Prune Your Oak Trees in Winter

In an earlier post we discussed oak wilt, which was identified for the first time on Long Island this summer in the Town of Islip. Unfortunately, additional reports of oak wilt have since occurred from several other towns in Suffolk County. In light of these reports, the DEC is urging homeowners to prune their oak trees in winter and not during the growing season. One way that oak wilt spreads is through insects (sap beetles are one of the main culprits), which can move the fungus from an infected tree to a healthy tree. During the warmer growing season sap beetles are active and attracted to the fresh wounds, increasing the chances of disease spread.

Learn more about oak wilt on the DEC website.

Register for Spring Gardening School

Join us for Suffolk County’s annual Spring Gardening School on Saturday, April 22, 2017, 8:30 a.m. to 4:00 p.m. Organized by Master Gardener Volunteers for the last 35 years, this beloved event kicks off the growing season for hundreds of gardeners who gather together for a day of learning and fun.

Spring Gardening School 2017 will be held at Longwood Senior High School in Middle Island, NY. All classes are taught by Master Gardener Volunteers and Cornell Cooperative Extension Educators. The day consists of workshops held during three sessions and offers classes for beginners to advanced gardeners. This year a keynote address on “Long Island Native Plants and Pollinators” will be presented by Polly Weigand, Executive Director of the Long Island Native Plant Initiative. You can sign up for such classes as Gardening with Chickens, Design & Install Drip Irrigation, How to Attract and Enjoy the Ruby-Throated Hummingbird, Low-Water Gardening, Seed Starting Demystified, and many, many more.

The fee to attend is $65 per person ($60 early bird, before March 1st), which includes free soil pH testing, a Long Island Gardening Calendar, a plant diagnostic clinic, gardening exhibits, and an early plant sale from some of the finest nurseries on Long Island; continental breakfast, delicious boxed lunch, raffles, and door prizes. Preregistration is mandatory; first come is first served. Here is a registration form with a full schedule of classes and their descriptions for you to download and send to us. We look forward to seeing you there!

Creating a Rain Garden

Do you want a garden that’s easy to install, looks good year-round, requires little maintenance, and helps prevent water pollution? Rain gardens are shallow depressions designed to soak up water and support trees, shrubs, and flowers that tolerate both wet and dry conditions. Often located near gutter downspouts or places where water puddles, rain gardens can also be landscaped into gentle slopes or run curbside along streets.

Giant hyssops, switchgrass, and goldenrod are some of the species growing in this rain garden at Cornell Plantations in Ithaca, planted next to its parking lot to absorb and clean polluted storm-water run off. Photo

Giant hyssops, switchgrass, and goldenrod grow in this rain garden at Cornell Plantations in Ithaca, planted next to a parking lot to absorb and clean storm-water runoff. Photo © Robin Simmen.

By absorbing the rain falling on your land, a rain garden can help reduce the storm-water runoff that pollutes our beaches, harbors, and estuaries. People sometimes confuse rain and water gardens. A rain garden is not a pond and won’t breed mosquitoes, which require 10 to 14 days in standing water to develop from eggs into adults.

The next time it rains, observe the direction of water runoff and where it collects on your property. Your roof may be directing most of the rain falling on it into gutters and downspouts feeding into a storm drain; if so, consider diverting this lost rainwater to irrigate a rain garden via underground piping, or construct a surface swale to channel this water to the garden. If your land slopes gently, you can create shallow terraces (one foot deep or less) for your rain garden or dig out a scallop-shaped bed for it in the hill.

The best plants for rain gardens are happy with a “drought and drench” lifestyle. Native plants are highly recommended because they are uniquely adapted to local weather fluctuations. Also, they require little or no fertilizer, are excellent food sources for pollinators, and provide habitat for birds, insects, and butterflies. Once established, their deep roots increase the water-holding capacity of the soil, hold it together, and prevent erosion. Water a rain garden as needed for the first year or so after planting. By the third year, you’ll never need to water it again!

For information on how to evaluate and amend your soil for a rain garden, do a percolation test to see how quickly water is absorbed, decide the dimensions of a rain garden, and prepare and plant the site, read the CCE Suffolk fact sheet on Creating a Rain Garden, and its companion  Native Plants for Long Island Rain Gardens.

Robin Simmen is a former Community Horticulture Specialist for CCE Suffolk. She can be reached at rlsimmen@gmail.com.

“Plants for Pollinators,” the LI Gardening Calendar for 2017

Now’s the time to buy the Long Island Gardening Calendar 2017, a perfect gift or stocking stuffer for the passionate gardeners in your life. Plants for Pollinators is filled with tips for creating pollinator-friendly gardens on Long Island. With beautiful photographs every month, this calendar features information on how to support bees, flies, wasps, butterflies, moths and birds by planting native habitat for them. Blueberries, strawberries, apples, carrots, broccoli, and pumpkins are among many plants that require pollinator services to produce fruits and vegetables — which means we need pollinators, too!

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A flower fly visits a Rosa virginiana, a native rose. Photo © Mina Vescera.

This high-quality calendar discusses how to analyze your landscape to plan a pollinator garden and how to include nesting habitat for insects, and gives you a resource list of organizations and websites where you can learn more about sustainable horticulture and pollinators. There’s even a list of where to buy native plants on Long Island! Purchase calendars at the front desk at CCE Suffolk, 423 Griffing Avenue in Riverhead for $5 each; or use this order form to have them mailed to you for $7 each to cover their cost with postage.

Whether you’re a beginner or advanced gardener, there’s something here to inspire everyone who wants protect and support pollinators. It’s time to start planning for next year’s garden, and calendars are limited, so pick up or order Plants for Pollinators today!

Robin Simmen is Community Horticulture Specialist for CCE Suffolk. She can be reached at rls63@cornell.edu or at 631-727-7850 x215.

Apply Now for 2017 Master Gardener Volunteer Training

CCE Suffolk trains Master Gardener Volunteers to provide the public with gardening programs and activities that draw on the horticultural research and experience of Cornell University. MG Volunteers receive research-based instruction and are kept up-to-date through continual exposure to the latest developments in environmental horticulture. In return, they agree to share their knowledge with neighbors by volunteering to do community service. After completing the training course and volunteering for 125 hours, they become certified as CCE Suffolk MG Volunteers. Suffolk County’s MG Volunteer Program, along with similar programs in other counties in New York State, is directly linked to Cornell University as part of its National Land-Grant College charter. This tie to Cornell provides MG Volunteers with state-of-the-art gardening knowledge.

MG Volunteer trainees learned how to create healthy soil by sheet mulching into raised beds at the Children's Garden.

2016 MG Volunteer trainees learned how to create healthy soil by sheet mulching compost materials into raised beds. Photo © Robin Simmen.

Anyone who enjoys gardening and has a desire to share knowledge and skills in their community can apply by October 31, 2016 to become a MG Volunteer next year. Every year hundreds of these service-minded folks from Suffolk County do the following:

  • Organize a Spring Gardening School for the public, including workshops, exhibits, and a plant sale
  • Table with gardening information at community events
  • Cultivate the land and teach youth at the Children’s Garden at Suffolk County Farm
  • Design and help maintain community beautification projects, demonstration gardens, community gardens, and school gardens
  • Offer gardening talks and classes at public libraries, schools, and for interested groups
  • Create and participate in programs for senior citizens, youth, and the physically and mentally challenged
  • Teach the proper care of lawns, shrubs, trees, and flowers, and how to grow fruits and vegetables
  • Install exhibits and provide gardening information at flower shows and events such as the Suffolk County Farm PumpkinFest and the Bayard Cutting Arboretum Fall Harvest Festival

The next training course for new MG Volunteers is planned for 2017, beginning February 1 and ending June 28. We have revised the curriculum and weekly schedule to provide more hands-on training and make it accessible to people who work Monday through Friday. Starting February 1, weekly Wednesday evening lectures will be held 5:30-8:30 p.m. at CCE Suffolk, 423 Griffing Avenue in Riverhead. Starting April 1, Saturday morning classes will also be held 9:00 a.m.-noon in the field (weather permitting) every other week at various locations from Amityville to Riverhead until the course ends June 28.

The cost of this comprehensive gardening course for community volunteers remains $375 with an additional $125 deposit, refunded upon completion of 125 hours of volunteer service. Download the application here. For more information, please call or email me soon; the deadline to apply is October 31.

Robin Simmen is Community Horticulture Specialist for CCE Suffolk. She can be reached at rls63@cornell.edu or at 631-727-7850 x215.©

Does Your Basil have Downy Mildew?

If your basil leaves have turned yellow and display a dark-brown sooty growth on their underside, then your plants have downy mildew, a regularly occurring disease on Long Island since it first appeared here in 2008. Click on the photo gallery on my Vegetable Pathology – Long Island Horticultural Research & Extension Center webpage to look at pictures of diseased basil to help determine if your herbs are affected.

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Photo © by Dr. Margaret McGrath

There’s also lots of information about basil downy mildew on my webpage at Cornell Vegetable MD Online. If you’d like to log a report of your diseased basil to help me with a study on basil downy mildew, click here at Basil Downy Mildew Monitoring Records 2016. And for a national perspective about where it has appeared in the United States, visit Where in the USA is Basil Downy Mildew? This is a good web reference to visit in the future to learn when other gardeners are starting to find the disease on Long Island and elsewhere, too.

Downy mildew is hard to manage in basil plants. My recommendation for gardeners is to grow basil in pots and not expose them to high humidity (above 85%) which the pathogen requires to be infectious. Low humidity can be maintained by keeping plants indoors overnight and on rainy days. For more information, visit my webpage How Gardeners Can Manage Downy Mildew in Basil

Starting in late July, I grow my second planting of basil in pots because downy mildew typically begins developing for me on Long Island during August. Also, since basil is very cold sensitive, bringing plants into a warm house overnight maintains basil quality when night temperatures start dropping to below 55F.

If your basil is still green and healthy, consider yourself lucky and go knock on wood! And then drop me an e-mail. Cheers!

Dr. Meg McGrath is Associate Professor at Cornell University’s Long Island Horticulture Research and Extension Center in Riverhead, New York, where she conducts research and extension activities to help farmers manage diseases.

Oak Wilt Disease Spotted on Long Island

Earlier this month, the NY State Dept. of Environmental Conservation issued a press release about the first known case of oak wilt, a serious tree disease, on Long Island. In June an arborist spotted symptoms of the disease in four trees in the Town of Islip and submitted samples from them to the Cornell Plant Disease Diagnostic Clinic, where the disease was identified. No treatment for oak wilt is known to contain and kill it other than removing infected trees and surrounding host oak trees, which was done in Islip. This is the second place in New York where the disease has been seen, the first being in Schenectady County in 2008 and 2013.

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Note different patterns of infection on the white oak leaf (A), with its round lobes, and the red oak (B), with its pointy lobes.

Oak wilt appeared in the Great Lakes Region in 1944 and has since spread throughout the eastern United States, killing thousands of oak trees each year. Caused by the fungus Ceratocystis fagacearum, the disease creates blockage in the xylem vessels (sapwood) that conduct water within trees, slowing water delivery until leaves wilt and drop off. Red oaks succumb more quickly to the disease than white oaks and typically die within a few weeks of infection.

Oak wilt spreads three ways:

  • through underground root systems
  • through beetles that colonize infected oak trees and carry oak wilt to other trees
  • through the movement of firewood within and out of areas where trees are infected

If you witness unusual leaf wilting and drop off on oak trees where you live, please call the NYSDEC Forest Health Information Line toll-free at 1-866-640-0652 to report it.

To learn more about the symptoms of oak wilt and how to submit samples of oak trees suspected of having it, click here to visit the 2016 Oak Wilt Update  on the Cornell Plant Disease Diagnostic Clinic website. This You-tube video Oak Wilt in NY (made by Dr. George Hudler in 2008 after the first outbreak of oak wilt upstate) is very helpful in walking you through how to identify red and white oaks and how to prepare plant samples to submit for diagnostic testing.

Robin Simmen is Community Horticulture Specialist for CCE Suffolk. She can be reached at rls63@cornell.edu or at 631-727-7850 x215.

Gardening in a Drought

As of the last week of July 2016, the US Drought Monitor classifies most of Suffolk County as being in a severe drought. According to my precipitation records, Riverhead will need 10 inches of rain by the end of October to be on par with what we consider average. It’s currently raining, and let’s hope it keeps up!

Using mulch is key to waterwise gardening and healthier plants. Photo c Robin Simmen

Using mulch is key to water-wise gardening. Photo © Robin Simmen

Living on Long Island, we gardeners wait all winter to get outside and enjoy our yards. Drought presents us with a moral dilemma: Do we continue watering so we can enjoy the bountiful fruits of the vegetable garden, bright blooms, and green grass? Or do we reduce our irrigation and let nature take its course? Here are some tips for water-wise gardening regardless of the weather:

  • Mulch! Mulch everything! Mulch your landscapes beds, your flower pots, and your raised beds. Whether you use wood chips, straw, or grass clippings, mulch helps regulate soil temperatures and reduce evaporation. Providing a 3-inch mulch layer can reduce plant needs for irrigation by up to 50 percent. Review your choices for mulch by reading our fact sheet Types and Uses of Mulch in the Landscape.
  • Plant early. If you’re planting new perennials, trees, and shrubs, plan to get them in the ground either in the fall or very early in the spring, as soon as the ground is workable. This gives plants more time to recover from transplanting and develop roots. Fall planting generally takes advantage of the season’s rainfall, but remember we’ve had very dry falls recently and many plants require irrigation until they go dormant. Warm-season vegetable plants, such as tomatoes and peppers, will still have to wait until spring nighttime temperatures are consistently above 45°F.
  • Garden in raised beds. Planting vegetable gardens in raised beds gives you more control over their growth and water. You can amend the soil in raised beds more fully, creating environments where your soil holds moisture better. Soils rich with organic matter hold onto water and nutrients better than sandy soil.
  • Weed. Keep your beds free of weeds. Not only do they compete with your plants for moisture, but they rob them of soil nutrients and sunshine if left to grow tall. Some weeds even serve as hosts to diseases and insects that prey on your plants.
  • Water efficiently. Plants absorb water through their roots, so concentrating irrigation in the soil zone is crucial. Avoid overhead watering from sprinklers as these are not as efficient as soaker hoses and drip irrigation, and foliage wetness often exacerbates fungal diseases. Drip irrigation can reduce watering needs by up to half. The key to healthy plants is deep, infrequent watering. Try to water in the morning when the natural dew is set. Morning temperatures are cooler and evaporation is lower.
  • Allow your lawn to go dormant. The majority of grasses we grow for lawns are considered cool season grasses (bluegrass, perennial ryegrass and fescue). These grasses are green and grow actively in the spring and fall but prefer to go dormant in summer heat. Letting your lawn go dormant will not harm it and is actually beneficial to both its grasses and our environment. If a dormant lawn is not possible, be sure to follow the rules of deep, infrequent watering, mowing no less than 3 inches, minimizing fertilizer applications, and leaving your clippings on the lawn (contrary to popular belief, clippings don’t contribute to thatch build up and help conserve water in your lawn.)
  • Monitor your plants. Not everything needs supplemental irrigation. If your established landscape doesn’t show signs of drought stress, assume that the plants are finding water.
  • Put the right plant in the right place. If established trees and shrubs are struggling with this drought, they are probably planted in the wrong spot. For example, Japanese cut leaf maples and flowering dogwoods are understory trees. They enjoy morning sun and shade throughout the hot hours of the day but are often poorly planted in the middle of a hot lawn. Take care to site plants where they will perform their best.
  • Recycle your water. If you boil water for pasta, or you have some water left in a drinking glass, collect that water in a bucket to be used in the garden. Once you become aware of wasteful water usage, you’ll quickly discover ways to conserve and recycle.

Information on drought-tolerant plants and more can be found on our website in this brochure: Waterwise Gardening.

Sandra Vultgaggio is Horticulture Consultant for CCE Suffolk. She can be reached by email at sib7@cornell.edu or by phone at 631-727-7850 x387.

Growing Vines in the Landscape

When gardeners think of flowering plants, what usually comes to mind are annuals, perennials, and a few trees and shrubs. Although often overlooked, vines also have great potential in home gardens as they can create shade on pergolas, add vertical interest to arbors, adorn fences, or even serve as decorative ground covers.

Our wonderful native honeysuckle attracts hummingbirds.

Our wonderful native honeysuckle attracts hummingbirds.

To select a vine, first consider how it grows. Does it twine like a honeysuckle vine? Does it cling with aerial roots like a climbing hydrangea? Or does it produce tendrils like a clematis? Knowing how the vine grows will dictate the type of support you need to provide for it. Also think about the site: Is it sunny or shaded? Are you trying to attract wildlife? Do you prefer an evergreen plant? Here are a few vines worth considering:

Honeysuckle Vine (Lonicera sempervirens)

Our native honeysuckle vine is a great choice for a sunny site. It will happily twine its way in and out of a picket or chain-link fence, arbor, or trellis. As the botanical name suggests, this vine is evergreen in a mild winter. Honeysuckle vine is among the first plants to bloom in spring, serving as a bright beacon for Ruby-Throated Hummingbirds making their way back from southern climes where they overwinter. This vine grows 15 feet or taller and can withstand hard pruning. Some cultivars bloom continuously with red, orange, pink, or yellow flowers from spring until fall, providing all-season interest. Honeysuckle is prone to powdery mildew, but siting it in full sun with good air movement will keep the plant in good health. Aphids can sometimes be a problem. Be careful: Don’t confuse this native honeysuckle for the invasive, Asian species, Lonicera japonica!

Dutchman’s Pipe (Aristolochia macrophylla)

Dutchman’s pipe is another great choice if you’re looking for a native vine to cover a large area. This woody-stemmed, twining vine requires a strong trellis, wall, or pergola to support it. It will tolerate sun to shade in any garden setting, from a manicured garden to a tough urban site. Dutchman’s pipe was a popular choice in the 19th century, draping over large Victorian homes. The vine produces small, inconspicuous, purple-brown flowers that produce a unique odor and are often pollinated by flies that crawl into the “pipe” and get stuck within the hairs inside the flower. Once a pollinator is caught, the flower hairs wither and the insect can crawl out, covered in pollen. If you’d like to invite pipevine swallowtail butterflies to your garden, this is their host plant.

Dutchmans pipe creates a dense barrier of foliage.

Dutchmans pipe creates a dense barrier of foliage.

Passion Flower (Passiflora caerulea)

Blue passion flower, also known as hardy passion flower, is a unique option for a protected site. This passion flower is said to be hardy to USDA zones 7 and 8, but a harsh winter will probably knock this vine back to the ground. Passion flower climbs by tendrils, sometimes reaching 20 feet and higher. Unique purple-blue flowers are produced on new growth on and off throughout the growing season. If you’re looking for a native variety, Passiflora incarnata ‘Maypop’ is a hardy passionflower up to USDA zone 6. Pale-lavender flowers bloom throughout most of our growing season on Long Island. Maypop is also the host plant for the Gulf and Variegated Fritillary butterflies!

Climbing Hydrangea (Hydrangea petiolaris)

Climbing hydrangea is a great alternative to English ivy. Like ivy, this clinging vine uses aerial roots to attach itself to porous, vertical surfaces. You’ll be graced by large, lacy, white fertile flowers surrounded by a circle of larger, white sterile flowers in summer (think lacecap hydrangea). Plant a climbing hydrangea in sun to partial shade in rich, well-draining soil. Though this vine grows well on the trunk of a tree, it is not healthy for a tree to bear the weight of another plant. Instead of a tree, choose surfaces like wooden stockade fences, stucco siding, and stone walls. Climbing hydrangea is notorious for starting off slowly and establishing its root system for a few years before it takes off. Have patience, it’ll be worth the wait!

Morning Glories Ipomoea spp.

If you like to change it up every year, consider growing annual vines such as these in the morning glory family: moonflower (Ipomoea alba), cardinal climber (Ipomoea x multifidi), cypress vine (Ipomoea quamoclit), and the traditional morning glory (Ipomoea tricolor). Moonflowers open at night, providing bright-white, fragrant blossoms for evening dinner parties. Morning glories bloom in the morning and begin to fade by mid-afternoon. Gardeners often combine moonflower and morning glories together on one trellis to provide a continuous bloom day and night. Cypress vine and cardinal climber can be added for a pop of bright red to attract hummingbirds and other pollinators. Ipomoea spp. can be direct-sowed in a sunny site with good drainage. They grow rapidly, twining in and out of a trellis, arbor, or fence.

Cypress vine makes a great splash of color on a wooden fence.

Cypress vine makes a great splash of color on a wooden fence.

These are just a few of the many vines we can grow on Long Island. For more options and information on growing vines in home landscapes, check out our CCE Suffolk Horticulture Fact Sheet: Flowering Vines for Long Island: Indoors and Outdoors

Sandra Vultgaggio is Horticulture Consultant for CCE Suffolk. She can be reached by email at sib7@cornell.edu or by phone at 631-727-7850 x387.

Tomato and Potato Late Blight: What to do NOW!

Late blight is arguably the worst problem that can appear in a vegetable garden! Its highly contagious and very destructive nature means everyone growing susceptible tomato and potato plants – gardeners and farmers alike – needs to take action to prevent late blight from occurring and needs to respond quickly when it appears. The major epidemics of this disease on Long Island in 2009 and 2011 are thought to have started with just a few infected plants.

Sungold cherry tomato can be devastated by late blight, as it was here in my garden in 2013.

SunGold cherry tomato can be devastated by late blight, as it was here in my garden in 2013. Photo by Meg McGrath.

Early Season Action Steps to Prevent Late Blight:

  • Select varieties that have resistance to late blight. For example, the popular SunGold cherry tomato is susceptible to it; Jasper cherry tomato is not. Information about tomato varieties can be found at http://www.extension.org/pages/72678/late-blight-management-in-tomato-with-resistant-varieties#.VRNfGkZwfsM
  • Plant certified potato seed. Do not plant potatoes from last year’s garden or from the grocery store. There is a higher probability for the late blight pathogen (Phytophthora infestans) to be in “table-stock” potatoes.
  • Destroy any potato plants that grow as “volunteers” in compost piles or in the garden from potatoes not harvested last year.
  • Inspect tomato seedlings carefully for symptoms before purchasing them. The pathogen as it exists in the United States is not known to survive in tomato “true” seed and then infect the seedlings, so if you grow your own seedlings, late blight is not a concern until they are planted. Seedlings become infected by growing near other affected plants.
  • Become knowledgeable about the different symptoms of late blight and its imitators. I have posted photographs of this at http://livegpath.cals.cornell.edu/gallery/tomato/tomato-late-blight/.
  • Monitor the occurrence of late blight in the United States at usablight.org. You can sign up on that website to get an alert by text or e-mail when a report has been logged nearby, so you can be one of the first to know when late blight has been found on Long Island.
  • Inspect your tomato and potato plants for symptoms at least once weekly.
Inspect tomato plant leaves for symptoms of late blight, such as the discoloration you see here. Photo by Meg McGrath.

Inspect tomato plant leaves for early symptoms of late blight, such as the discoloration shown here. And then act fast! Photo by Meg McGrath.

What to do when late blight symptoms are found: Immediately call our Horticulture Diagnostic Lab at our hot line at 631-727-4126 from 9 a.m. to noon, Monday through Friday. Alice Raimondo and Sandra Vultaggio, our Horticulture Consultants, can help determine whether you do, indeed, have late blight, and answer questions about proper handling of an outbreak.

Best management steps for dealing with disease are based on knowledge of the pathogen’s biology and life cycle. The late blight pathogen in the United States is not known to reproduce sexually, as it does elsewhere in the world including in parts of Europe. Where it does reproduce sexually, it produces a type of spore (oospore) that enables the pathogen to survive in true seed and in soil; consequently, rotation is an important management step in Europe, but this is not necessary for controlling late blight in the United States.

Dr. Meg McGrath is Associate Professor at Cornell University’s Long Island Horticulture Research and Extension Center in Riverhead, New York, where she conducts research and extension activities to help farmers manage diseases.