Brrrr, it’s time to build a fire and put that extra quilt on your bed. And just outside, some of your more tender garden plants might need a blanket or a warmer location to survive Old Man Winter’s cold temperatures. Here are some ideas to protect these plants.
“First of all, it’s very important to read plant labels,” says Connie Skillman, owner of Pot Luck Container Gardens in Ashland. Labels tell you what winter temperature tolerance your plant has, but even plants that would be considered hardy in our (mostly) zone 7 climate may need some protection. We have many pockets of colder and warmer temperatures, she says. Plus, the roots of container plants are more susceptible to weather than they would be in the ground, especially in smaller containers. Large containers distribute temperature more evenly, whereas the dirt in a small, thin-walled container can actually freeze into a solid block, says Skillman.
Wouldn’t it break your heart to come outside on a cold winter day and find one of your beautiful pots cracked or broken and your plants all strewn about and frozen? Many people don’t realize winter temperatures can wreak havoc on terra cotta and ceramic pots if they are not treated properly. “Generally speaking, Mexican pottery is not fired high enough and is very porous,” says Dennis Trost, president of Southern Oregon Nursery. These will freeze and break quite easily. Bring them inside for the winter.
Terra cotta pots are usually a dull finish, adds Connie Skillman, owner of Pot Luck Container Gardens. Look for high-glaze, glossy and very heavy or thick pots. Italian or Vietnamese pots are usually winter-hardy and have labels telling you so. She says if the pots are stacked outside a nursery, that’s a pretty good clue they are winter safe. Sturdy plastic, fiberglass or wood pots are safe to leave outdoors for winter. Skillman lines the inside of metal baskets and cocoa fiber lining with a thin, plastic trash liner which she says holds moisture and acts as a barrier against the cold, so she can have hanging baskets outdoors all winter long.
“The reflected heat off a white south-facing wall will warm cannas and calla lilies, star jasmine, and some passion vines (Passiflora),” says Jason Hazeman, nurseryman at Southern Oregon Nursery. “If we have a mild winter, potted geraniums and begonias can be left outside. Bring them close to your house or under a porch or awning,” Skillman says. Don’t forget to water plants if winter rains don’t reach them. It is the very dry cold that is most dangerous to your plants. In-ground plants can be mulched with 6 inches to a foot of fine bark mulch or covered with a fabric blanket.
Skillman covers her geraniums and other tender plants with a thin porous sheet that allows rain and sun to come through, but protects from deep cold and winds. Be sure to secure the edges with rocks or pins to keep it from blowing off in heavy winds, she adds. Newspaper can be used to cover plants but it’s unattractive and tears apart. Plastic is OK to use in a cold frame, but should never be laid directly over the plant: it freezes, and doesn’t breathe or allow evaporation, so too much moisture may rot plants. It also intensifies heat so even winter sun can burn plants through the plastic.
Those of you who prefer not to take any chances with your prized begonias or lilies can dig the bulbs out of the ground or pot, trim off old flowers and foliage all the way back to the bulb, let bulbs dry out completely, and lay them in a single layer in a nursery flat. Store in a cool, dark and dry place such as a garage until spring.
Tender shrubs with woody stems such as some varieties of gardenia, some salvias or the yellow daisy (Euryops)can be wrapped in burlap blankets, says Hazeman. He has customers who have overwintered hardy banana plants with burlap.
Fuchsias, tropical plants, bougainvillea and citrus trees can grow all winter in a greenhouse. To put them into dormancy, store them in a building with minimal light and above-freezing temperatures. Do not fertilize dormant plants and water only when soil is very dry to the touch, perhaps once a month or so, says Skillman.
All is not dreary and dead in winter. “People don’t realize they can have beautiful color and texture all winter long,” says Skillman. Containers and hanging baskets with spectacular coral bells (Heucheras ), colorful winter pansies, golden and variegated grasses and evergreen ferns can keep your attention until it’s time for your well-protected tender plants to wake up.