What to do during periods of Frost and Freeze Conditions
Normal winter time conditions in and around our lower desert areas include a few nights when temperatures may reach below freezing (32F) at official weather reporting stations (http://www.weather.gov/). In outlying and lower lying areas, actual temperatures may be even lower. During an abnormally cold period, temperatures can reach into the lower twenties or even colder. Temperatures below freezing can cause damage to certain varieties of trees and shrubs that are commonly grown in the area.How Frost Can Damage Your Plants
Frost damage is caused by moisture condensing on the leaf and forming ice crystals by drawing water from the plant. This dehydrates the plant and is why frost damage looks like a burn. Because many trees and plants become casualties during freezes, every effort should be made protect vulnerable plants to minimize winter damage.
Some trees and plants that are affected include, but are not limited to: Ficus Species, Jacaranda, Palo Brea, Pygmy Date Palms, Sissoo, Young Citrus, Bougainvillea, Lantana, Hibiscus, Thevitia and other varieties. If you have questions on the hardiness of your plants or how cold your particular area gets, please call your closest Moon Valley Nursery at 602-938-6666. Smaller and newly planted trees and shrubs tend to be the most susceptible to damage from cold weather. All trees and plants can benefit from the following measures to help prevent damage from frost and freezing conditions.
As weird as it may sound, the laws of thermodynamics prove that it is more difficult to cool humid air than dry air, so be sure to thoroughly water all of your trees and plants during periods of forecast frost or freeze. In addition, get your entire yard wet in the evening before forecast freeze. This boosts humidity in the immediate microclimate and will help minimize the effects of frost and freeze on your trees and plants
Where feasible, cover plants with a frost cloth or old blankets during nights of forecast freeze. It is important that you cover up before dusk. By the time it gets dark much of the stored heat in the garden has already been lost. Remove cover in the morning to allow radiant heat to be absorbed. DO NOT USE PLASTIC. Plastic actually increases the danger. For larger trees and plants, you can apply Frost Proof insulating spray. This applies a thin layer of wax-like substance that minimizes evaporation from the leaves, thus minimizing frost/ freeze damage. Both Frost Cloth and Frost Proof spray are available at all Moon Valley Nurseries www.moonvalleynursery.com .
People have had success in preventing frost/ freeze damage by stringing up Christmas lights in their trees. The older style lights (incandescent) provide the best warming effect. Sometimes it’s only a few degrees that will make a huge difference. Although these methods are proven to minimize the effects of abnormally cold weather on trees and plants, due to the uncontrollable nature of weather, there are no guarantees of success.