I have a very large plum tree that I have grafted 21 plum varieties onto. I also have a combination plum tree about 200' away. It has 3 European plums and Satsuma and Santa Rosa. My problem is that every year the Santa Rosa foliage is full of holes and growth is very weak. The foliage of all the other plums is great. Online Santa Rosa is recommended 9 out of 10 times as a pollinator. What would be a good pollinator that I could graft onto the combination plum tree that would work for the Satsuma?

Santa Rosa is often not recommended for the PNW. I don't know where you live.

I had Santa Rosa. It was pretty good for a few years. Then it got sick and never fruited again. When I moved, I didn't bring a cutting, and i havent grafted it into my new tree at my new house.

Methley, Beauty, and Hollywood are often recommended instead.
John S
PDX OR

I have a ‘base’ Shiro Asian plum tree that pollinates well with the Satsuma (my favorite) grafted onto it. Bloom time definitely overlaps and Satsuma ripens a couple of weeks before the Shiro. A good combination in my isolated yard.