When the summer display is over, there is no reason to leave window boxes empty. There are plenty of plants that will look good through the winter. Choose from evergreens, winter-flowering shrubs, bushy herbs, cyclamens, winter-flowering pansies, primulas and bulbs such as crocus and snowdrops. With planning and imagination, your winter window box can take you from fall through Christmas and herald the arrival of spring.
Plants should be in frost-resistant containers, well-secured to the window ledge. Check the fixings before you start planting. Clean your boxes thoroughly of previous plantings and, ideally, replace the soil. For plants to survive the winter, they should not be competing with soil-borne bacteria or insects. Make sure the drainage holes are clear, and cover the base of the container with gravel, bark, terra-cotta shards or, if the weight of your box is a concern, lava rock, to ensure that frozen water does not paralyse the roots. Add a layer of potting compost or soil, and you are ready to plan your display.
Designing Your Display
Think about the effect you want to achieve: a mass of colour; subtle shades of one colour; a structured shape; an overflowing abundance, both trailing and climbing; or
a traditional mix of evergreen foliage and flowers.
You might choose to put fruit among your greenery for colour and then replace it with fir cones or Christmas lights for the holiday season. If you live in a very cold place, boughs of evergreens with berries for the birds or the rich red stems of dogwood will last well in the cold and augment the decorative effect. Try mixing the soft foliage of grasses with prickly, shiny holly or weaving a wreath of ivy around it all.
Flowers for Your Winter Window Box
Several types of flowers make a good display in a winter window box.
Cyclamen Persicum flowers all winter, and Cyclamen Coum blooms in early spring. Winter-flowering pansies come in shades of yellow, white, purple and red. They can endure deep frosts, and if you deadhead regularly they will keep flowering all season. Polyanthus and primulas flower in late winter in a variety of bright colours. Erica carnea provides a carpet of pink, mauve or white. Hellebore niger (the Christmas rose) is ideal for a window box because it brings its delicate beauty up to eye-level. Snowdrops need careful planning for inclusion since they need to be moved "in the green." Plant them in a box in early spring and leave them to die down over the summer in a shady place. You can then add other plants to the box for the following winter's display.
Planting and Care
Suitable foliage plants for window boxes are small conifers; shaped box; small shrubs like hebes; herbs such as lavender, rosemary and sage; and ornamental cabbages.
Arrange your plants in the container to see the effect before filling in with soil and firming in. Water in but never overwater. In dry and windy weather, check to see that the plants are secure and rooting nicely. Trim the plants to keep them in shape, deadhead where necessary and enjoy the fruits of your labour.