Do you have a stone fruit tree (cherry, plum or peach) that has ugly gooey stuff seeping out of the bark?

Gummosis is the generic name for the oozing of sap from the wood of a tree. Stone fruit trees such as cherries, plums and peaches have thin bark and are susceptible to all sorts of injury. If injured stone fruit trees will exude a jelly-like gummy substance in the spring season.

Gumming is a response to physiological stresses or physical injuries. Gum is exuded due to a variety of factors, including insect borers, fungal diseases or physical wounding. Gumming can also be caused by poor growing conditions such as trees being planted too deep, compacted soil, excessive moisture, excessive dryness, sunburn, frost damage or too much shade. Often, if the oozing gum is clear, the problem is caused by a non-living (abiotic) factor. Or, if the gum is not clear then it may be caused by an insect or disease injury.

There is nothing you can do to fix gummosis. However, infection can be prevented by maintaining good tree health with proper horticultural practices; prepare soil at planting, use proper planting techniques such as planting trees at the proper depth and removing packaging materials, avoid over-mulching, avoid physically injuring branches or the trunk, prune correctly during the dormant season and maintain adequate moisture. Healthy plants can fend off damage from insects and diseases.