Coe's Golden Drop European Plum

I notice a lot of your European plums are zone 5 or higher, including this Coe's Golden Drop. Living on the border of where USDA zone 5 and 4 meet, do you think that I could plant a zone 5 plum? We hardly ever see temperatures below -10 or -15 for context. Thanks!

Provided you kept a heavy mulch it would probably be okay. Unfortunately "hardly ever" can still mean the death of a tree that is marginal in your zone as all it takes is one bad winter to take it over the edge. Winter protection stratagies can help you push your zone though, so it's really up to how you care for it!

I was considering this as a pollinator for Parfume de September. Would I then get fruit on both trees?

Not likely. Coe's needs another non-mirabelle for pollination as mirabelle plums are terrible at making pollen.

i read that coes golden drop needs Mount Royal or Stanley to pollinate. how ever I don't see these trees for sale here. do you have any?

Coe's Golden Drop will cross polliante with most, non-prune, European plums - not just the two listed above.

what plum will pollinate this tree?

Most other European plum, except for Mirabelle plums.

Can Stanley pollenize Coe's Golden Drop?

Yes it can!

Does this Plum ripen in Western Washington?

It absolutely does!