Plum tree - Ask Extension
Our plum tree has green sacs growing along with the plums… is this normal and what is it?
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Plum tree #934983
Asked June 10, 2026, 12:20 PM EDT
Our plum tree has green sacs growing along with the plums… is this normal and what is it?
Bayfield County Wisconsin
Expert Response
Lisa,
I believe these are plum pockets, which are caused by a fungus called Taphrina communis. These guys are not uncommon in the Midwest. Thankfully, they do not seriously harm the tree, just reduce the amount of fruit. They are known to pop up after cooler wet springs and on trees that have native wild plum genetics.
If this is an issue, I would physically remove and dispose of the infected fruit before it starts to turn gray and produce spores. Future fungicide applications to prevent this are on the table---but often are more hassle and cost than it is worth.
Best,
Shane
