11/29/2016
Tips for Protecting Container Grown Perennials in the Winter
Winter container gardening is tough — you have to protect plants from wind, harsh sunlight and drying out. The biggest challenge, though, is guarding against root damage caused by rapidly fluctuating temperatures.
For USDA Zones 7 (most of Maryland) through 11, hard freezes may be infrequent to nonexistent, so adding insulation or bringing pots in for the winter may not be necessary. However, there are some chores that you should still be aware of...
Group several pots together on soil and close to the house or wall. Place the cold-hardiest plants on the outskirts of the grouping with the less hardy plants in the center. Put straw bales on the periphery. Putting them together increases the mass and volume of insulation and protects them from cold, harsh winds that cause desiccation and freezing.
For added insulation, mulch pots with straw, mulch or shredded leaves. Snow also acts as a good insulator. An interesting idea for insulating containers would be group pots together in a preformed pond liner and fill the liner with mulch.
If low temperatures loom, cover plants with cloth, burlap or plastic at night. If you use plastic, be sure to remove the covering during the day since temperatures can heat up, causing premature bud growth. Also, when covering, avoid damaging the top part of the plants. Injury sets up the plant for cold and pest damage.
Insert your pot into a larger pot for added protection. This will work best if the larger pot has thick walls or added insulation.
For plants in built-in boxes create a tee-pee type of structure around them. Do this by placing a few dowels in a tee-pee shape over the plant, leaving it enough room to stand, and covering the dowels with fabric or chicken wire and mossy material. Any structure like this will insulate the plant and protect its leaves, stems, and hopefully roots, from freezing and dying.