pruning plum trees (black knot)

[gixxerific]

Someone on my pit bull forum had a question I answered but but wanted to see what you thought. Here is what she asked.

So my fiance and I moved in to our first house in February. I noticed two young trees in our backyard have these weird black growths on them. I googled it and found out they are black knot on our plum trees. From what I can find, it says to prune in winter or very early spring. Here, it's been cold up until the past couple days when it's been 20degrees.

So what do you think, should I still prune?

[bullthistle]

Always prune when plants are dormant.

[dearmad]

em... not always.

Depends. With plums you risk exposure to killer things if you do it during a colder/wetter time period. Sometimes Plums are best pruned in Summer, especially if you're dealing with trying to rejuvenate the tree and not go for fruit. The pruning wounds will heal better, not likely be exposed to some killer mold (silver leaf comes to mind), and the tree will put energy into green growth.

Come on, let's not apply blanket rules to multiple species here, folks.

https://www.gardenersworld.com/how-to/projects/plums-prune/