SJU Expert Offers Tips on Winterizing Your Garden

As the winter season sets in, the drop in temperature and shorter days spur dormant periods for most plants in your outdoor garden. While varying species of plants and trees react differently to the change in weather, there are a few best practices to ensure that your garden thrives once the spring thaw comes.

Jennifer Walker, head gardener at the Barnes Arboretum at Saint Joseph’s University, tends to over 2,500 varieties of plants and trees every day. She says that there are a lot of mistaken beliefs when it comes to the best ways to winterize your gardens.

“One of the most common misconceptions is that it’s necessary to cut back all perennials before cold weather and frost begin to set in. In reality, it’s often very helpful to both the plant and its environment to leave their stalks and seed heads in tact through the winter, unless the individual plant happens to have some type of disease,” explains Walker. “The seeds make great food for birds, and birds keep bugs away.”

Walker also says cutting back plants should be kept to a minimum. “Tidy up as much as you have to but leave as much as you can for protection and feeding,” she explains. The late-fall season is also a good time to divide or transplant any of your perennials that bloom in early spring or the summer, before your soil hardens in the winter.

“With the freeze and thaw cycle that comes along with the fall and winter seasons — when we have warm days then cold then warm — oftentimes this can cause the roots of small plants to come up in the soil and dry out,” says Walker. “The best way to combat this is to cover the soil, which can be done with a protective mulch often sold at gardening and home improvement stores.” Gardeners can also make their own mulch using shredded leaves and compost.

But before covering your soil, Walker recommends planting any new woody trees and shrubs, as their roots will keep growing during the winter. This gives them time to develop a good base of roots so that they won’t dry out as easily during the summer months. “Tree and shrub roots grow in the wintertime, even when the ground is frozen,” she says.

However, Walker points out that the colder weather isn’t the only concern for your plants this winter. Insects, like the invasive spotted lanternfly that’s been taking over Philadelphia and the Northeastern U.S. are laying their egg sacs now to hatch in late spring. “They typically go after horticultural crops, like grapes or apples, but they can create a nuisance on home landscapes” by way of the lantern fly honeydew – a sugary excrement that can attract wasps and bees and be unsightly, Walker explains. You can search for and destroy for egg sacs in your own garden, but know that eliminating this pest is not possible at this point in time.

For anyone interested in learning more about how to take care of their plants before the first winter cold snap comes, Walker recommends visiting the Barnes Arboretum. The Arboretum offers volunteer hours, classes, workshops, and even a horticulture certificate program , so there is something that fits every skill level. Or, just stop in and ask Walker yourself. “I really enjoy pop quizzes. I loved being asked questions,” she says.