Seven or so years ago I embarked on the planting of an orchard, the goal being a wide variety of fruit growing in my backyard, something available for fresh eating most of the year. Some of it has succeeded, some has not.
One thing that has always puzzled me was the lack of fruit on my Green Gage plum. I had planted Coe's Golden Drop, another European plum, for cross-pollination. However any fruit that formed (a few did) disappeared from the tree shortly thereafter. Last year in disgust I dug it up. I'm still pulling out rootstock suckers.
Making one of my usual inspections I came across Coe's GD, which I had not yet got around to removing. To my astonishment, it has a dozen small fruits on it. And guess what --- they are apples! No wonder Green Gage never produced any fruit.
Apparently there is both a Coe's Golden Drop apple and a Coe's Golden Drop European plum. My source doesn't carry either of them currently but carried both the year I placed my order (probably 2006 or 2007). I got the wrong one, and embarrassing as it is for me to admit, I simply never notice. We see what we expect to see.
The apple tree, grafted on MM111 (which I also never noticed) is not at all vigorous. I'm trying to decide whether or not to keep it. The fruit is very small, almost like a Lady apple, though it has quite a nice snappy, vinous flavor. Like Scarlett O'Hara, I'll think about it tomorrow.