Our autumn purple ash developed hickory nut size growths all over the tree. What are they and will it hurt the tree?
These growths that start out green and eventually turn brown are ash flower galls. Tiny mites feed on the male flowers causing the plant to form these growths. The galls are unsightly but do not hurt the trees so there is no need to treat. The growths will eventually fall off the branches. Sweep and dispose of the mess. Keep your tree healthy and better able to tolerate these and other pest problems with proper watering and mulch. Water established trees during extended dry periods. Thoroughly moisten the top 12 inches of soil under the canopy of the tree. Water again when the top few inches of soil begin to dry. Spread a 2 to 4 inch layer of shredded bark or woodchips on the soil under the tree. Leave a little space between the trunk and mulch.