Back to top

Garden Clippings 2017 Vol. 36:3

May 1

A 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

May is the Month to…..

•    Plant flower and vegetable transplants.  While gardeners anxiously await the typical last frost date in order to set out tender species, there is more to think about than whether or not your prized crops will get nipped by a cold night.  Another key consideration for the annual vegetable garden is rotation; as in what gets planted where.  Rotation is an important practice that helps prevent unwanted pests and diseases from accumulating to devastating levels.  Basic rotation involves not planting a species from the same family in the same location more than once every three years.  The most common vegetable garden families include Solonaceous plants (tomatoes, peppers, potatoes), Cucurbits (squash, cucumbers, melons), Brassicas (broccoli, cabbage, cauliflower, kale), and Legumes (beans, peas).

•    Fertilize the lawn, especially if there has not been a fertilizer application yet this season.  Nutrient availability is best coordinated with periods of vigorous growth, making the importance of spring fertility second only to late summer in New England.  Fertilizers should have a higher percentage of slow release nitrogen later in the spring, and applications should be avoided altogether once the heat and drought stresses of summer set in.  Fertilizers should only contain phosphorus if a deficiency has been demonstrated by a soil test, or if being applied in conjunction with seeding or overseeding, according to Massachusetts nutrient management regulations. For info on how to get a soil test, go to soiltest.umass.edu.

•    Begin thinking about white grubs.  In this region, the most common approach for dealing with grubs is a preventive, or “season-long”, type application.  If grub damage or related foraging is present in the fall or spring, a preventive material will not control the mature populations present at those times.  Instead, the objective is to have the material in place when the next generation of grubs hatches in late-July and August.  Preventive products that contain chlorantraniliprole (AceleprynTM) as the active ingredient take 60 to 90 days to fully activate in the soil, so are therefore best applied during the month of May.  Other commonly available preventive materials (eg. imidacloprid [note: DyloxTM is not a preventive material]) take much less time to activate and are best applied in July.  Any grub treatment should always be watered-in according to label directions. 

•    Ensure that mower blades are sharpened up for the season.  Did you know that grasses ‘mow’ differently depending on species?  Grasses with more lignified shoot tissues, such as ryegrasses, do not mow as cleanly by nature compared to grasses that have less lignin in their leaf blades, such as bluegrasses… meaning that the effects of a dull mower blade will be magnified with certain species.  It isn’t all about appearance, however.  The jagged, tearing cut of a dull blade can actually increase water use significantly when considered on the scale of an entire property, leading to more stress on the lawn, the pocketbook, and increasingly scarce water resources.

•    Scout Japanese andromeda, azaleas, rhododendrons and hawthorns for lacebug infestation.  Lacebug damage typically occurs as yellow stippling of the foliage and numerous brown spots (lacebug excrement) on leaf undersides.  While this injury is not immediately threatening, plant aesthetics can be significantly impacted and plant vigor can be measurably reduced over time.  Plants on sunny sites are more susceptible to lacebugs.  The insect overwinters as eggs embedded on the undersides of the foliage, and hatch normally begins in late May.  After hatch, a carefully applied horticultural oil or insecticidal soap spray directed at leaf undersides can be very effective at reducing populations below damaging levels.

•    Get serious about tick bite prevention.  May is the month that folks return to the landscape in earnest, greatly increasing the probability of crossing paths with ticks that can transmit serious infections such as Lyme disease or anaplasmosis.  Steps such as avoiding tick habitat, showering after outdoor activities, and daily tick checks are crucial, but one of the best ways to protect yourself is through the appropriate use of repellents. The most effective current repellent approach involves the active ingredient permethrin, which is used to treat clothing and footwear, and the effectiveness typically lasts through multiple washings.  Sprays and kits are available to treat clothing at home, pre-treated clothing is available, and services exist that provide ‘to order’ treatment of clothing items as well. 

•    Prune spring flowering shrubs… AFTER flowering.  While late winter is the traditional pruning time for many tree species, the same approach is not appropriate for some of our most treasured spring bloomers.  For shrubs that bloom on ‘old wood’ (i.e. last year’s growth), pruning in late winter translates to removing buds that would otherwise bloom shortly thereafter.  Instead, the correct practice is to prune these species as soon as possible after bloom concludes, leaving ample time for new growth in the current season and helping to ensure an impressive bloom in the following season.  Examples of species that benefit from pruning after flowering include viburnums, azaleas, rhododendrons, lilacs, Pieris spp., and Weigela spp.

•    Do NOT remove foliage of spring flowering bulbs… until withering occurs.  Along similar lines as the previous tip, it is imperative to leave the foliage of spring flowering bulbs intact after flowers fade.  While it is tempting to remove foliage to keep things tidy or to make way for new plant material, the foliage continues to photosynthesize.  This activity produces the sugars that will be stored to enable emergence and flowering the following spring; therefore, removing foliage could jeopardize the bulb.  To further pamper your bulbs, make a high phosphorus fertilizer application (bonemeal is a good source) when flowering ends.

•    Get a jump start on weeding.  May is a great month to spend some time pulling garden and landscape weeds, as infestations have not yet become overwhelming.  Every weed removed now that doesn’t go to seed is an investment in fewer weeds in the current and future seasons.  Weeds are easiest to remove when the soil is moist.  Many annual weeds are shallow-rooted, and pull relatively easily. They can also be smothered with mulch at this time of year.  Spend a little more time on perennial weeds – all of the underground portions of the plant must be removed or the plant is likely to sprout again.

•    Set up hummingbird feeders for the season!  Hummingbirds return to Massachusetts from their southern migration by late April/early May in most years, so the best time to have feeders ready is by the first week of May.  According to the Massachusetts Audubon Society, feeders should be cleaned and re-filled at least once a week to prevent mold growth.  Also, if ants invade your feeder, don’t sweat it… hummingbirds actually eat both nectar and insects.

Jason D. Lanier, UMass Extension Specialist

Timely Topics

Using Cultural Practices and Non-Chemical Weed Control in the Landscape and Garden

Spring has arrived in New England and brown slowly turning to green marks the start of another gardening season when gardeners experience renewed enthusiasm for their ornamental landscapes, lawns and vegetable gardens. Whether it is new gardening endeavors or projects from last season that did not work out as favorably as one would have liked, now is the time to look forward to a fresh start. 

One of the things gardeners are not looking forward to is another season of battling with the unwanted plants known as weeds. In recent years, an increasing number of gardeners have sought weed control solutions that do not rely on the use of chemical weed control products. 

Recently, a variety of non-chemical weed control products have been made available in garden and home centers. Unfortunately, many of these products will not provide the desired level of weed control. The only group of products that may provide some effective weed control are the “contact”, non-selective products which contain the active ingredients acetic acid, clove oil, citric acid, or potassium salts of a fatty acid. Available products that contain these active ingredients, either individually or in combinations, can be used to control young summer and winter annual weeds or seedlings of perennial weeds. “Contact” products only kill or injure the parts of the plant that are sprayed; consequently, they will not control established perennial weeds, which are able to regrow from their roots. Since these non-chemical weed control products are somewhat limited in their performance, other strategies need to be used that might suppress or reduce weeds in landscapes, lawns and gardens. Here our focus shifts to the use of cultural practices. If you wish to control weeds without using chemical weed control products, begin with the cultural practices and/or strategies suggested below.

Ornamental landscape beds
Landscape mulches are the first and best defense against weeds in landscape beds. Compost should not be used as a landscape mulch, since it provides the perfect medium for growing weeds and may contain weed seeds if it was not sufficiently heated during the composting process. Summer and winter annual as well as perennial weed seedlings can be spot sprayed with one of the non-selective, non-chemical, “contact” weed control products mentioned above to kill the upper portion of the seedling. While these products will not kill landscape tree, shrubs or perennials, overspray to plant foliage nearby should be avoided as temporary injury can occur.

Lawns
The old adage “Weeds are the result of a poor lawn, not the cause of a poor lawn” leads us in the right direction when attempting in reduce weeds. In other words, a neglected lawn came first and the weeds, having less stringent requirements for growth, followed. Lawns that are healthy and dense have an inherent, competitive advantage against weeds. We encourage lawn grasses to be competitive with the use of cultural practices just as we promote human health with a good diet, exercise, and sufficient sleep. Similarly, lawn grass health is promoted by cultural practices such adequate fertility, soil acidity correction, mowing, irrigation and alleviation of soil compaction.

Vegetable gardens
The key component of weed management in vegetable gardens includes light hoeing or cultivation before the weeds appear or when the weeds are very, very small. Large weeds can be hand-pulled. Mulch materials can also have great value. Straw or saltmarsh hay are good choices, since neither are likely to contain weed seeds. Mulch hay, which often contains many seeds of grasses that become weedy in the garden, and landscape mulches, which are slow to break down and so tie up needed nitrogen, are not recommended and should be avoided.

If, after time, you are not achieving sufficient weed control using non-chemical weed control products and the appropriate cultural practices outlined above, the use of chemical weed control products may be another option. As with both chemical and non-chemical weed control products, gardeners need to read, understand and follow the product directions. This is important not only for safety, but also to achieve the best results a product can offer.

Randy Prostak, UMass Extension Weed Specialist

News for Gardeners

Massachuetts Pollinator Protection Plan

The Massachusetts Department of Agricultural Resources has developed a Massachusetts Pollinator Protection Plan. It is a set of voluntary guidelines that discuss best management practices for stakeholders seeking to promote the health of the European honey bee and other pollinators. This document includes information for beekeepers, pesticide applicators, land managers and farmers, nurseries and landscapers, and homeowners and gardeners. For more information, go to www.mass.gov/eea/docs/agr/farmproducts/apiary/pollinator-plan.pdf .


Lily Leaf Beetle Project

The University of Rhode Island Biological Control Lab is researching ways to find a natural method to combat lily leaf beetle. Small parasitic insects have been established in lily plots in Cumberland, RI and Wellesley, MA in hopes that these insects will disperse naturally to reduce the effects of the lily leaf beetle.

In an attempt to track these parasitic insects, URI would like to collect the larvae found on your lilies (they can be identified as the brown blobs, since they cover themselves in their excrement). The larvae will be dissected to identify the parasitic insects.

If you have larvae in your (or customers) yard, please send to URI, following the instructions on the URI Biocontrol Lab website.


Corrective Measures and Management of Over-Fertilized Soils

Soils in New England are naturally low in essential nutrients needed for crop production due to high yearly rainfall that leaches out many nutrients. Phosphorus is the only nutrient element that is usually adequate in New England soils because it is not susceptible to leaching. Most soil phosphorus is tightly bound to the soil particles. The exception is in soils with very high phosphorus in close proximity to water.  In these cases, phosphorus may be leached into waterways, causing algae blooms and killing fish.

There are several reasons why your soil might have high nutrient values. It may be caused by over-fertilization, or the overuse of compost, manure or other organic materials. It has become increasingly common for soils from gardens and small farms processed by the UMass Soil and Plant Nutrient Testing Lab to contain excessive nutrients, high organic matter and high soluble salts. 

Soluble salts are dissolved inorganic solutes such as calcium, magnesium, sodium, chloride, sulfate, bicarbonate, potassium, ammonium, nitrate, and carbonate which are also found in most soils. Sources of soluble salts include commercial fertilizers, animal manures, soil organic matter, composts, runoff from areas where salt or ice-melt products have been used, and irrigation water that is high in dissolved salts (contaminated with road salt). 

Excessive soluble salts levels in soils can cause plants to be drought stressed because the water in the soil is pulled away from plant roots.  Soluble salts above the normal range for a prolonged period may cause root injury, leaf burn and wilting or death. 

It is important that you have your soil tested before applying fertilizer or other nutrient-supplying material such as compost in order to know the current levels of essential nutrients. The UMass Soil & Plant Nutrient Testing Lab provides testing for home gardeners; find info on fees and how to take a sample at soiltest.umass.edu

Management of soils with excessive nutrient levels

1.  Re-check your sampling method. Soil test results will only be as accurate as the sample taken. Did you follow proper sampling recommendations below? Review these guidelines and re-sample if needed.

  • Using a clean bucket and a spade, auger, or sampling tube, collect 12 or more subsamples to a depth of six to eight inches (four to six inches for turf) from random spots within the defined area. 
  • Avoid sampling garden edges and other non-representative areas.  Avoid sampling when the soil is very wet.  Avoid sampling within six to eight weeks of a lime or fertilizer application (liquid or granular).
  • Some planting media contain prills that provide controlled-release, time-released or slow release fertilizer.  These prills are small, round capsules that contain water-soluble fertilizer encased in a semi-permeable resin coating. The prills, sometimes known as Osmocote, release small amounts of nutrients when wet. They provide nutrients over time, usually for several weeks. The rate of nutrient release for most of these fertilizers is regulated by water and temperature, that is, the warmer the temperature, the faster nutrients are released. Remove prills from the soil sample prior to submittal. Prills left in a sample will result in an inaccurately high result.  
  • Break up any lumps or clods of soil, remove stones, roots, and debris, and thoroughly mix subsamples in the bucket. Submit one cup of soil from this mixture for testing.

2.  Assess plant health.  Plants vary in their tolerance to high nutrition. The first step is to assess the health of your plants.

  • If plants and roots appear healthy with green leaves, do not add fertilizer or organic amendments, including compost. Conduct a routine soil test at the end of the growing season to monitor nutrient values.
  • If plants are not healthy, do not add fertilizer or organic amendments, including compost. If you did not request a Soluble Salt test with your initial order, one may request one by contacting the UMass Soil & Plant Nutrient Testing Lab at soiltest.umass.edu.  The fee is $6 per sample when added to the Routine Soil Test.  Soluble salt levels greater than 0.6 dS/m can cause plant injury and limit growth. Plant injury due to high soluble salts depends on such factors as the stage of plant growth and weather. To improve plant growth in such soils, remove excess salts from the root zone using practices such as leaching and the use of cover crops. 

3.  Leach out salts. Leaching is the removal of soluble nutrients by applying water. To do this, water the soil thoroughly using irrigation water with low salt levels. As a general guideline for leaching out soluble salts from the top foot of soil, apply 6 inches of water to leach about 50% of the salts; apply 12 inches to leach about 80% of the salts. Note that 1” of water over 100 sq. ft. equals 62 gallons of water. For water calculations see: water.usgs.gov/edu/activity-howmuchrain.html 

4.  Cover crops. Advanced gardeners can try planting a cover crop to absorb residual nutrients left in the soil at the end of the growing season. When the cover crop is fully grown and lush, cut and remove the tops from the garden.  Compost the cut material in a different area.  In New England, plant oats, Sudangrass, buckwheat, cereal rye and annual ryegrass to absorb soil nutrients.

Plant cover crops in late summer to produce significant plant biomass before winter. This biomass captures the soil nutrients in an organic form and slowly releases nutrients when decomposing.  

Annual ryegrass and cereal rye will continue to grow and produce biomass until late November and then regrow in spring. Oats, Sudangrass, and buckwheat reach maximum biomass production when killing frost stops further plant growth. 

5.  Monitor plant nutrition. Have soil tested annually until nutrient levels drop. Do not apply fertilizer or organic amendments, including compost, until recommended by a soil test. 

Nutrient levels will come down over time through plant uptake and weathering, so waiting is sometimes the best option. If you are in New England, a high soil pH level will come down over time as well.

References: 
Cover Crops and Green Manures, UMass Extension - ag.umass.edu/fruit/ne-small-fruit-management-guide/general-information/cover-crops-green-manures 
Sundermeier A. 2010. Nutrient Management with Cover Crops. The Ohio State University Extension. Journal of the NACAA 3(1). - www.nacaa.com/journal/index.php?jid=45 
Soluble Salts in Soils and Plant Health. 2013. Cornell University Cooperative Extension and Dept. of Horticulture - gardening.cals.cornell.edu/files/2015/12/Soluble-Salts-May-6-2013-o36voh-2evtxtu.pdf 

Tina Smith, Extension Educator; Douglas Cox, Associate Professor Stockbridge School of Agriculture; Geoffrey Njue, Green Industries Specialist; and Tracy Allen, Soil and Plant Nutrient Testing Lab Supervisor. March 2017

Trouble Maker of the Month

Gypsy Moth FAQ

Q: When will gypsy moth egg masses begin hatching? What plants will they affect? 

A: Gypsy moth (Lymantria dispar) egg masses begin hatching between 90 -100 growing degree-days, using a developmental threshold of 50°F. For more information about using growing degree-days to predict insect development, go to the UMass Extension fact sheet "Growing Degree Days for Management of Insect Pests in the Landscape". Typically, this occurs around the first week in May in Massachusetts, or when serviceberry (Amelanchier) are blooming. Gypsy moth will feed on the leaves of and defoliate oak (preferred), maple, birch, poplar, willow, apple, and other deciduous plants. When their preferred hosts have been defoliated and gypsy moth populations are high, they will eat the needles of eastern white pine, spruce, and hemlock. (The 2016 population of gypsy moth did feed on conifers in certain areas.) 

Q: How long will the gypsy moth caterpillars feed?

A: Gypsy moth caterpillars, following hatch in the 1st week of May, will continue to feed and grow through roughly the 3rd week of June, at which time caterpillars typically form the cocoons within which they pupate. Following pupation, adult gypsy moth males and females will emerge around the end of June / early-July. Adult males are brown and can be seen flying to find and mate with white colored, flightless (although winged) females. The females will lay the egg masses (that they coat with the fuzzy, brownish-tan hairs from their bodies) that can contain 500-1000 eggs and will overwinter in that stage. The caterpillars are the only stage of the gypsy moth that feed. 

Q: What can I do to manage gypsy moth on ornamental plants?

A: A common management strategy for gypsy moth on valued, ornamental landscape trees and shrubs would be to apply Bacillus thuringiensis Kurstaki (Btk) on the foliage of the host plants when young gypsy moth caterpillars are actively feeding. THis is shortly after egg hatch, when caterpillars are roughly between ¼ and ¾ inch in length. Older caterpillars are not as susceptible to Btk. Btk is practically non-toxic to birds, fish, and other aquatic organisms. It is non-toxic to people and pets. Btk is also practically non-toxic to non-target insects including pollinators such as honeybees. This particular strain of Bacillus thuringiensis is toxic only to the Lepidoptera (moths and butterflies). It is a naturally occurring, soil-dwelling bacterium that must be ingested by the caterpillars to be effective. It eventually destroys their gut and causes the caterpillars to stop feeding and die. Btk products have been listed as suitable products for organic food production.

Another active ingredient, spinosad, may also be used against gypsy moth caterpillars. This is also derived from naturally occurring, soil-dwelling bacterium. Spinosad is toxic to gypsy moth through both contact and ingestion, and can be effective against slightly older caterpillars. It will cause the death of the insect in 1-2 days (roughly) due to improper nerve functioning. Spinosad should not be applied to flowering host plants, as it is highly toxic to pollinators, such as bees, before it dries. Once it dries, it is practically non-toxic to these non-target organisms.

Insecticides containing other active ingredients are also labelled for use against gypsy moth caterpillars, but the different risks associated with these active ingredients should be fully understood and taken into consideration prior to using products that contain them. Always completely read and understand the insecticide label. These active ingredients include, but are not limited to, acephate, acetamiprid, azadirachtin, Bacillus thuringiensis subsp. Aizawai, carbaryl, emamectin benzoate, insecticidal soaps, permethrin, and tebufenozide. Some of the products associated with some of these active ingredients are restricted use products. Homeowners looking for assistance in managing gypsy moth caterpillars should contact a Massachusetts licensed pesticide applicator and arborist for help.

Non-chemical options include banding trees for gypsy moth caterpillars and removing egg masses prior to hatch. Banding trees for gypsy moth caterpillars will not be 100% effective and may not yield the desired results. While the sticky band may catch some caterpillars, many others may still make it to the canopy of the tree to feed as they crawl up the tree trunk. Young, newly hatched caterpillars can also disperse through ballooning, or using a silken thread to catch the wind and blow to a new location. This can allow young caterpillars to move from tree canopy to tree canopy of hosts and never encounter the tree bands early on in their life cycle. Scraping the brownish-tan, fuzzy gypsy moth egg masses into a can of soapy water can be labor intensive and time consuming, and not all egg masses will be found or reachable. Some may be hidden from view or on the undersides of branches that are out of the reach of the homeowner.   

Another option for gypsy moth management is to do nothing and wait for the population to collapse. (see below: Are there other organisms that will affect gypsy moth populations?) This might not provide the best protection for valued ornamental plants, but may be a feasible management option to choose in largely forested areas. Ornamental plants suffering from multiple, consecutive years of gypsy moth defoliation may become weakened and more susceptible to secondary invaders or other organisms such as wood boring beetles and decay fungi that are attracted to otherwise weakened hosts. Add drought stress to that equation, and such plants may be even further compromised. 

Q: Are there other organisms that will affect gypsy moth populations?

A: Yes. Small mammals such as mice can have a large impact on gypsy moth populations when they are low. Certain species of native birds and insects may also act as predators of gypsy moth. Previously introduced parasitoids in the fight against gypsy moth including Ooencyrtus kuvanae, Cotesia melanoscelus, and Compsilura concinnata can attack certain percentages of the gypsy moth population, but even together their impact is not significant enough to reduce an outbreak.

The most effective organisms at regulating gypsy moth outbreaks are two pathogens - the fungus, Entomophaga maimaiga and the NPV virus. E. maimaiga is an insect killing fungus native to Japan that kills gypsy moth caterpillars. A first attempt to introduce it into North America was made in 1910 and 1911 for gypsy moth control, but it was thought that the attempt at that time failed. In 1989, the fungus was found to be killing large numbers of gypsy moth caterpillars in North America, perhaps from a separate introduction. Since 1989, E. maimaiga has been particularly successful in keeping gypsy moth populations out of an outbreak situation. Prior to that time, gypsy moth outbreaks occurred approximately every 10 years. The problems in Massachusetts seen in 2015 and 2016 are thought to be because of the very dry springs we have been experiencing, particularly in May and June. The fungus needs ample moisture at the right time in its lifecycle in order to effectively infect gypsy moth caterpillars. If enough rainfall is received, E. maimaiga is a density independent pathogen - meaning that typically, even in low populations of gypsy moth, this pathogen can be lethal to the caterpillars. The NPV virus, however, is density dependent, meaning that it requires a large population of gypsy moth in order to effectively infect and therefore reduce the population. The NPV virus tends to kill high populations of older caterpillars typically after they have done their feeding damage.    

Q: Where did gypsy moth come from?

A: Gypsy moth was brought to Medford, Massachusetts around 1868 or 1869 by Etienne Leopold Trouvelot. Trouvelot was an artist, amateur entomologist, and eventually an award-winning astronomer. He purposefully brought gypsy moth from France to his home in Medford for the purpose of studying them in hopes of using gypsy moth for silk production. Some of the larvae escaped and Trouvelot tried to notify the authorities, as he understood the potential degree of this accident. By 1889, the gypsy moth problem had spread and the local efforts to manage this insect began. Gypsy moth is a non-native, invasive insect in North America.   

Q: Where can I find more information? 

A: Check the UMass Extension Landscape Message for regular updates about gypsy moth and other insect pest activity throughout 2017. Information about egg hatch and defoliation seen in Massachusetts by this invasive pest will be shared under the Woody Ornamentals and Insects section. Further information about gypsy moth can be found in the UMass Extension Gypsy Moth Fact Sheet

Tawny Simisky, UMass Extension Entomologist

Plant of the Month

Cornus florida, flowering dogwood

Flowering dogwood is a beautiful low-branched deciduous small tree native to the eastern United States. It typically grows to 15-30 feet tall and wide with a rounded to flat topped crown. Plants have an attractive horizontal, tiered branching habit. Cornus florida has lovely 3-4 inch diameter flowers (bracts) in spring. The true flowers of dogwood are the insignificant tiny yellow or greenish button like clusters in the center. The tiny clusters are surrounded by showy petal like bracts that give the appearance of four-petaled flowers. The flowers are generally white, but cultivars can have pink or red flowers. The leaves of flowering dogwood are dark green, 3-4 inches long and turn to beautiful red to reddish purple fall color. The fruits are bright red, ripening in late September to October and persisting into winter. Fruits are not edible to humans but are frequently eaten by birds. Bark on the stem and older branches develops an alligator hide appearance that is very attractive in the winter landscape.

Flowering dogwood prefers acidic, well-drained soil that is high in organic matter. It does not tolerate poorly drained soil. The tree should be mulched to keep the soil moist and cool. It performs best in partial shade but can be planted in full sun. When planted in full sun, flowering dogwood tends to be bushier and produce more flowers. Cornus florida is not tolerant to stresses such as heat drought or salt. When stressed, they become susceptible to a number of diseases, the most severe being dogwood anthracnose (Discula destructiva). Stressed trees are also susceptible to powdery mildew, leaf spots and are vulnerable to dogwood borers.

There are several cultivars to choose from including:

  • ‘Cloud 9’ – Hardy. Reaches a height of 15 feet and may have a spread of up to 20 feet. Produces many white flowers (bracts) at an early age.
  • ‘Cherokee Princes’ – Produces large white flowers (bracts)
  • ‘Cherokee Chief’ – Produces deep red flowers (bracts)
  • ‘Rubra’ – Produces pink flowers (bracts)
  • ‘First Lady’ – Variegated yellow green foliage and white flowers (bracts)
  • ‘Pluribracteata’ – Produces double white flowers (bracts)

Cornus floridawhite flower  Cornus florida tree with white flowers Cornus florida with pink flowers Cornus florida bark

Geoffrey Njue, UMass Extension Green Industry Sustainability Specialist

Upcoming Events

Spring Blooming Tree and Shrub ID Walk
May 10 - 3:00 to 5:00 pm
Bowditch Hall, UMass Amherst 

With so many to choose from, it's hard to know what best to pick when investing in a new planting. Amanda Bayer, UMass Professor of Sustainable Landscape Horticulture, will show you key identification features for a variety of spring blooming trees and shrubs, with an emphasis on ornamental features, plus tips for tree and shrub identification and how to tell similar species apart. Approximately 25 plants will be covered along with appropriate siting and cultural practices.

For more details and to register, go to ag.umass.edu/events/spring-blooming-tree-shrub-id-walk


Additional Resources

Landscape Message - for detailed timely reports on growing conditions and pest activity

Home Lawn and Garden Resources

Find us on Facebook! https://www.facebook.com/UMassExtLandscape/

Follow us on Twitter for daily gardening tips and sunrise/sunset times. https://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.