Frost Sensitive Trees in Phoenix - Ficus nitida

Many people around our valley have beautiful Ficus trees and they sometimes can be affected by frost. Frost does not occur on a yearly basis but if it does occur here are some ways to help you understand what is going on and what to do in the event one of your trees are damaged.

When does frost occur?

• When temperatures are between 20 and 30 degrees Fahrenheit and this usually occurs between the months of December and Early February. Because each tree is different, the exact temperature varies based on species, location and even the height of a tree.

What to do in the event frost occurs.

Water

While this may not sound right it is exactly what is necessary to ensure your plants have the best chance of survival. Be sure to thoroughly water all of your trees and plants and shrubs during periods of forecast frost or freeze. The best time to do this is the night before the frost/freeze is due to hit. This will minimize the effects of frost / freeze on your trees and plants.

Cover / foliar sprays

Where feasible, cover plants/trees with a frost cloth or old blankets before a night forecast to bring a freeze. Don't use plastic - plastic increases the chance of freeze damage. For larger trees and plants, you can apply Frost Proof insulating spray. This applies a thin lay of wax-like substance that minimizes evaporation from the leaves, thus minimizing frost/freeze damage. Frost Cloth & Frost Proof spray are available at all Moon Valley Nurseries.

Heat

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. It may sound silly, but a few degrees can make a huge difference. There are other popular methods of protecting against freeze damage, but do to the unpredictable and uncontrollable nature of weather, they aren't guaranteed to work.

What tree sizes are most impacted?

• Young, actively growing, flowering, and/or dehydrated plants tend to be most vulnerable.

• The tissues that are affected the most are new growth and actively growing tissues

Planting locations for frost sensitive plants

• Place frost sensitive plants in sheltered locations. Western and southern exposures tend to be warmest. C Block walls, rocks and patios collect and reflect the heat of the sun. Full sun is warmer than shaded locations (though night temperatures, the cause of most frost damage, will be impacted by other factors) Place frost-tolerant plants that may blossom too early and thus risk flower and fruit damage in cold spots to prevent a premature break of dormancy.

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