Author Archives: dmc72

Summer Session for the Advanced Training for LI Gardeners is Back!

Have you ever wanted to take the “Master Gardener” course but cannot commit to the lengthy training or volunteer work?

Our popular online course is back- CCE Suffolk will again offer a 9-week online course for our gardening community, based on the horticultural research and experience of Cornell University specialists and experts in their field.

The Advanced Training for LI Gardeners (ATLIG) offers many of the same horticultural topics included in the Master Gardener Volunteer training, including botany for gardeners, soils, beneficial insects, composting, vegetable and fruit gardening, lawn care, plant diseases, climate resilient gardening, managing wildlife, pests and much more.

You can download more information and the Registration Form here: ATLIG Summer 2019 Registration

The online course will begin on June 24 and end August 23, 2019. There are no sessions to attend in person.

Contact Donna Alese Cooke at for more information. Limited space is available.

It’s Not too Late to Join our Spring Gardening School!


Join us for our full day of Gardening Workshops at Suffolk County’s annual Spring Gardening School on Saturday, April 13, 2019. Organized by Master Gardener Volunteers for the last 37 years, this beloved event kicks off the growing season for hundreds of gardeners who gather together for a day of learning and fun.

This year’s Spring Gardening School will be held at the Riverhead Middle School in Riverhead, NY. All classes are taught by Master Gardener Volunteers, Cornell Cooperative Extension Educators and local experts.

Download the registration form at×11.pdf?1549037029

There is still room in these sessions:

1D- Food Security: Issues & Potential Solution

2C- What’s Wrong with This Picture?

2D-Invasive Woodland Weeds: Top Ten Problems on Long Island

3B-Gardening with Chickens

4A- Indoor Plants

4B- For the Beginner–Gardening 101

Extended Sessions

EXAM 1: Design & Install Drip Irrigation

EXAM 2: Nature’s Colors in Your Hands

EXAM 3: Field of Poppies Botanical Art

EXAM 5: Organic Landscape Maintenance

EXPM 1: Floral Design for Beginners & Intermediates

EXPM 2: Make & Bake Herb Bread & Butter,

EXPM 3: Field of Poppies Botanical Art

EXPM 4: Pruning Roses and Hydrangeas: No More Flowerless Plants!

Classes fill quickly! Download the brochure here which has the registration form to mail back to us. We look forward to seeing you there!

New Online Course for LI Gardeners

Have you ever wanted to take the “Master Gardener” course but were unable to attend daytime trainings or have time to volunteer?

CCE Suffolk is now offering an 8-week online for our gardening community, based on the horticultural research and experience of Cornell University specialists and experts in their field. The Advanced Training for LI Gardeners (ATLIG) offers many of the same horticultural topics included in the Master Gardener Volunteer training, including botany for gardeners, soils, beneficial insects, composting, vegetable and fruit gardening, lawn care, plant diseases, climate resilient gardening, managing wildlife, pests and much more.

Visit our website at for ATLIG schedule and registration information, as well as information on our annual Spring Gardening School. The online course will begin on February 19 and end April 14, 2019. There are no sessions to attend in person.

Contact Donna Alese Cooke at for more information. Limited space is available.

From the Horticulture Diagnostic Lab: Emerald Ash Borer Found in Suffolk County

Photos of trees in varying stages of health are not a new thing for the Horticulture Diagnostic Lab to receive. Homeowners often contact us wanting a diagnosis of their sick or “dying” tree. I recently responded to an email from a homeowner from the north fork of Long Island, inquiring about borer holes on three deciduous trees, and I requested he send photos. When the photos arrived, the injury to the trees was unlike anything I had seen before; extensive woodpecker activity called “blonding” (see photo below).

The trees have furrowed bark, opposite branching and a somewhat weeping habit, which is characteristic of ash trees, and although I wasn’t able to see the emergence holes from the photos, my heart sank. This had to be the workings of an insect called the Emerald Ash Borer (EAB), which up until now had not been found out in Suffolk County. Confirmation of the tree species as ash and identification of EAB followed just a few days later by our local Cornell Entomologist Dan Gilrein. EAB has arrived.

With no known sightings of this insect in any other parts of Suffolk or Nassau counties, one wonders how did this insect found its way all the way out to the north eastern part of Suffolk County with no stops in between? Ash trees do not make up our native forests here on Long Island, but varying species of ash (genus Fraxinus), have been planted as street trees in many locations and planted on homeowner properties as well. The movement of infested firewood, much like other invasive insects such as the Asian Longhorned Beetle, or diseases such as Oak Wilt, is the most likely answer. Human activities provide the transportation for these hitchhikers.

In the community where the insect was found, many of the homes are second homes or vacation homes, so perhaps firewood was brought in from another location where EAB is well established. I’m writing this to hopefully make more people aware that it is illegal to move firewood more than 50 miles from its source and that by law untreated firewood cannot be brought in to New York State. For more information about the specific regulations pertaining to moving firewood you can click on the following link to the New York State Department of Environmental Conservation website; Don’t contribute to the growing spread of destructive invasive pests. Protect our trees!

At the time of this writing it isn’t known the extent of the EAB infestation here in Suffolk County, but as always our Horticulture Diagnostic lab is here to help! Emerald Ash Borer can also attack a related species of tree called the fringetree which is a very ornamental flowering tree. For specifics on this highly destructive insect pests please feel free to visit the New York State Department of Environmental Conservations website for their EAB fact sheet here;

This beetle is difficult to detect before extensive damage has been done, so if there are valued ash trees on your property you should likely consider protecting them with the appropriate pesticide. The New York State Department of Environmental Conservations press release regarding the finding of the Emerald Ash Borer can be found here;

If you suspect you may have EAB on your property or are having a problem with you trees, feel free to give us a call. You can find our contact information here;

Article by Alice Raimondo, CCE Suffolk Horticulture Consultant


From the Horticulture Diagnostic Lab: Boxwood Blight

With the year drawing to a close and cold weather settling in, our diagnostic lab in Riverhead remains busy. This year has been a banner year for boxwood blight, with the lab seeing over 85 positive samples come in. The humid weather throughout the summer, followed by a particularly rainy fall created the perfect environment for this disease to thrive in our landscapes.

Before you go run out to your boxwoods to see if they’re okay, know that if you haven’t brought in any new boxwood, pachysandra or Sarcococca (sweet box) plants into your landscapes since 2011, your plants are probably okay. If you are particularly fond of the boxwoods on your property, you will  want to familiarize yourself with some of the common symptoms:

  • Black or dark brown leaf spots
  • Black or dark brown steak-like lesions on stems that almost resemble markings from a permanent marker
  • Sudden and dramatic leaf-drop.
  • Green stems that are defoliated.

We have some very helpful links and photos for you to check out on our website:

Photos above are courtesy of Mina Vescera, CCE Suffolk Nursery and Landscape Specialist. Photo to the left, Boxwood Blight spots; and on the right, Boxwood Blight canker

To prevent this disease from striking your boxwood, we recommend not planting new boxwoods, or, if you do, only purchase plants from a trusted source. Only use clean pruning tools when shearing or pruning your boxwood. Tools can be disinfected by cleaning with a 10 percent bleach solution (9 parts water to 1 part bleach)- wipe off tools to remove debris, soak for 10 minutes in 10% bleach, and rinse in clean water before use. Leaves that fall from boxwood are small and sticky – be vigilant of leaves attached to shoes, gardening gloves and tools. Make sure your boxwoods are sited in the appropriate conditions: full sun with good air circulation, irrigated with soaker or drip hoses and not overhead irrigation. Boxwoods are more likely to become infected in continuously wet conditions.

If your boxwoods are looking unthrifty, it doesn’t necessarily mean they are infected with boxwood blight. Contact us at the Horticulture Diagnostic Lab with photos and samples. Our publication here, Photographic guide of Boxwood Pests & Diseases on Long Island, will help you troubleshoot the common problems we encounter.

Should your boxwood fall victim to boxwood blight, your best course of action would be to pull out the plants and destroy them. Fungicides may help protect plants from new infections but they are costly and diligent applications are necessary and not always successful. Severely pruning back plants can be helpful, but with the slow growth-rate of boxwoods, you may be looking at a sad plant for a long time. Until effective management solutions are discovered, your best bet will be to think outside the box…wood. You can find some good alternatives on our factsheet.

Sandra Vultaggio, CCE Suffolk Horticulturist

photo courtesy of Margery Daughtrey, Cornell University


“Climate Change, Science, Communication and Action” Online Course from Cornell University

Cornell University Civic Ecology is once again offering a 6-week online course on “Climate Change, Science, Communication and Action” starting this week, 9/11/18. Please share with anyone you know may be interested! Registration remains open this week at:
Suffolk County residents who enroll in this course are welcomed to join our local Suffolk CCE Community Action group, where we will provide educational resources and additional in-person trainings that address Gardening in a Warming World.
Contact Donna Alese Cooke at to learn more about our local Suffolk CCE Community Action group, and the upcoming free in-person classes that will be available to Suffolk County residents participating in the “Climate Change, Science, Communication and Action” online course. 

What are those Webs in the Trees?

Fall webworm is all around on Long Island now.  Our Diagnostic Lab is getting many complaints about a wide variety of trees and shrubs with lots of webbing, defoliation and browning leaves.

According to Sandra Vultaggio, Horticulturist in our CCE Suffolk Diagnostic Lab, this pest has been particularly successful this year in part due to the high humidity we’ve experienced. Since this is a late-season pest it does not tend to affect the health of the tree. It is more of an aesthetic issue when the brown leaves and webbing occur. For this reason we do not often recommend pesticides. Once the caterpillars are finished feeding, which takes roughly 6 weeks, they will fall to the ground to pupate over winter. It may be wise to do a thorough fall cleanup of leaves and debris around the trees this year.

Dan Gilrein, Extension Entomologist adds that some herbaceous plants are affected as well. Some may confuse this with gypsy moth, which doesn’t produce webbing and is not active this time of year, or (eastern) tent caterpillar, which is active in spring mainly on cherry and apple, ornamental varieties of these, and some related plants. Fall webworm is a native insect and its populations go in cycles. It’s wide host range includes over 400 plants. This particular ‘outbreak’ is the largest he has seen, though similar (short-lived) population explosions have been observed elsewhere. Fall webworm levels were high in parts of the Adirondacks last year, for example, but have since collapsed for the most part. Dan is not sure know why these population swings occur, but they probably have to do with direct and/or indirect impacts of environmental conditions on  the insect, its natural enemies, and possibly its hosts.

While the webbing and damage are very ostensible, the actual harm to the plants is probably much less.  At this time of year the foliage has done most of its ‘work’ and will be declining soon. There might be some concern for plants that are being heavily defoliated, were in poor condition, or just recently planted, but generally plants should grow normally next year. The good news is this insect has many natural enemies (one author refers to it as a ‘parasitoid hotel’), so the numbers are expected to be much less next year. Ways to deal with this are:

  • Remove webbing and caterpillars by hand which will improve the appearance immediately.
  • Prune out infested branches. This is the last alternative, as it can damage the plant, spoil the appearance, and open wounds.
  • Contact a consulting arborist or landscape professional for assistance, who can assess and handle the job.

Photo courtesy of Master Gardener Holly Sisti

Be on the Lookout for these Vegetable Garden Diseases!

Look out for these garden diseases! See symptoms? Please report!

Occurrence of a couple important diseases of vegetables and basil is monitored in the USA every year to be able to inform growers when they need to be prepared for them to develop in their crops. Their occurrence is variable and impact is great, thus the importance of monitoring, which is done primarily by plant pathologists working with growers. Gardeners can access this information, thereby also benefiting, and they can play a very important contributing role by reporting when these diseases occur in their gardens. Some gardeners already have been! I have lots of photos to help with identifying these plus other diseases at: and information about them at Make sure to take photos to document your report.

Late blight of tomato and potato. Occurrences are mapped at At this webpage anyone can sign up to receive alerts when late blight has been confirmed near them; the alert system is not just for growers.

Late blight on tomato

Downy mildew of cucumber, squash and other cucurbits. In addition to information about occurrences, at there is a map-based forecasting system predicting where the pathogen is likely to develop next. There is also an alert system gardeners can utilize.

Downy mildew on cucumber

Downy mildew of basil. Reporting presently is done to a spreadsheet at  A map-based webpage is being developed similar to that for the other two diseases.

Downy mildew on basil

Take advantage of these great resources, and please contribute reports to increase the value of monitoring and our knowledge about occurrences of these important diseases.

Dr. Meg McGrath is an Associate Professor at Cornell University’s Long Island Horticulture Research and Extension Center in Riverhead, New York.

Not sure of the disease on you vegetable plants? Contact our Horticulture Diagnostic Lab and drop off a sample for diagnosis. For current hours, visit:



New Online Master Gardener Volunteer Training

No need to wait until you retire to take the Master Gardener Training program! New this fall, CCE Suffolk will be offering an online, hybrid training program that is designed for you to learn at your own pace, while easily fitting into your busy schedule.

Starting in September of 2018, the program will include all of the horticultural topics and hands-on training needed to become a Master Gardener Volunteer for Suffolk County Cornell Cooperative Extension. Monthly weekend in-person trainings will take place one Saturday each month from September 2018 through March 2019. Now is the perfect time to take the first step, and join our very dedicated group of expert gardeners!

See our new brochure to learn more about the Master Gardener Volunteer program.

Download the application for the 2018-2019 training here.

Questions? you can email Donna Alese Cooke at or call her at 631-727-7850 ext 225

Master Gardeners volunteering at Spring Gardening School



Landscape Trees with Beautiful Bark

Sycamore bark

With spring rapidly approaching there’s no better time to appreciate the silhouettes of our trees, especially those with attractive bark. This is a valuable ornamental feature often overlooked. While you are likely familiar with some of the larger trees that have striking bark, such as American or European beech, American sycamore or London Plane tree, there are many trees suitable for smaller landscapes which will catch your eye.

Japanese stewartia

Perhaps you are familiar with Stewartia psuedocamelia, or the other Stewartia species which have white camellia-like flowers in the early summer. But did you know that as they mature they develop an exfoliating bark in a patchwork of copper, tan, olive and lavender? Stewartia spp. are typically pest free and offer fall color too. Every yard should have one! Another tree offering bark in similar colors are the Crape Myrtles, Lagerstroemia indica hybrids. Crape myrtles are widely known for their late summer flowers in shades of pink, red, purple and white. When looking for a crape myrtle for your landscape select varieties best suited for our colder winters and then chose a flower color.

River Birch Bark


Maybe you have a wet site where many trees do not do well. I have just the solution for you, and it has attractive peeling bark to boot! The tree I’m referring to is called a river birch, Betula nigra. Young trees have papery bark in shades of cream, salmon, orange brown, and cinnamon brown which peels freely. As the tree matures the trunks become dark reddish brown to gray-brown in color with plate-like scales. River Birch also boasts resistance to the bronze birch borer, a devastating pest of many other beautiful birch trees.

A lesser known tree with highly ornamental bark is the Paperbark cherry, Prunus serrula. Much like most other flowering cherries, its white flowers are short lived and it may be prone to disease and insect pests, but the bark is incredible! I came across this tree in the New York Botanical Garden and was wowed! The bark is a glistening coppery red-brown, looking more like polished copper than living bark. I’m still contemplating including this one in my own landscape despite the pest management it will likely require.

Birch bark Cherry

Acer griseum

Mature Kousa dogwood bark


Before leaves and flowers emerge this spring, get out and really look at your trees. Botanical gardens and arboretums are a great place to see some of these trees and others that are especially beautiful in winter. Take notes and photos. Consider planting one or more of these trees with beautiful bark to give your landscape four season appeal!

Article and photos by Alice Raimondo, CCE Suffolk Horticulture Consultant