Winterizing Your Garden

Know your plant hardiness zone and your frost date

The USDA Plant Hardiness Zone Map is the standard by which gardeners and growers can determine which plants are most likely to thrive at a location. The map is based on the average annual minimum winter temperature, divided into 10-degree F zones.

Gasper’s Nursery is in zone 7A. Winter temperatures in our area can potentially fall to -5° F. If you live north or south of us, you can find your zone on the USDA Plant Hardiness Zone Map.   

It is helpful to know when there is a possibility of frost in your area. At Gasper’s, we know that after October 15th, there is a high possibility of a killing frost. A killing frost occurs when temperatures dip below freezing long enough to kill or damage tender annuals and plants.  

Protect or dig tender plants and bulbs

Before your frost date, it is an excellent idea to protect, move, or dig tender plants & bulbs that you are hoping to save. Protect tender plants that can remain outdoors, such as figs, with burlap and shredded leaves. Non-hardy bulbs, such as cannas and dahlias, can be dug and stored in a cool, dry space such as a cellar. Tropical houseplants that have been summering outside on a porch or patio should be given a good drenching shower from your garden hose to remove insect and pest tag-alongs and then moved back inside. Have extra space in a south-facing window? Some flowering annuals such as begonias and geraniums can be brought in and enjoyed through the winter months.

Remove annuals and trim back perennials

Remove and discard tender annuals from the garden before frost to avoid the black mush that will happen if they freeze. Trim back perennials. Dispose of any diseased or pest-infested plant material. Compost any other trimmings. Try to leave items that might provide visual interest or food for wildlife. Ornamental grasses or perennials with interesting seed heads such as black-eyed Susans, add interest to the winter garden.

Remove weeds and other invasive species

Do not let weeds or other invasive hang out in your garden all winter long. Physically removing visible weeds during your garden winterization gives you a head start on keeping weeds under control in the spring and reduces your garden’s exposure to weed seeds. Some plants, such as dandelions germinate in the summer, overwinter in your yard and flower next spring. Removal in late fall helps to disrupt its growing cycle. Dispose of all weed material offsite and not in your home compost pile because they will not get hot enough to sterilize weed seeds. 

Trim with caution

Pruning often stimulates new growth, and if that new growth does not have time to harden off before colder temperatures, it can be harmed or damaged. Avoid pruning evergreens in the late fall and winter, except to remove damaged or diseased branches. If you prune flowering shrubs at this time, you may risk cutting off dormant buds and flowers next year. Pruning some woodier perennials such as sage and lavender late in the year may even hinder winter survival. Typically, early spring or just after flowering is the best time to prune most shrubs.

Wilt-Pruf your broad-leafed evergreens

Your plants need water even during their dormancy. Usually, water is available during winter storms and thaws. Broad-leaf evergreens such as laurels, hollies, boxwood, and rhododendrons are particularly vulnerable to drying, harsh winter winds, especially when grounds are frozen. Winter damage can result in dry, brown leaves the following spring. Protection is particularly important for new plantings since their root systems are not yet fully developed. Spraying these vulnerable plants with an anti-transpirant such as Wilt-Pruf, can provide some protection against this type of winter damage. 

Wilt-Pruf is a clear coating sprayed on leaves to help reduce moisture loss under times of water stress, and we have found it effective in reducing winter burn. We recommend spraying your plants 2 to 3 times in late fall and early winter.

Heavily mulch newly planted material

We recommend putting a few extra inches of mulch around the root balls of certain new plants. Crape myrtles, cherry laurels, schip laurels, and hollies all benefit from the extra mulch. Just remember to rake away the extra mulch in the spring.

Cover fountains and outdoor furnishings

Fountains should be drained and covered with a tarp or waterproof fountain cover. Water that is allowed to sit in fountain bowls increases the risk of cracking or spalling. Whenever possible, remove the pump and store it in a dry place such as a garage.

Outdoor furniture should also be covered. There are many covers available at the Gasper Garden Center. If possible, store cushions separately in a shed, basement or garage. On more than one occasion, we have been told of nesting animals such as squirrels and chipmunks, finding covered cushions as the perfect place to build winter nests.  

Make sure frost-resistant containers have good drainage

Most of the containers we sell at Gasper are frost-resistant, not frost-proof. The best way to help your pots make it through the winter is to make sure that they have excellent drainage. It is crucial to make sure that the drainage hole of containers that you are going to leave outdoors is clear of debris. Products such as pot feet or pot risers can help raise the pot off the ground, giving a few inches of clearance and better drainage.

Shred and stockpile fall leaves

Fallen leaves can create great natural compost, mulch, and fertilizer for your lawn and planting beds. Thick piles of whole leaves can smother the lawn and, under some situations, can both inhibit water and air to getting to your plant’s roots. It is important to shred your leaves before using them. There are many leaf shredding tools on the market, but the most straightforward method might be running over them with your bagging lawnmower. Shredded leaf composts, also called leaf molds, are excellent natural mulches and are easy to make with a bit of time and patience.