Category Archives: Waterwise gardening

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.

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.

Are you damaging your vegetable garden soil?

The rototiller is a popular tool used by home gardeners to control weeds, incorporate fertilizer and lime, and loosen up the soil for planting. While valuable for some purposes, it is important to recognize that rototilling does have a dark side: Earthworms and soil microbes, important for good soil health, are damaged by it. And organic matter in the soil is broken down and lost.

Farmers have learned about the negative impacts of rototillers and other tillage tools they regularly use. Today many are adopting “reduced tillage” practices to protect their soil. Cornell Cooperative Extension agriculture staff are working with Long Island farmers to help them change these practices successfully.

Since I work with farmers and CCE agriculture staff, I understand the importance of good soil health. So I decided to implement what I learned at work in my home vegetable garden, pictured below. I am excited about how my garden soil has improved. Its organic matter has increased, there are a lot more earthworms, and the soil is very friable, which makes it easy to dig holes for transplanting.

Adding a mulch cover of shredded leaves and grass from my yard and reduced rototilling has led to healthier soil and plants in my garden. Photo by Meg McGrath.

Doing less rototilling and using a mulch of plant materials from my yard created healthier soil in my vegetable garden. Photo © Meg McGrath.

Here is what I do now to protect soil health. First, I rototill only where I am directly seeding, which is currently just peas. I used to have my husband till the whole garden each spring with our big hand rototiller. Now we use a small rototiller to prepare our rows for the peas, tilling only the soil where I plant seeds and not disturbing the walkways between these rows.

Second, I cover the vegetable garden with shredded leaves and fresh grass clippings from the rest of the yard. This provides excellent weed control, so I don’t need to use the rototiller for controlling weeds. And this free mulch is a good source of organic matter that earthworms digest and move into the soil. I have a bagging, mulching lawn mower for collecting material for this ground cover. I just rake the mulch out of the way when I plant. I use a chipper-shredder to turn last year’s dead flower stalks and ornamental grasses into straw mulch to place around the base of the vegetable plants.

Third, I use a trowel or shovel to dig holes for transplanting, depending on seedling size. Often I put homemade compost and/or a little granular fertilizer in the hole, and mix this into the soil with a scratcher. Not turning over an entire row of soil when I transplant helps preserve the soil’s organic matter and improves its water retention, which is great for soil microbes and my vegetables.

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

How Dry Was 2015?

Last year Suffolk County experienced its driest growing season in over twenty years. Riverhead received only 21.96 inches of precipitation from March 1 to October 31, 2015, which is 9.27 inches less than the ten-year average rainfall for Riverhead. The last four years in particular have seen a steady decrease in our precipitation, averaging only 26.22 inches in comparison with the previous six year’s average of 34.58 inches. We are surely in a dry spell, but only time will tell what 2016 has in store for us.2015 Seasonal Precipitation for RiverheadSo what did last year’s dry season mean for our landscapes? For one thing, we dragged the hose around more often in an effort to keep plants alive. This was especially true for container plantings, vegetable gardens, newly planted plants, and probably your lawn. Then again, if you left your landscapes to fend for themselves last year, it’s possible you’ll notice more winter damage this spring.

New plantings and transplants, especially of larger trees and shrubs, are probably the hardest to maintain in droughty growing seasons. Keeping the soil moist is very important for establishing strong plants. During the first year of planting, be sure to water trees deeply at least once every week during dry spells; with rainfall, once every two weeks should be fine. Applying a two- to three-inch layer of mulch around them will help keep their roots moist and reduce evaporation from the ground.

During the first autumn after planting trees and shrubs, watering them once every four weeks is recommended. In their second year, these plants should receive supplementary irrigation once every four weeks in the spring, once every three weeks in summer, and once every five weeks in autumn. The key to these waterings is deep and infrequent. A plant should always enter autumn and winter with ample moisture in its system. Research has shown that mid-August through September is the most important time to prepare plants to tolerate winter stress. Once winter arrives and the ground freezes, a plant cannot replace water lost to transpiration by winter sun and wind, making it susceptible to winter injury and die-back.

Most gardeners set out a few containers and pots of plants around their yard each year. These are the plants we need to watch closely during consistently hot, dry days. The trick to watering containers is just like any of your other plants: Water deeply! Let the water run until you see it coming out of the bottom of the pot, which will encourage roots to grow longer, deeper, and ultimately healthier and more resistant to dry days. This year consider creating containers filled with such drought-tolerant species as zinnias, gazanias, salvia, lavender, and dusty miller, or design contemporary containers filled with ornamental grasses or succulents. You could also invest in some self-watering pots that take the guesswork out of when and how much to water, so you don’t have to water your plants every day to keep them hydrated.

Last year after the first flush of spring growth, lawns quickly started gulping for rainfall. Many irrigation systems struggled to keep up with the water demand, and many homeowners without in-ground irrigation weren’t willing to set up sprinklers every day. Typically lawns require an inch of water per week, so professionals often recommend letting lawns without irrigation go dormant over the summer. The majority of lawns on Long Island are made up of cool-season grasses (Kentucky bluegrass, perennial ryegrass and fescues). These grasses look and perform their best in the cooler months of April-June and September-November and prefer to go dormant in the heat of the summer unless they are provided with adequate moisture.

Other factors besides drought last year may affect the health of our plants this year. White oaks were severely defoliated by gypsy moths in 2015. Although oaks can recover and push out a new flush of growth in the same growing season, last year’s drought while they were in recovery may be detrimental to their growth this year. Landscapes damaged by Super Storm Sandy may also be set back by the drought as sufficient water is critical to their long-term recovery. And established trees and shrubs that experienced root disturbances from new driveways, fences, pool installations, or any construction job using heavy equipment and machinery, may struggle as a result of the 2015 drought as well. How your landscape will look this year is pure speculation at this point, but bear these thoughts in mind when monitoring the health of your plants in 2016.

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.

“Waterwise Landscapes,” the 2016 LI Gardening Calendar

Now’s the time to buy the Long Island Gardening Calendar, a perfect gift or stocking stuffer for the passionate gardeners in your life.  The theme for our 2016 calendar is “Waterwise Landscapes,” and it is filled with sustainable gardening tips and beautiful photographs every month. Be inspired by the many landscape and gardening choices we can make to protect Long Island estuaries and water supplies.

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This high-quality calendar features information on drought-tolerant plants, correct use of mulch, drip irrigation, rain barrels, healthy soil, rain gardens, green roofs, and more, including a resource page about local and national organizations that focus on native plants and sustainable horticulture. Purchase calendars at the front desk at CCE Suffolk, 423 Griffing Avenue in Riverhead for $7 each; or use this order form to have them mailed to you for $9 each to cover their cost with postage. Buy your calendars soon while supplies last!

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

Simple Ways to Protect Plants Now from Winter Injury

Weather conditions for the past two years have favored all sorts of winter injury to landscapes; this year may be no different. Droughty summers and autumns followed by long winters filled with wide temperature fluctuations can wreak havoc with plants and soil. But fear not! Here are some simple ways to help your plants come out of this winter unscathed.

Needled and broad-leaved evergreens such as arborvitaes, cherry laurels, and rhododendrons often suffer severe winter discoloration, browning, and even death from several causes. Winter sun (think southern exposure) combined with wind can create excessive transpiration, or foliage loss of water, at the same time as soils are frozen so plant roots can’t replace the lost water. This can be particularly disastrous for late season plantings in October, November, and December if plants aren’t well watered and if roots haven’t had time to grow out of the existing root ball. That’s why September is best for fall planting, not November!

Bright sunny winter days when leaves warm up may trigger cellular activities such as photosynthesis and cellular respiration. This break from dormancy can result in severe plant injury when nighttime temperatures drop abruptly, for example from the 40’s down to the teens in the course of a day or so. These conditions also bleach evergreen foliage, for example on boxwood, when chlorophyll is destroyed in plant tissue and then not rebuilt due to low temperatures. Late pruning in October, which generates new late season growth, is another cause of injury or death when cold temperatures occur. This sort of injury also occurs in May when light frosts settle into low areas during the time of tender new growth.

A piece of burlap posted in front of these inkberry plants will protect them from winter sun and wind. Photo c Alice Raimondo.

A piece of burlap posted in front of these inkberry plants will protect them from winter sun and wind. Photo © Alice Raimondo.

Protecting your evergreens from these sorts of winter injury is easily done. First and foremost, consider where you locate plants. South, southwest, and windy sites may not be the best places for evergreens. For plants in such sensitive conditions and for those that are less winter hardy, consider constructing a burlap barrier on the southern and/or windy side of the plant to shade it from the harsh winter sun and keep temperatures consistent, thereby reducing the injuries described above. Place the screen in front of the plant; don’t wrap it completely with burlap.

Water loss is by far the most important and misunderstood aspect of winter injury. Established plants shouldn’t be over watered in September as this will slow down their hardening off process, but they need to be well watered through October and into November if there isn’t regular, measurable rainfall. This regular watering in the autumn is particularly important for trees and shrubs in the ground for less than three or four years. Anti-desiccant and/or anti-transpirant sprays offer protection that is limited at best, but these can be applied in conjunction with correct watering and sun/wind screens.

Sunscald of thin-barked trees (cherry, maple, linden, and plum) is another common winter injury. Sunscald creates sunken, cracked, or dried areas on the trunk, which are elongate in shape. Young, newly planted trees are particularly sensitive to this damage as their bark is not well developed. Shading tree trunks from the harsh southern winter sun helps keep their living cambium tissue dormant, protecting it from freezing temperatures following a thaw. On young and newly transplanted trees, consider not pruning their lower branches for a season or two to help shade their trunks.

Cold that follows relatively warm temperatures is common on Long Island and often kills or damages less winter-hardy flower buds such as those of Hydrangea macrophylla. This is why many of us haven’t seen flowers on these beloved plants for the past two winters! The big-leafed a.k.a. mophead hydrangea has a bad habit of breaking dormancy as early as late February in sunny locations. Constructing a sun screen similar to that suggested for evergreens may help reduce this sort of cold temperature injury.

Our winters often bring heavy wet snows and ice storms that cause significant injury to plants from extra weight bending and breaking their branches. Protect plants in dangerous locations, such as where snow falls off roofs or where drifting and blowing snows accumulate, by tying or wrapping them to hold them together. If possible, carefully remove heavy, wet snows from plants before the snow freezes solid, encasing the plant in heavy ice.

For those of us with new landscapes, a real concern is frost heaving. Our soils tend to freeze and thaw and then freeze and thaw again, sometimes popping smaller shrubs and perennials right out of the ground. This is a big problem for those fall-sale beauties you may have planted in October or that late season perennial dividing and replanting you did the first week of November when it was 70 degrees. You can protect your plants by insulating the ground around them with mulch. Apply a layer of mulch three-inches thick, being careful to not bury the crowns or stems of the plants. Wait until the ground freezes before applying mulch to keep the ground frozen and discourage rodent activity. Consistent soil temperature will reduce the likelihood of frost heaving.

For more information, read the fact sheet on our website about Winter Injury. Hopefully, some of these simple tips will help your plants survive the winter and thrive come next spring. Putting in a little extra time now will reduce spring cleanup of winter-injured plants that need to be pruned or replaced. There’s still plenty of time to prep plants for the ravages of winter!

Alice Raimondo is Horticulture Consultant for CCE Suffolk. She can be reached at aw242@cornell.edu or 631-727-77850 x335.

Buff Up Your Conservation Buffers

Because Long Island is surrounded by water, responsible residents strive to keep pesticides and fertilizers from polluting our coastal and drinking water resources. And as stewards of our land, we need to preserve as much habitat for wildlife as possible. One way to accomplish both goals is to plant garden or conservation buffers. These small pieces of land with permanent vegetation help control pollution while providing undisturbed habitat for wildlife. Examples of buffers include riparian buffers, small wetlands, shallow water areas, herbaceous and woody windbreaks, contour grass strips, living snow fences, and field borders.

Garden buffers like this one at Cornell Plantations in Ithaca can be used to filter polluted run off from parking lots.

Garden buffers like this one at Cornell Plantations in Ithaca can be used to filter polluted storm-water run off from parking lots. Photo © Robin Simmen

Although you may view them primarily as pleasant landscape features, buffers quietly prevent soil erosion, improve soil and water quality, enhance fish and wildlife habitat, reduce flooding, conserve energy, and ultimately conserve biodiversity. By capturing up to 75 percent of flowing sediment and by enhancing infiltration, buffers trap heavy metals. When properly installed and maintained, they can remove up to 50 percent of pesticides and nutrients from polluting coastal waters!

In addition to providing wildlife habitat (increasing the number and diversity of birds and butterflies) and creating corridors for their movement, buffers are attractive, low-maintenance, sustainable alternatives to traditional turf. Water moves more slowly through shrubs and other buffer plantings as compared to turf, thus reducing your irrigation needs. Conservation buffers can also improve your quality of life by reducing noise from the street and odors from garbage.

An added benefit is that buffers help reduce flooding. They also help stabilize streams, enhance biodiversity by providing micro habitats, and decrease and then stabilize water temperature. Fluctuations in water temperatures and warming can be very deleterious to fish and other aquatic creatures important to the stream food chain.

A shallow water area or a small wetland is a place where water depth is usually less than 2 feet with no more than 10 percent of the entire area being over 4 feet deep. These wet areas may be seasonal in nature, such as vernal pools, so you might be tempted to “dry ‘em out or fill ‘em in,” but DON’T DO IT! Not only is it often illegal to do so, but such spots are of particular importance to certain plants and animal species that depend on transient moisture for parts of their life cycles, e.g. reproduction or nesting.

To learn more about how to construct a conservation buffer on your property or how to evaluate your existing landscape, please join me and Joann Gruttadaurio, Senior Extension Associate Emerita, Cornell University, on October 15, 2015, 9:00 a.m. until noon, at the Suffolk County Farm for a hands-on workshop on how to “Buff Up Your Soil and Garden Buffers.” The cost is $30, and preregistration is required. Click here to download the registration form.

Dr. Tamson Yeh is CCE Suffolk Turf Use and Land Management Specialist. She can be reached at tsy3@cornell.edu or 631-727-7850 x240.

Best Way to Water Your Lawn

Question: I water my lawn every day, but it still looks like it’s drying out and turning brown. What is the correct way to water?

Answer: Usually there’s plenty of rain on Long Island during April, May, and sometimes well into June, but this year we weren’t so lucky. And summer rainfall has not been forthcoming. Most lawns need an inch or so of water each week to stay green, which is approximately how much moisture they lose weekly through evapotranspiration.

I suspect you are running your sprinklers for twenty minutes or so daily. Unfortunately, this means you are wasting lots of water and not helping your lawn. A brief daily shower only moistens the grass blades and doesn’t deliver enough water to the turf roots, which is why your lawn is going into drought stress.

Daily watering resulted in the drought-stressed lawn at the top of this picture. Compare it with the next-door neighbor's healthy lawn at the bottom, which receives one-inch of water just once a week.

Daily watering led to the drought-stressed lawn at the top of this picture. Below it, the next-door neighbor’s green grass receives only an inch of water once a week.

The best way to water your lawn with an inch of water is to soak it just once a week, which may take several hours depending on your water pressure and sprinkler heads. You can determine how long your system takes to supply one inch of water to your lawn by setting several empty tuna cans inside the spray pattern of your sprinklers and watching until they fill up to one inch; or you could buy a few inexpensive plastic rain gauges.

Late summer storms often supply ample amounts of water. As summer winds down, keep track of how much rainfall you get; then adjust your irrigation accordingly. Learn more about correct watering practices by looking at Suffolk County’s Healthy Lawns, Clean Water website, which discusses this in greater detail: http://healthylawns.suffolkcountyny.gov/lawn/watering.htm

Alice Raimondo is Horticulture Consultant for CCE Suffolk. She can be reached at aw242@cornell.edu or 631-727-77850 x335.