Hi, I'm new to the forum and am hoping someone can help. I've inherited a neglected plum 'tree' that was originally fanned against a wall I think, but has overgrown. Last year, some branches had some plums on them but the main branch had dozens of little hard round 'plums'- except they weren't plums. I'm wondering what they are and what to do this year to prevent them growing and encourage the others. Ihope this makes sense and thanks in anticipation!