A warm day in March can inspire a kind of madness in gardeners. It can cause them to burst out the door, desperate after months cooped up by cold and snow, and start work way too soon.
“Be careful what you do right now,” said Sharon Yiesla, plant knowledge specialist at the Morton Arboretum in Lisle. “There are things it’s just too early for.”
Here are some do’s and don’ts for early spring gardening:
Do get rid of tree wrap. If you wrapped the trunk of a young tree to protect it from animals over the winter, unwrap it now. “Leaving tree wrap on too long can trap moisture and encourage disease,” Yiesla said.
Don’t walk on or dig in wet soil. “That can compact the soil, which smothers plant roots,” Yiesla said. “Compacted soil is a very difficult condition to correct.” Even as soil thaws at the surface, a hidden layer of impermeable ice often remains below, trapping water like a soup bowl. Wait until the soil has thawed all the way down and water is draining freely through it before you start digging or even walking on any part of the yard, including the lawn.
Do force branches of flowering shrubs. Cut branches of forsythia, flowering quince or other spring bloomers and stand them in a vase of warm water to encourage them to bloom indoors. “Just make sure you prune carefully and leave the overall shape of the shrub looking good,” Yiesla said.
Don’t prune trees. If you prune certain trees such as maples, elms and birches now that their sap is flowing, the pruning cuts will “bleed” with sap that is not only unsightly but can attract diseases and insects. Other species, such as oaks, also will be vulnerable to infectious diseases through pruning wounds. “The best time to prune trees is in the winter, when the trees are dormant, the leaves are gone and diseases don’t spread easily,” Yiesla said.
Do cut back perennials and grasses. Cut last year’s stalks on ornamental grasses back to a couple of inches above the ground before new growth starts. Remove any dried stalks of perennials that are still standing. Do this while the soil is still frozen or after it has thoroughly drained to avoid walking on wet soil.
Don’t clean up too much. Fallen leaves on garden beds protect plants from hard freezes, which are still common in March and early April. Even later in the season, keep some leaves on the ground as mulch, protecting plants’ roots and enriching the soil.
Do prune shrub roses. There’s no need to cut back every stem, as you would with a hybrid tea rose. Instead, prune out any stem or part of a stem that has died over the winter, and prune the shrub as needed for overall size and shape.
Don’t mow, fertilize or treat the lawn. Let grass grow for a few weeks before you work on it. Wait until mid- to late April to apply pre-emergent herbicides that aim to prevent crabgrass.
Do plan your planting. If you intend to add trees, shrubs or perennials this year, now is the time to figure out the species or varieties that are best for your site and locate a source. “You’ll have a tree for a long time,” Yiesla said. “It’s definitely worthwhile to invest some time and effort to choose the right one.”
Choose your tasks carefully and you can relieve your cabin fever without harming your plants.
For tree and plant advice, contact the Arboretum’s Plant Clinic (630-719-2424 or [email protected]).
Beth Botts is a staff writer at the Morton Arboretum in Lisle (www.mortonarb.org).
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