Avocado trees have a paper-thin bark that offers little protection from the sun. They are susceptible to sunburn and heat stress when young or whenever the leaves are lost due to wind, freeze damage or defoliation of any kind. Whitewashing the trunk and branches protects the avocado tree from the sun until the leaves can recover.
Mix equal parts of white interior latex paint with water. The University of Florida IFAS Extension recommends a mixture of 10 parts water mixed with one part zinc sulfate when latex paint is not available. Mix well, then add 10 parts of fine hydrated lime. Mix thoroughly and add more water if needed to thin the solution for spraying
Spray or paint the whitewash onto young trees immediately after planting. Strain the solution, if needed, when using a sprayer. Coat the trunk and exposed branches, avoiding the leaves.
Coat the exposed trunk and branches of all avocado trees with the whitewash solution immediately after a freeze, hurricane or leaf drop for any reason. Even a small amount of sun can damage healthy trees when the leaves fall off.