In the Santa Barbara area we have many microclimates. Some of these are susceptible to frost damage in cold winters. If you live in the bottom of a canyon you know how chilly it can get.
Do not fertilize permanent landscape plants except for lawn, cool season annuals, and vegetables after October 1. This allows plants to harden off. Tender new growth is more susceptible to frost damage.
Keep your plants well watered. Damp soil retains more heat than dry soil. Mulch to trap soil heat and protect roots.
If frost is in the forecast, there are precautions you can take. Group tender container plants under eaves, against the house, under covered patios or large trees. They may be covered with sheets, blankets or products like row cover and insulation cloth. If you use plastic, make sure you stake it up, so it does not touch plants. You can string large bulb Christmas lights to keep plants warm.
Many plants don’t mind cold weather. Most of our trees and shrubs will be fine. It’s the plants of tropical origins that are very unhappy. Examples include: Hibiscus, Bougainvillea, Impatiens, Mandevilla and Ficus If you have tender plants you may cover them the same as your containers above. Make sure you uncover plants before the sun hits them the next morning.
If you get frost damage the most important thing to remember is: Do not prune off damaged foliage until new growth appears in the spring and all danger of frost is past. In Santa Barbara this is usually late February. Frost damaged leaves and stems may not be attractive but they will protect the plant from subsequent frosts.
After an occasional hard frost it’s a good idea to hose the plants off before the sun hits them.
Most established woody plants survive Santa Barbara frosts with minor injury. If you live in an area that freezes most winters its best to avoid tropicals. Watch for clear, cloudless, winter nights with low humidity. A great place to check the forecast is: http://www.nws.noaa.gov/ or 805 9886610.