When autumn rains begin and dreary days turn into winter, many gardeners clean summer annuals out of window boxes and forget about them until spring. Perhaps a Halloween ghost or extra evergreen bough makes its way to the window but mostly, the box is left empty and dreary. Planting those window boxes through autumn and winter will brighten your windows and spirits, no matter where you live.
Window boxes accent the "lights" or windows of the home. They are visible from inside as well as from the outside and mark the boundary between home and the rest of the world. They are compact enough to provide even urbane city dwellers with a garden and picturesque enough to find themselves at home on a rural farmhouse. Whether filled with pansies and geraniums, herbs or miniature roses and lady ferns, window boxes are expressions of the personalities of those that dwell within.
Window boxes are filled with living flowers and foliage beginning as soon as spring frost permits---usually before the garden can be planted. They bloom all summer with periodic changes as the season progresses but fade when the leaves begin to fall. When fall comes, though, garden chores wind down and cool, rainy weather often signals the end of window box floral beauty, especially in colder climates. Think of the window box more as a craft project than an extension of the garden during the dark months. Better still, encourage children to use autumn and winter to use the box to make a contribution to the environment.
In warmer areas, herbs and leafy vegetables can be grown throughout the winter---a boon to both kitchen and traveling birds. Mums, asters and ornamental kale and cabbages can grow happily in most North American boxes through the autumn. Really cold weather calls for more creativity, though; when the sun hangs low in the sky, growing days are too short to support living plants.
Fill autumn and winter boxes with seasonal foliage. Cut growing plants instead of digging them up to form a base in which to anchor branches. Collect attractive foliage to dry during summer and fall. Grow strawflowers in the summer garden to use with small squash and gourds in the autumn window box. Add multi-colored "Indian corn" for the birds; they scramble for food as the days grow short.
Continue feeding the birds and other small wildlife through the winter by tucking branches of real pepper berries, crab apples juniper berries or purple plums---whatever grows in your yard that the birds will enjoy. Use one or two types of evergreen foliage and some holly, winter creeper or pittosporum for interest. In cold areas, help children make a natural bird feeder by anchoring newspaper with bright brush like native redosier dogwood and sprinkle seed each week to bring birds to your window all winter long.
Avoid using plastic or silk flowers that are obviously out of season and unpalatable or dangerous for birds and scavenging small animals. A poinsettia in December is acceptable because it is traditional but a stand of tulips and daffodils looks cheap and out of place. Use natural plant materials and minimize the use of ribbon, paper and other materials that can droop or shred in autumn rains and winter winds.