Apple Tree

Asked July 14, 2017, 7:26 PM EDT

I have a granny smith and a yellow crisp apple tree in my back yard. This year the yellow crisp apples are completely different and have a texture and shape more like my granny smiths. Is this possibly caused by cross pollination?

Multnomah County Oregon

1 Response

Thank you for your question about your apples. Apple trees, like most other fruits, may be self-fertile (they can fertilize themselves), while other apple trees must be fertilized by the pollen from another apple tree (cross-pollination.) It is generally believed that self-fertile trees' apples taste better--and set more fruit--if they are cross-pollinated. Apple trees are divided into 4 groups (1 through 4, or A through D, depending on who is doing the categorizing.)

Your Granny Smith is in flowering group 3 and it is self-fertile. I cannot find a "Yellow Crisp" variety, but Honeycrisp is in flowering group 4, and needs a pollinating partner. (You can look up the flowering group for your apple variety on the Internet, if it's something other than Honeycrisp.) I suspect that, whatever it is, is needs a partner. Here's a link to an article about pollination and apples.

And, sure enough, once the cross-pollination takes place, the "new" apples--on both trees--will start to take on the traits of the other. (When done in the greenhouse or lab, controlling for wanted traits, it's called hybridization.)

Hope this is helpful.