Answer: Unfortunately, plants can't withstand the New England winter temperatures in a window box because their roots get too cold in such a small amount of soil. For this reason, many gardeners will use greens such as clipped boxwood, evergreen boughs or swags, or even berried branches or colorful twigs as decoration, replacing them as needed during the winter. Another approach would pack the boxes tight with upright twigs and decorate them with twinkle lights or colorful ribbons. You can make displays using potted evergreens with the awareness that they most likely will not survive the winter in the box. Another idea might be to use seasonal pieces, starting with gourds in fall, followed by wooden cutouts in holiday shapes, and hearts for Valentine's Day, and fun flower shapes as spring approaches. With a little experimentation and creativity you can produce some great looking results.
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