GARDEN CHORES: Prepare a plan for dealing with cold temperatures.
Our winters are often so mild there’s little frost. The average minimum temperature in our Zone 9 growing area is 20-30 degrees.
So even tender plants, such as impatiens and crotons, may pull through our winters. But gardeners should keep an eye on forecasts to be prepared for a freeze. Plants exposed to extended warm periods followed by a quick drop below 32 degrees are more vulnerable in cold temperatures.
Mulch beds heavily with pine needles, leaves or bark mulch. Water well when a freeze is in the forecast. Mulch and moisture help protect roots and ensure regrowth.
This is adequate protection formany shrubs that can withstand freezing temperatures, including abelia, azalea, boxwood, eleagnus, hawthorn, holly, ligustrum, loropetalum, mahonia, nandina, roses, wax myrtle and yaupon. When mid- to low 20s are forecast for several hours, many gardeners add protective row cover or blankets; azalea and camellia buds/blooms will die at these temperatures without adequate cover.
Duranta, hamelia, angel’s trumpet and root-hardy hibiscus may lose all or some of their tops in a hard freeze. But with water and mulch, they will likely
return from their roots in spring. Covering is optional.
Tropical hibiscus, often grown in large containers, will die in a hard freeze unless moved to shelter. Plumerias should bemoved indoors until spring.
When freezing rain is forecast, cover plants with sheets and blankets, then cover these with a heavier plastic and secure with bricks and stones. One-, 5-, 10- and 15-gallon nursery pots or large boxes can become mini-greenhouses to protect cool-season bedding plants. Sky-blue
forget-me-nots will show freeze damage without cover. Snapdragon blooms tolerate slight dips but show damage unless covered when it drops into the 20s. Uncovered petunia and primrose blooms tolerate short drops to the upper 20s. Alyssum, calendula, cyclamen, pansies and stock survive amid-20s dip without cover.
Do not wash frost/ice off plants the morning after a freeze. This raises the temperature too quickly and usually damages the plant’s cell tissues. Remove soggy, freeze-damaged plant ma
terial from soft-stemmed plants such as impatiens and begonias. Leave freeze-damaged parts on woody plants to protect green wood farther down the stem during future freezes; prune in early spring when there’s no threat of frost.
Also on the garden checklist
• Rake and collect fallen leaves; use as mulch or in the compost pile. Or bag raked leaves; add a little water tomake leafmold. Set bags aside and use at a later date to enrich garden soil.
• Plant cool-season blooms including dianthus, Drummond phlox, English daisies, ‘Osaka Purple’ mustard, Swiss chard, toadflax and violas in coolseason beds and containers.
• Plant daffodils now in
sun or semishade in welldraining, organic soil with 2 inches of soil above the bulb shoulder.
• Plant prechilled tulip bulbs through Valentine’s Day, depending on whether they’re mid- or late bloomers. Plant the bulbs with the pointed end up and the flat side of the bulb facing the front of the bed. Cover the bulbs with 3 to 4 inches of soil, then water. Plant in clusters of 12 among forget-me-nots and alyssum.
• Sow sugar snap peas. Add plantings of lettuce now through winter.
• Sow tomatoes and peppers indoors through mid-January. Transplant to the garden in March.
• Transplant azaleas and camellias.
• Plant trees. Watch the garden calendar for upcoming fruit-tree sales.
• Check dianella, dietes, hollies, euonymus and camellias for scale, and treat with dormant oil if necessary.