I planted several apple trees this year. The one I bought today (a semi dwarf Granny Smith) had a little baby tree sprouting at the base. It seemed to be attached to the roots. I removed the sprout and wrapped its roots in a wet towel for now.
I am thinking about planting it, but I am wondering what kind of tree it actually is. I know that semi dwarf trees are actually regular trees that are grafted onto root stock. This sprout seemed to be attached to the roots, I am I right in thinking that it would in fact be whatever kind tree the root stock is?
Yes, it will be a clone of the rootstock variety - which won’t be much use as fruit, but you could use it as a new rootstock and graft any variety you like onto it.
It’s a variety of apple tree that has been selected for the shape of tree that it produces, rather than any aesthetic quality of the fruit - because the growth habit apple trees is significantly controlled by the rootstock.
If grown to full size, it will produce fruit of *some *kind - probably smaller, harder and more sour than average, because that’s the typical result of growing any apple tree from seed.
That’s what all apple varieties are - selections from trees grown from seed - the vast majority of which will produce worthless fruit - but one seedling out of many thousands may turn out to be a decent new fruiting variety, or a new and useful rootstock variety - but is very unlikely to be both - therefore, rootstock varieties grown to full size for fruit will probably disappoint.
Why not? I’d be curious enough to just stick it in the ground and see what happens in a few years. It’s free landscaping, free shade, and might have pretty flowers in the spring.