the problem would be no fruit. the "any apple or crabapple will pollinate" isn't quite correct, there are some apples that cannot pollinate any other apples, but will take pollen from other apple trees to produce fruit. i have several types of apple trees, so unfortunately i don't really know the compatibility of columnar and non columnar apples (i do have 4 columnar though). i create the columnar, i thought it was a specific branch from a tree that they would graft onto the rootstock to get this unique tree, which would mean it could pollinate what the original tree could.

I am not sure why they said that.......it is a pretty misleading comment and not at all true. Cross pollination only assures fertility - it's not like it will create some sort of deformed apples on either tree!! In fact, columnar applies were developed so that gardeners with small properties could enjoy adequate fertilization on any existing apples without needing to accommodate a full sized tree.

Most columnar apple varieties are pollinated by or will help to pollinate any pollen generating midseason bloomers.......your Honeycrisp fits into that category :-)

btw, the fruit generated by a columnar apple tree is pretty tasty.....but my experience has been limited to Northpole, Scarlet Sentinel and Golden Sentinel. They also produce early and heavily and will need thinning to be able to adequately support the crop.

Thanks, guys. Yeah, it just seemed like a "I don't know why but just don't do it" kind of answer. Are columnar apples just grafted on a narrow rootstock or are they genetically distinct? I've heard of triploid varieties that have more complicated pollination rules, but can't find anything about whether columnars are in that category. Gardengal, do you have a favorite for flavor?