Q: My garden containers and window boxes were showpieces this summer. The beautiful annuals planted in the pots added color, texture and lots of interest to the front of the house as well as the patio. What can I do to keep these containers great looking during the coming winter?

A: It’s true that empty window boxes and garden planters add to the dreariness of the winter season. With the correct potting material, winter-hardy plants along with a few sprigs of berries and evergreen branches, container gardens can change winter from the bleakest season to one that rivals the warm-weather one.

Consider weatherproof pots that will withstand freezing temperatures. Water expands when it freezes thus endangering terra-cotta, ceramic and concrete pots that crack in a harsh freeze. Tip these planters on their sides during winter so the freezing soil can expand toward the open end. Metal, plastic and fiberglass containers are safer choices.

Provide good drainage by covering the drainage hole with landscape fabric or a piece of window screen; then add a little gravel before filling with potting soil. If the plants will remain in the container through summer, mix in compost with the loosened potting soil to encourage root growth. Add 3 or 4 inches of mulch to insulate and protect the roots from drying out.

Container plants will experience colder temperatures than those planted in the ground. Select slow-growing or dwarf evergreens that grow in two zones lower than your hardiness zone.

In this area, dwarf evergreens, holly, ivy and boxwoods are a few suggestions. Add color with kale, chokeberry and red or white twigs as accent pieces. Keep evergreens and cut boughs looking healthy all winter by spraying the foliage with an antidesiccant at planting and apply one or two times during winter.

Water regularly, as long as the daytime temperature remains above freezing, and be sure the water drains effectively. Avoid ice damage to the root ball by not watering when the temperature drops.

When green boughs and red berries peek out from under a blanket snow, these planters look magnificent. Container gardening is a great and simple way to chase away the winter grayness and keep the beauty of plants in the garden all year long.
Vivienne Dieckmann, Sloatsburg, master gardener, Cornell Cooperative Extension of Rockland