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Gardens must be prepped for cold

Butler Eagle - 9/17/2013
Paula Grubs - Eagle Staff Writer

Peg Campbell trims daisies and prepares them for winter Friday at the Cranberry Municipal Building garden. Campbell is a Penn State master gardener. BOB FRITZ/SPECIAL TO THE EAGLE

CRANBERRY TWP — Now is the time to consider your plants’ long winter sleep or journey’s end. That’s the word from Penn State master gardener Peg Campbell, a longtime member of the Southern Butler County Garden Club. Regarding perennials, or plants that return each spring, some should be cut down and some should be left standing in anticipation of the late fall and winter weather. She said as soon as the frost kills the foliage or flowers on perennials, they should be cut down to within a few inches of the ground. Campbell warns if vegetation that grows on top of a plant’s crown is allowed to rot after being exposed to frost, it could cause a major problem for the plant in seasons to come.

Campbell also recommends covering the shortened plants with an inch or so of grass clippings, mulch or other organic matter to insulate the plant during the harsh winter months. She said if spring growth has begun to appear under the leaves of perennials in the fall, the plants should be cut right above the new growth. Examples of plants that should by cut back after the first frost are peonies, flox, hostas and perennial chrysanthemums. “They’ll come back next year,” she said. Cambell said plants in the cone flower family, such as liatris, echinacea and autumn sedum, should be left alone in the autumn because their seeds feed birds. Plants in the ornamental grass family should be left alone in the fall, and old growth should be cut away in the spring, when new growth appears, Campbell said.

Some herbs, Campbell explained, successfully make it through winter on their own and some must be covered with mulch or grass clippings to survive the cold weather. One important fall chore, Campbell said, is weeding flower gardens. Some varieties of weeds will develop seed heads that will winter over in the garden and produce more weeds for the next growing season. “You want to have as few weeds as possible,” she said. Following the cleanup, gardeners should place an inch or so of chopped leaves on top of the bed to supply nutrients to the soil and protect any plants underneath. But Campbell advises waiting until late in the fall when moles and other burrowing wildlife have already found their homes. If covered too early, the animals will hibernate in the ground covering.

Regarding annual flowers, such as impatiens, begonias, petunias and nasturtium, Campbell said they should be removed from the bed as soon as the first frost begins to whither them. Any weeds should also be removed at that time. While gardeners are performing prewinter duties in their gardens, Campbell said, the successful ones also will assess the growing season, how each species performed, which annuals should be divided, whether to move plants around and other factors. “A lot of gardeners at this point will be walking through their landscaping taking notes,” Campbell said. She also cautioned against fertilizing soil when the growing season is coming to a close. “That will produce green leaves in the fall that will be killed by the frost,” Campbell said.

There is one plant, the hellebore, that stays green all winter in the northern climate and then produces blooms in the spring, Campbell said. It must be planted in the shade. When the temperatures drop and the winter coats come out, Campbell said it is actually better to have a blanket of snow on perennial beds than cold, windy, precipitation-free days and nights. “The snow is an insulator for the plant,” she said. Campbell said she leaves her beds bare in the late fall and winter, but noted that hydrangea blooms will hang on for most of the winter. “They will add some interest to the landscape, even though they turn brown,” she said. Once the ground thaws and the birds begin to return in the spring, Campbell said gardeners should not be fooled by an unusually warm April and start their gardening. “May 15 is the average date for the last frost.” As a volunteer from the garden club, Campbell maintains the gardens at the Sample Schoolhouse at the Cranberry Township Municipal Center.