I think you should keep the Catalina plum. We picked these yesterday. They are small and look sad so I was going to make jam today until I tasted one. It was firm and sweet, a little tart at the skin that I removed. They will stay in the fridge for fresh eating. The bigger ones on other trees usually taste good but they are not ripen yet.
Your plums Looking very good and delicious.
Normally nurseries around here do not sell Catalina Plum tree. I got one from the food store outlets. They get their products from California. Hopefully nursery didn’t give wrong label on my Catalina as Emerald Beaut and take 3 years to find out . Too bad.
My Catalina Plum tree isn’t too big yet. I bought it only whip in last April 19.
I am sorry I can’t give you an answer. My place in southern California is mostly dry and hot year round, except for a few rainny days in winter, so black knot is not a problem.
Maybe @Vincent_8B can help.
@wfwalton
I am in zone 8b Seattle and my Catalina plum only a couple years old. So far it’s growing very well without much diseases. But I don’t think it’s very disease resistant. I think it’s just as normal as Japanese plum. Nothing special to me.