Gardening: Protecting plants from frost
Jan./Feb. 2011 California Country magazine
Story by Pat Rubin
Photo by Sarah Lee
Tips for overwintering your garden.
Water potted plants and move them to a protected spot.
Winter for many of us means a fire in the wood stove, a mug of steaming hot chocolate and curling up on the couch with a blanket and a book. But our precious plants are stuck outside. Look around and you'll already see evidence of Mother Nature's icy hand: Unripe tomatoes hang from limp, lifeless vines. The frost has turned tender succulents to piles of mush, burned citrus leaves, scorched geraniums and killed marigolds.
Not all plants are susceptible to cold and it depends on how long the freezing temperatures last. Conifers are tough. Deciduous trees—they lose their leaves in winter—will be fine. Herbaceous perennials—they die back each fall and reappear in spring—ought to survive, too. But every gardener I know has plants that need help to make it through to spring.
Here are a few tips:
- Water plants, especially potted plants. Watering provides protective moisture. When dry soil freezes, it pulls moisture from the root, causing damage. If the soil is moist, it can freeze without harming roots. The exceptions: succulents and tropicals. Leave them dry.
- Cover tender plants. Sheets, row covers, blankets, burlap, shade cloth or newspaper will give plants enough extra protection to survive a mild frost. For small plants, use sticks and pieces of cardboard or newspaper to make a tent. Remove covers in the morning after the frost has thawed. Don't let plastic touch the leaves, because it transfers cold to the leaves and burns them. Remove the plastic when it's sunny or it will get really hot beneath the plastic.
- Move potted plants to a protected spot. Warm walls, sidewalks or rock walls provide a few degrees of protection.
- Hang lights on citrus trees or tender plants. Use large bulb lights strung through a citrus tree or a 150-watt light bulb, especially on tender limes and lemons. If temperatures are in the 20s or teens, cover the plants. Water them. Harvest ripe fruit, but leave the rest.
- Roses should be dormant, but make sure they are well watered. Don't worry if roses still have leaves on them.
- Tropicals rot in cold weather, so keep them dry. That includes angel's trumpet, bananas and hibiscus. If the plants aren't big enough to cover, wrap the trunk so even if the tops are damaged or killed, the base and roots will be alive to resprout next spring.
- Wait to prune damaged limbs. Branches that snap and break when bent are dead. Branches that bend without breaking are still alive. But don't give up. Leave freeze-damaged limbs until spring. They offer some protection for the rest of the plant. The best thing for a frost-damaged plant is a good dose of benign neglect. Let them look ugly until spring.
Gardening to-do list for January/February
- Now is the time to peruse seed catalogs and plan this summer's vegetable garden. When you can't be gardening outside, you can dream about the garden inside.
- Don't prune perennials, shrubs or trees injured by frost. Wait until the weather is dependably warm. Otherwise, those fresh cuts could open plants to more frost damage if the weather turns really cold again.
- Spray the lawn with a pre-emergent to prevent crabgrass from germinating.
- Start tomato seeds indoors in small containers and put on a sunny windowsill or beneath grow lights.
- Apply a dormant spray on roses and deciduous fruit trees to smother overwintering insects.
- Pulling weeds by hand this time of year is easy because the ground is soft. Better to weed now than in a few months when weeds have taken hold and the task seems overwhelming.
- Start removing brush and weeds to create a defensible space around your home.
- Don't prune the lilac or forsythia. Otherwise you'll be cutting off this year's flowers. Do prune the butterfly bush.
- Plant cool-weather annuals like calendula, candytuft, forget-me-not, Iceland poppies, snapdragons, stock, sweet William and viola. Finish planting bare-root roses, fruit trees and shrubs.
- Plant gladiolus bulbs every three weeks until July for continuous bloom through fall.
Pat Rubin is a longtime gardener and garden writer. Send questions or comments to her at email@example.com.