Protecting citrus trees from frost helps to guarantee your annual crop. It doesn’t take long and is so worth the effort!
Here is our shortlist of important things to keep in mind:
- New citrus trees should be planted in the early spring to allow for root development before summer heat.
- Plants exposed in open areas to winds, especially in low areas of the garden, are most likely to suffer frost damage first, as cold air accumulates in such pockets. For protection, consider planting citrus trees near walls and fences, which trap and radiate heat.
- Before an expected frost, water trees well, but don’t get the leaves or trunk wet as they are most vulnerable. Keep the ground as clear as possible of weeds or mulch to allow for more heat to be retained from daylight sun.
- Protect young tree trunks with cardboard, wrapped tightly around the trunk just before nightfall, from the lowermost branches to the soil. Also consider covering trees with breathable, water permeable frost blankets for the night, and remove during the day.
- When frost hits, ice crystals form inside the plant cells, disrupting the flow of fluids, causing cells to break down.
Overall, when temperatures fall to 29°F for 30 minutes or longer, some frost damage to tender citrus plants will occur. Certain citrus – citron, lemon, lime, and Satsuma mandarins among them — are more sensitive than others.
- As applicable, remove frost-damaged fruit with cracked skin immediately to prevent fungus and mold spreading throughout the tree. (Yellowing leaves in winter are common, and may be a sign of over- or under-watering.)
- Wait to prune damaged branches until spring, to allow for further analysis and recovery in warmer weather. Remember to clean pruning tools to avoid the spread of disease.
Want more? Here’s our guide to California winter citrus.