Q: I have a Yoshino cherry tree that is showing signs of stress. It’s bleeding amber sap that turns rubbery, goes away, and then returns as a “bubble” of sap. This is in two spots a foot or so above the ground on the main trunk. It’s a stunning specimen with a marvelous shape even during winter.
Due to a foot injury, I’ve had to have someone else cut my yard this summer. Unfortunately, they had their mower set too low and scalped this root and one other in a couple of places. The injury appears to be healing, but is likely the source of the stress.
A: You have a nice looking tree! I don’t think you should do much: the ooze from the trunk likely came from infection that started when the roots were whacked. There’s no spray to counteract the infection, the tree will have to wall off the damage by itself.
To that end, you should apply a 3″ layer of pine straw under the tree and out to where your mulch ends now. That will protect the roots…but make sure to pull the straw back from the trunk at least 12″ to keep it dry.
Next spring, apply a granular, slow-release fertilizer like Osmocote or Dynamite at the rate outlined on the label.
Water if needed in drought and your tree should enjoy a long and healthy life.