Horticulture experts share secrets for choosing right trees for your landscape

February 13, 2013 under CANR News, Cooperative Extension

Photos of Brandywine Creek State Park and the Brandywine River.At the end of January, the Delaware Center for Horticulture (DCH) offered a workshop on choosing the right trees for your landscape. This past Thursday, University of Delaware Master Gardeners presented a session on spring planting. On Feb. 20, the Delaware Nature Society will offer a similar program.

While it might seem like these gung-ho gardeners are rushing spring — after all, it’s only mid-February — Delaware’s plant sale season is already underway.

DCH kicked things off with its bare root tree sale, featuring 10 varieties of low-maintenance, easy-to-grow trees. Orders will be accepted through Feb. 15, with tree pick-up March 20-21. Two other major plant sales – at the UD Botanic Gardens and Delaware Nature Society – take place in April.

“Now’s the time to start making decisions about what to plant this spring,” says Carrie Murphy, a horticulture agent for New Castle County Cooperative Extension. “It’s important to research your options and choose carefully, especially for trees, such a prominent part of the landscape.”

For starters, don’t fall in love with a particular species and overlook the fact that it may not be right for a site, advises DCH tree program manager Patrice Sheehan, who led the recent tree workshop. For example, the American hophornbeam is one of her all-time favorite trees because of its exfoliating bark and hop-shaped seed that’s gobbled up by many songbirds. But when a workshop participant asked what to plant on a berm, Sheehan never would have thought to suggest this native species.

“American hophornbeams prefer moist soils. A berm gets lots of wind. Couple that with the slope of the site, and the end result is soil that dries out quickly,” she says.

Instead, Sheehan told the gardener to consider the Eastern red cedar. This native can thrive in windy places like berms where other trees can’t. Not only does it put up with high winds but it can tolerate dry and alkaline soils and it lives a long time.

Just like some little puppies grow up to be huge dogs, some little saplings grow up to be humongous trees. Think about whether the tree at its mature size will work well where you want to plant it. Don’t place large trees near overhead utility wires or too close to the house.

Consider not only the mature height of the tree but its canopy spread – how wide it will grow. Oaks have wide canopies, as well as many species of maples. These are great choices if you’re looking for extensive, even shading; not so great if you plant one too close to your property line and branches extend over the neighbor’s fence.

Don’t forget to provide enough room for the tree’s roots – don’t, for example, plant a large tree in a narrow strip of land between a sidewalk and street. “Plan on root growth extending well beyond the spread of the canopy at maturity,” notes Murphy.

Other factors to consider when choosing a tree are its form and shape; soil, sun and moisture requirements; whether it’s coniferous or deciduous; and its growth rate, which usually correlates with the life span. Fast growers have softer wood and usually don’t live very long. Slow growers are hardwoods that tend to live longer. Many gardeners also like to plant species that provide food or shelter for wildlife.

One of Sheehan’s favorite large trees is the Princeton elm, a majestic native with a vase shape and yellow fall color. Although it’s beautiful on the outside, it’s tough on the inside – it’s highly tolerant of pollution and other stressors.

Medium-sized trees that she likes include the black gum, also known as black tupelo, for its reddish fall foliage. For winter interest, her hands-down favorite is the bald cypress, with its peeling, copper-brown bark and tiered, upward-facing branches.

If you see a tree you like while walking or driving in Wilmington but don’t know what you’re looking at, check out the Street Tree Inventory maintained by DCH and the city of Wilmington. It provides a complete inventory of Wilmington’s street trees.

For more information

Order bare-root trees from DCH by Feb. 15. For more information, go to the organization’s website or call 658-6262.

Learn about designing your own landscape at “Dig In at DEEC” Feb. 20 at the DuPont Environmental Education Center in Wilmington. Call 239-2334 to register.

DCH will hold a free “How to Plant Your Bare-Root Tree” workshop on March 20. To register, call 658-6262.

Article by Margo McDonough

Photo by Evan Krape

This article can also be viewed on UDaily.

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Trees can help cities better prepare for severe weather events

November 21, 2012 under CANR News, Cooperative Extension

In the aftermath of Hurricane Sandy, many cities are taking a look at how they can better prepare for severe weather events. A low-tech – but effective – solution is to plant trees, says Sue Barton, ornamental horticultural specialist for the University of Delaware.

“A single mature tree can intercept several thousands of gallons of stormwater. Plant more trees in the right places and you can mitigate the impact of storm events,” says Barton.

She points to the research of David Nowak, a forester at the U.S. Department of Agriculture’s Northern Research Station in Syracuse, N.Y., who has analyzed the role that “urban forests” play in controlling runoff and flooding, reducing the costs of stormwater management facilities, and decreasing water pollution.

An “urban forest” doesn’t necessarily mean a tree-filled area the size of Central Park. Instead, researchers like Nowak look at the overall tree coverage in a community. The average urban tree canopy in the U.S. is 23 percent. But the tree canopy in the New Castle County metro area is estimated to be just 19 percent, and the city of Wilmington’s tree canopy is 16 percent.

“Philadelphia and Wilmington have experienced water overflow situations after decent-sized rains, not just storm events like Hurricane Sandy,” says Barton, a Cooperative Extension specialist and associate professor in the Department of Plant and Soil Sciences. “The stormwater management systems in these cities were engineered many years ago and they can’t handle the water flow after a big rain – which means raw sewage and other organic material bypasses the treatment plants and go directly into streams.”

Fixing antiquated stormwater systems isn’t cheap. “One of Nowak’s greatest contributions may be his research into the economic benefits of trees,” says Barton. “He came up with a way to put a dollar cost on how much trees can save a community. He looks at the cost of trees and tree maintenance relative to the costs of updating aging stormwater systems.”

In Wilmington, the Delaware Center for Horticulture (DCH) has been a driving force behind stormwater mitigation efforts that include planting trees and shrubs, establishing rain gardens and installing underground holding tanks. All three of these elements were included in a stormwater project at the Trolley Square Acme that was completed in June 2011.

The 9,000-square-foot project filters, slows and absorbs rain that falls on the roof of the Acme and its 1.42 acre parking lot. Comprised of 19 shade trees, more than 2,800 shrubs and smaller perennial plants, a rain garden, and underground holding tanks, the project captures an estimated 70 percent of the site’s annual rainfall, providing relief to the city’s combined stormwater and sewer system.

Gary Schwetz is a senior project analyst at DCH and was instrumental in the development and execution of the Acme project. His advice to those who want to use trees to intercept stormwater: “Think big.”

Schwetz doesn’t mean you need to plan a big project – like the 2,819 or so living things planted at the Acme — but that you need to include big trees.

“Large trees are better at absorbing rainwater and mitigating air pollution,” says Schwetz.  “A 20-foot tree will have eight times the environmental benefits of a 10-foot tree.”

Of course, it can be tough to grow a big tree in the narrow space between a city sidewalk and the street, or in a city backyard. It can even be tough for big trees to do well in public spaces like Rodney Square, which little by little has seen its grassy area reduced and covered by pavers and other impervious surfaces.

Schwetz and fellow DCH staffers worked on an innovative landscape project that will help big trees flourish at Rodney Square. Other partners were the city of Wilmington and the Delaware Department of Transportation.

What makes the project different, says Schwetz, is the use of a new structural cell technology as the planting medium. These milk-crate-like structural cells can support sidewalks and hold a high volume of good quality soil, creating conditions in which large trees should be able to thrive.

Rodney Square isn’t the only place the city of Wilmington has been planting trees lately. Some 250 trees were planted by the city in the last year and a half. And, one year ago, the city hired Mandy Tolino has its first-ever urban forest administrator.

“Trees and the green infrastructure improve water quality by helping slow water down during a storm, as well as by reducing erosion,” notes Tolino.

Recently, she has been involved in a pilot tree trench installation at Brown Burton Winchester Park, at 23rd and Locust streets. On the surface, this tree trench looks like an ordinary row of trees. But underground, the trench is lined with a permeable fabric and filled with gravel. During a rainstorm, water flows through a storm drain to the trench, where it’s stored in the empty spaces between the stones before slowly infiltrating into the soil below.

There will be a public dedication of the Rodney Square landscape project on Nov. 27 at noon. For more information, call the Delaware Center for Horticulture at 658-6262.

Article by Margo McDonough

Photo by Danielle Quigley

This article can also be viewed on UDaily.

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Baked kale chips are Delaware’s hottest new snack food

April 3, 2012 under CANR News, Cooperative Extension

Put aside the sour cream and onion chips. Abandon those messy, orange cheese curls. Toss away the nachos topped with gloppy processed cheese. Make way for Delaware’s hottest new snack food – baked kale chips.

If the Delaware Urban Farm Coalition has its way, every Delawarean will soon be munching on this snack sensation. “Kale chips have the crunch and flavor that people love but, unlike most snacks, they’re nutritious, too. Kale is rich in vitamins, minerals and anti-oxidants,” says Carrie Murphy, a University of Delaware Cooperative Extensive horticulture agent and the interim chair of the Delaware Urban Farm Coalition.

“The Urban Farm Coalition wants to generate excitement about growing local foods and eating local foods. Coalition member Tara Tracy hit on the idea of creating a buzz about kale chips,” says Murphy.

“When we posted a kale chip recipe on the coalition’s Facebook page, we had positive feedback from everyone from mom bloggers to health specialists. The recipe has caught everyone’s attention,” she says.

Kale chips are easy to make (see recipe below) and kale – which is related to cauliflower and broccoli – is easy to grow. Plus, kale is readily available in most Delaware supermarkets and, later in the season, at farmers markets and farm stands.

However, for many residents of Wilmington, it’s not easy to obtain kale and other fresh produce. Large swaths of the city have been termed “food deserts” by the U.S. Department of Agriculture because they lack convenient access to a supermarket and limited or no opportunities for residents to grow their own food.

The Delaware Urban Farm Coalition is doing a lot to change that. Since its inception in 2008, the coalition has worked to expand community gardens and on other ways to improve access to healthy foods in the city. In addition, it helps to teach local residents about healthy eating (including how to make kale chips) through programs run by coalition members such as the Food Bank of Delaware.

The coalition is made up of almost a dozen organizations. Key partners are UD Cooperative Extension, Delaware Center for Horticulture and Delaware Department of Agriculture. The coalition’s presence can be felt in dozens of neighborhoods, from a nascent garden in Edgemoor to the thriving “West Side Grows” garden in the Cool Springs area of the city. But the cornerstone of the coalition’s efforts is the 12th and Brandywine Urban Farm, which had its first harvest in 2010.

“What makes the urban farm different from a community garden is its focus on production agriculture,” explains Tracy, who is urban agriculture manager for the Delaware Center for Horticulture. “Our 1,600-square-foot urban farm grows fruits and vegetables – including kale – that are sold at an on-site farmer’s market. In addition, we operate a 1,200-squre-foot community garden at this site, where residents can rent plots for a small fee. And, yes, we do grow kale in the urban farm and sell it at the farmers market.”

Delaware Center for Horticulture staffers and volunteers do the bulk of the planting, tending and harvesting at the urban farm. But a farm apprentice will be hired soon to assist with farm chores and engage more community members in the project.

Tracy is quick to note that East Side residents don’t need to pull weeds to help out. “A working mother who is too busy to volunteer is still helping the farm – and her family – when she purchases produce at our weekly farmer’s market,” she says.

The Delaware Urban Farm Coalition is now growing beyond its city of Wilmington roots.

“I’ve had phone calls from individuals and organizations throughout Delaware who want to get involved,” says Murphy. “The coalition has really become a statewide effort.”

If you want to learn more about the Delaware Urban Farm Coalition, contact Murphy at cjmurphy@udel.edu or Tracy at ttracy@thedch.org.

If you want to buy kale and other produce from the coalition’s farmer’s market, its opening day is May 7. Located at 12th and Brandywine streets, the market is open every Monday in season from 4-7 p.m.

If you want to grow kale yourself, now’s the time to plant this cool-season crop, says Murphy. Seedlings are available at garden stores throughout the state. Plant now and you’ll have fresh kale by early June.

And if you want to make your own kale chips, here’s what to do:

BAKED KALE CHIPS

1 bunch kale (4-5 cups)

1 TBS olive oil (olive oil spray works especially well)

1 TSP sea salt or seasoned salt

1 TSP vinegar

1. Preheat oven to 325 degrees. Line a non-insulated cookie sheet with parchment paper.

2. With a knife or kitchen shears, carefully remove the leaves from the thick stems and tear into bite size pieces. Wash and thoroughly dry kale pieces with a salad spinner. Drizzle chips with olive oil or spray with olive oil. Sprinkle with vinegar and seasonings.

3. Bake until the edges are brown, anywhere from 10 to 20 minutes. Gently stir leaves halfway through baking.

Try different seasoning combinations, suggest Murphy and Tracy. Teens may prefer a spiced-up version; cheese lovers may want to sprinkle parmesan cheese on top before baking.

Article by Margo McDonough

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March 3: Community gardens

February 6, 2012 under CANR News, Cooperative Extension, Events

Are you interested in starting or maintaining a community or school garden? Experts from the University of Delaware, Delaware Department of Agriculture, Delaware Center for Horticulture and Healthy Foods for Healthy Kids will hold an information session on Saturday, March 3, from 9 a.m. to noon, for interested educators, community members and gardeners.

The session will highlight successful, local garden projects and provide information to help participants in their community or school garden, whether that’s a vegetable garden, nature trail or butterfly garden.

“A workshop like this is long overdue,” says Carrie Murphy, educator for ornamental horticulture withUD Cooperative Extension.  “For the last two to three years, we’ve seen a major influx of phone calls, emails and in-person questions about starting and maintaining school and community gardens. Through the workshop, we hope to not only give people the resources that they need, but also give them a space to network with each other.”

In addition to expert presentations, Master Gardeners will have displays on a variety of topics including water conservation, soil testing, attracting pollinators and more.

The information session will be held in 132 Townsend Hall on the University of Delaware campus.  Townsend Hall is located at 531 South College Avenue in Newark.

To register, call or email Murphy at 302-831-2506 or cjmurphy@udel.edu.  Preregistration is required, but the workshop fee of $5 will be collected at the door.  Participants are asked to bring their own mugs for coffee.

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UD horticulturalists see understated attractions of winter landscape

January 26, 2012 under CANR News, Cooperative Extension

The lyrics of “California Dreamin'” by John and Michelle Phillips are well known and appropriate for the season: “All the leaves are brown, and the sky is grey, California Dreamin’ on such a winter’s day.”

Although many yearn to flee the First State during the long slog of winter, not everyone is dreaming of California. For every Delaware gardener poring over seed catalogs and wishing for spring, there’s another gardener like John Frett who’s outside every day enjoying the landscape, regardless of the weather.

Frett, the director of the University of Delaware Botanic Gardens (UDBG), loves winter and spends time in his yard or the botanic gardens every day, all year long.

“I grew up in Chicago and lived in Maine for three years,” says Frett. “Delaware doesn’t know what cold weather is.”

Beyond a hearty constitution for the cold, Frett has an appreciation for the understated attractions of the winter landscape.

“The structure of the trees, shrubs and woody plants are more evident in winter when there are fewer things competing for your attention,” says Frett.

At the 15-acre UD Botanic Gardens, the leaves are long gone (evergreens excepted) so it’s easy to see that trees come in all shapes and sizes. There are columnar, round, conical, broad-spreading, upright-spreading, weeping and elliptical trees in the gardens. And a wide range of texture is now revealed, from the peel-away bark of the paperbark maple to the ridged and furrowed bark of the tulip poplar.

But it’s not just a lack of competing attractions that makes the winter landscape visually arresting for Andrew Olson, public landscape manager for the Delaware Center for Horticulture. He points out that the weaker winter sun casts a different light on things.

“The lower angle of the sun in the winter really highlights grasses and garden structures,” says Olson. “Even the silhouettes of trees ‘pop’ in the waning afternoon light. A garden or natural landscape that may seem brown and bleak can be spectacular as the sun rises or sets.”

Carrie Murphy, New Castle County horticulture agent for UD Cooperative Extension, notes that a landscape’s backbone is completely revealed in winter. “Everything is completely naked and the landscape’s overall shape and structure becomes a focal point.”

“I also appreciate how sounds move through a winter landscape — everything is much more audible — the whipping winds, rustling leaves and movements of wildlife,” she says.

Eileen Boyle looks for the small details in the landscape. “While the perennials sleep off the winter and the bulbs wait their turn, I am enjoying the daily show of the ferns, mosses and other little plants that are last to go dormant,” says Boyle, a horticulturalist at Hagley Museum and Gardens.

Fellow Hagley horticulturalist Renee Huber says that she appreciates the structure of beech and sycamore trees in winter.

“I always enjoy the sycamore trees against the Brandywine this time of year; they’re like gentle giants with white and gray blotched bark,” says Huber.

Sue Barton, UD Cooperative Extension specialist for ornamental horticulture, likes the sycamore in winter, too. Other favorites include river birch, winterberry holly and the Emerald Sentinel variety of Eastern red cedar, which has vivid blue fruit.

Bob Lyons, director of UD’s Longwood Graduate Program in Public Horticulture, admits that he doesn’t much like winter. However, he does appreciate the architecture of trees now, especially when they’re outlined by a wet snow.  He particularly enjoys sweet gum, tulip poplar and deciduous hollies.

If the winter landscape looks enticing — that is, until you read the forecast and hear the winds howl — Olson has just two words of advice: “get outside.”

“Put on some layers and get out there,” he says. “You will be so glad you did.”

Here are some of the things to see in the late-January landscape:

• At the Delaware Center for Horticulture’s gardens, which are free and open to the public, a bloodtwig dogwood (Cornus sanguinea ‘Winter Flame’) gets lots of attention this time of year because of its intensely colored red and orange stems. Also look for the black pussy willow, which is beginning to display purplish black catkins. The Kentucky coffee tree, paperbark maple and river birch also look great this time of year, says Olson.

• Evergreen fans will want to check out the UD Botanic Gardens, which has a large collection of both conifer and broad-leaf evergreens. Native species include the loblolly pine and American holly. And you’ll find many other hollies — the UDBG features 50-plus varieties and is a test arboretum for the American Holly Society.

• At Hagley Museum and Gardens, snowdrops are in bloom in front of the Hagley residences and skunk cabbage is blooming in the woods and by the river. Boyle notes that the bright orange rose hips on old-fashioned antique variety roses provide perching and food for local birds.  Hagley arborist Richard Pratt loves Hagley’s osage orange in wintertime. “It stands like a large bronze sculpture with its deeply furrowed copper-colored bark on its majestic trunk and its crown spreading high and wide into the sky,” says Pratt.

Article by Margo McDonough

Photo by Danielle Quigley

This article can also be viewed on UDaily

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Therapeutic community garden offers natural relief

December 6, 2010 under CANR News, Cooperative Extension

When we’re having a bad day, many of us intuitively seek relief in nature, whether that means a hike in the woods, quick stroll through the park, or merely adding a green plant to an otherwise sterile work cubicle.

Scientists would say we’re doing the right thing. A slew of studies indicate that interaction with nature reduces stress and anger, improves cognitive performance and increases one’s sense of connection to the world.

For those who are experiencing more than just a bad day and suffer from depression or other mental illnesses, the benefits of nature may be even greater.

Recently, Cooperative Extension and the Longwood Graduate Program in Public Horticulture at the University of Delaware began helping clients of the state’s Department of Health and Social Services (DHSS) enjoy the uplifting benefits of nature. They developed plans for a therapeutic and community garden on DHSS’s Herman M. Holloway, Sr., Campus in New Castle.

Partners in the project include UD’s Center for Disabilities Studies, Delaware Department of Agriculture, Delaware Center for Horticulture and the National Alliance on Mental Illness.

The Longwood Fellows took on the garden design as their annual professional outreach project. But even before a single design was sketched, Extension and Department of Agriculture professionals got to work on an education program for the clients.

“We offered workshops to develop interest in gardening,” says Carrie Murphy, horticulture agent for New Castle County Extension. “There was already a lot of interest; in fact, the clients wanted to begin growing vegetables immediately. So we designed and planted a 20- by 30-foot vegetable garden at the Holloway campus this past summer and showed the clients how to prep the soil, plant, weed, compost and harvest.”

First-year crops included popcorn, pumpkins, sweet corn and sunflowers.

Thursday has become “Garden Day” when Extension and Department of Agriculture staff and Master Gardeners offer structured activities at the Holloway campus.

One week, Master Gardener Hetty Francke gave a composting demonstration, another week entomologist Brian Kunkel discussed how to tackle garden pests. Even now, as winter draws near, Garden Day continues. One recent Thursday, Department of Agriculture entomologist Heather Disque gave a talk on where bees spend the cold-weather months.

Holloway clients and employees provided input into the therapeutic garden’s design.

The Longwood Fellows organized a design charrette, a brainstorming session with Holloway clients and other stakeholders, as well as representatives from the professional horticulture community. The fellows also held informal focus groups on the Holloway campus.

One thing they quickly discovered, says Longwood Fellow Rebecca Pineo, was the clients’ wish to memorialize individuals buried in a nearby potter’s field. So the garden design maintains open sight lines to this field from the main garden area. In addition, the clients will be creating garden art in on-site ceramic studios; some of these works may be utilized for memorial purposes.

Before hitting the drawing board, the fellows also researched existing therapeutic gardens. A few traveled to the Buehler Enabling Garden at the Chicago Botanic Garden, which is considered a model in engaging people of all abilities in gardening. And all 10 fellows visited Philadelphia’s Friends Hospital, which has had a therapeutic garden on site since 1817.

The final design that the Longwood Fellows created splits the one-acre garden into quadrants that feature raised beds and green walls. One quadrant will have a slate wall for chalk art, an idea suggested by clients. The design also includes a woodland walk, an avenue of mixed-species trees and two shaded plazas, which can be used for everything from picnic lunches to workshops. Smaller, semi-enclosed seating nooks appear perfect for contemplation.

Sustainable landscaping practices were incorporated into every facet of the garden design, says the Department of Agriculture’s Faith Kuehn, a project leader. The garden design includes native plants whenever possible, uses some recycled materials for garden hardscapes, designates rain collection in barrels and by other means, incorporates a composting station and utilizes solar and other green technologies.

“This project helped me learn about working with a lot of different people,” says Pineo. “We had multiple partners and each partner brought different work styles, perspectives and creativity. It was challenging but it was a good lesson in the strength you can get from partnerships.”

“It’s been a win-win situation for all involved,” says Bob Lyons, director of the Longwood Graduate Program. “The therapeutic and community garden has great potential to improve the experience of the clients of the Holloway campus; it also served to grow the fellows’ experience in coordinating focus groups, design charrettes and conceptual designs.”

Although the educational piece of the project is well underway, the therapeutic garden is still just a design on paper. The project team is seeking donations and grants.

To learn more about the garden, contact Murphy at [cjmurphy@udel.edu] or (302) 831-COOP or Kuehn at [Faith.Kuehn@state.de.us] or (302) 698-4587.

Article by Margo McDonough

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