I wanted to plant an European Plum tree. Originally I had only planned on planting only one but on different websites, different European plums show up as self-fertile. I was considering planting either an Early Italian, Italian, Stanley or Mont-Royal (all good in zone 5). My question is: 1. Which of these are self-fertile? I've read differing opinions, from all to none. 2. If you had to pick 2 to plant, which 2 would they be (based on taste)? Thanks, Lakshmi