So, I have a standard Methley J. plum that I planted as a bare root in 2014. Still no fruit. It started really slow but then took off in 2016 or 2017. It's now pretty large and a near perfect open center chalice shape from yearly pruning. It didn't flower until 2018 with just a few flowers. In 2019 it had a lot of flowers with not a single hint of fruit. This year it is loaded (right now 4/15). As an experiment this year, I bought a Satsuma tree that already had flowers on it and placed it right next to the Methley in the pot. It shouldn't need the pollinator though, just figured I would try before I decide to cut it down and replace with something that produces.

I'm in zone 6A. Recent low was about 30F. I even looked up last April temps and there was nothing under 29F after the first week of April so I don't think temperature is the issue (it's in full sun). I fertilize with Epsoma TreeTone the last couple years along with all my other trees. Belle of Georgia and 4x Asian pear produce well in the same garden area. I have apples that haven't flowered yet but they are healthy and on their way.

I don't think it's weather, shouldn't need pollinator, flowers just fine, what else could be happening here? Any chance it flowers too early for bees (do self-fertile even need bees)?