistance to DED. These are true American elms and not hybrids of American elm that have been crossed with Asian or European elms. The most widely available American elm cultivars at New England nurseries are 'Princeton' (U. americana ′Princeton′) and 'Valley Forge' (U. americana ′Valley Forge′). While both cultivars offer good to excellent resistance to DED, they have their detractors. The Princeton cultivar typically has a compact canopy that is uncharacteristic of American elm and with age, weak branch unions can lead to breakage under snow or high winds. The Valley Forge cultivar develops a more broadly spreading canopy typical of American elm, but frequently requires regular pruning at an early age to properly shape the canopy. Due to poor canopy structure and rapid growth rates, Valley Forge elms are subject to branch failure, especially in windy, exposed settings. But with intervention, both can develop structurally sound canopies. Additional cultivars that are not as widely available include 'Jefferson' (U. americana ′Jefferson′), 'New Harmony' (U. americana ′New Harmony′) and 'Prairie Expedition' (U. americana ′Lewis & Clark′). Of these, the Jefferson cultivar offers dark green foliage, a broadly-spreading canopy that is typical of American elm and good canopy structure. This cultivar is not as widely available because the parent tree, which resides at the National Mall in Washington D.C., is sterile and cultivars must be propagated from stem cuttings. However, with a little effort, it can be found at New England nurseries in sizes ranging from small saplings to young trees. A recent published study demonstrated that Valley Forge and Prairie Expedition American elms offer the highest level of resistance to DED, in comparison to New Harmony and Princeton elms. Both Valley Forge and Prairie Expedition cultivars were found to better restrict growth of the pathogen within infected vascular tissue once the infection established. It is important to understand that resistance to DED does not mean immunity. Resistance means an elm can be infected with DED but, if otherwise healthy, has the ability to restrict and compartmentalize the growth and spread of the pathogen. Immunity, in contrast, means that a particular tree or shrub cannot become infected by a specific plant pathogen. Sugar maple is immune to DED, as Ophiostoma novo-ulmi cannot infect maples. Maintaining high vigor of American elm cultivars is also important to ensure they have the resources to withstand DED. Establishing a large mulch ring around newly planted trees ensures they will not be injured by string trimmers or have to compete with turf grasses for water as the root system establishes. Regular watering when trees are newly planted limits the shock of transplant and helps the tree establish more quickly at the site. Americans elms can adapt to a range of sites, but are most naturally abundant in floodplain forests where soil moisture is plentiful. Limiting feeding damage by various insect pests, such as gypsy moth and Japanese beetles, can ensure trees have the foliage they require to maintain a robust defense response. With proper care after transplanting, most American elms can become thriving members of the landscape, better able to resist infection by, what is now unfortunately, a naturalized fungal pathogen in North America. Dutch elm disease isn’t going away, but planting American elms should not be avoided for this reason. Instead, they should be planted because of DED, to help restore the American elm population in the landscape. Nick Brazee, UMass Extension Plant Pathologist Plant of the Month Echinacea purpurea, Purple Coneflower Echinacea purpurea, commonly known as Purple coneflower, is a long flowering perennial native to eastern North America and hardy to USDA hardiness zones 4-9. It is a medium sized herbaceous perennial with an upright, clump growth habit growing 2-3 feet tall and 18-24 inches wide. In optimal conditions, it can grow up to 5 feet with a 2 foot spread. Purple coneflower prefers a well-drained soil in full sun or partial shade. Plants are tolerant to heat and drought once established. The leaves of Echinacea purpurea are medium to dark green, and originate as a clump from the crown (basal leaves) or alternating along the flowering stems (upper leaves). Leaves tend to wilt under drought conditions but recover with the evening dew and reduced transpiration. Echinacea offers a distinctive array of daisy-like flowers in many colors including purple, pink, white, orange, yellow, and green. The best floral performance occurs when Echinacea is planted in sites with morning sun followed by afternoon shade. Echinacea blooms from June to August with re-blooming occurring in late summer and early fall. Deadheading encourages re-bloom and improves general appearance. The flowers are attractive to butterflies and bees. Echinacea is suitable for mass plantings, as a perennial border, or in entryways. It is also good for cut flowers. Echinacea purpurea is easy to grow and is not a heavy feeder. Avoid heavy fertilization, which leads to tall, leggy plants that fall over. Plants can be propagated by clump division, root cuttings from peripheral roots, or by seeds. Divide clumps about every 4 years when they become crowded. Echinacea can self-seed, especially if some of the seed heads are left in place. This can slowly become a problem in perennial beds. Leaf scorch is the most common problem and often occurs during drought periods. Other problems of Echinacea include aster yellows disease, leaf spot disease, and Japanese beetle. Some of the popular varieties include: Echinacea ‘Crimson Star’- deeply pigmented crimson-lavender petals with reddish central disks Echinacea ‘Magnus’ – rosy purple flowers Echinacea ‘White Swan’ - White petals with golden-green central disks. Echinacea ‘Firebird’ – Red-orange flowers, long lasting flower color Echinacea ‘Glowing Dream’ – Deep watermelon pink flowers, purple stems. Flowers glow. Echinacea ‘Balsomador’ – Bright deep orange flowers Echinacea ‘Millkshake’ – Double creamy white flowers Geoffrey Njue, UMass Extension Floriculture Program Additional Resources Landscape Message - for detailed timely reports on growing conditions and pest activity Home Lawn and Garden Resources Find us on Facebook! www.facebook.com/UMassExtLandscape/ Follow us on Twitter for daily gardening tips and sunrise/sunset times. twitter.com/UMassGardenClip Diagnostic Services The UMass Extension Plant Diagnostic Lab provides, for a fee, 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. Sampling procedures, detailed submission instructions and a list of fees. The UMass Soil and Plant Nutrient Testing Laboratory at the University of Massachusetts Amherst provides test results and recommendations that lead to the wise and economical use of soils and soil amendments. The Routine Soil Analysis fits the needs of most home gardeners. Sampling procedures plus the different tests offered and a list of fees. Spread the Word! Share this newsletter with a friend! New readers can subscribe to our Home Gardener E-Mail List.