What kind(s) of plum are there? What is the rootstock type? Just curious.

I'd remove most vigorous uprights and about 90% of them. Leave any less vigorous shoots. Do it about a month or two ago. Where you are you can do it now but the benefits will be less.

Thanks. I know one is supposed to trim less aggressively in the summer but these verticals are insane.

I don't know the root stock. The tree was a gift. It has 2 purple fruit types, 1 rounder DEEP purple fruit type and 1 golden type. For some reason only the golden ones came out much this year.

My concern is getting the fruit back for next year.