Choose a cold-hardy container
With the right pots, cold-tolerant plants, colorful twigs, and evergreen boughs, you can put together great-looking containers that will last till the weather warms and even beyond. Here’s how, courtesy of This Old House landscape contractor Roger Cook.
Water expands about 9 percent as it turns to ice, so even a one-time freeze can crack containers made of terra-cotta or other brittle, moisture-absorbing materials. Metal, plastic, and fiberglass are safe choices. Some ceramic containers can withstand a freeze, if they've been fired at high temperatures. And while standard concrete might break, concrete mixed with polymers stands up better. Wooden planters weather pretty well, too.
Roger lines wire window boxes with sheet moss, which adds color while holding back soil. Eco-friendly coir mats, made from coconut husks, do the job equally well. Here, sheet moss forms a base for the bright red berries and shiny leaves of wintergreen (Gaultheria procumbens). Taller variegated boxwood (1), miniature juniper (Juniperus communis ‘Compressa’) (2), and redtwig dogwood branches (Cornus sericea) (3) line the back of the wire window box.