Native Delaware: Tree time
Horticulture experts share secrets for choosing right trees for your landscape
10:16 a.m., Feb. 12, 2013--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.
A taste of psychology
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