For the past two years, I have waited patiently for Honeycrisp apples to appear in the grocery store. At nearly $3 a pound, this is not an exceptionally affordable habit, but there is absolutely nothing nicer in the world than a nice crisp, sweet Honeycrisp apple. Since I now have a bit of room to stretch out, and an abundance of large buckets, I’m going to try and grow apples in containers next year. After scouring the Kentucky Agricultural Extension, this will be more than possible. For the first few years, I’m going to try and grow 1 HoneyCrisp and 1 as-of-yet unknown tree, plus 2 rootstock trees. I’ll be planting them in 5 gallon buckets at first, fully expecting them to outgrow this pot after a couple years. Since they’ll be planted in a bucket, they’ll need regular irrigation and fertilizer. With only four trees, I’ll be more than able to provide this. How will an apple tree fit in a pot, though? I’ll be planting a dwarf variety, which I will keep pruned to about 6 feet tall.

After reading quite a bit, there are a few important things to remember about apples:

• Apples are not self-fertile. With the exception of a few varieties, all apples will need another type of apple in order to pollinate and bear fruit. These trees need to be within a couple dozen feet of each other. Further, you have to pay attention to the blooming time of the cultivar you’ve selected. Late blooming plants will not pollinate early blooming plants. Further, it’s infuriating to try and figure out what apples are able to pollinate which others. The best guide I’ve found so far is here.
• Apples cannot be grown from seed. Apples do not breed true, and if planted from seed, you’ll end up with bitter crabapples after just a few generations, unless you breed them under laboratory conditions. Each cultivar you find in the grocery store is a clone of every other apple of that cultivar. Furthermore, because breeding has to take place carefully in order to get a tasty apple, it is difficult to breed an apple that is both tasty, and has a robust root system. Since fruit trees take well to grafting, trees bred specifically to become rootstock are created, and used as the root system of a tastier plant. This is what you’re buying when you buy bare root stock: one year old grafted trees.

There are lots of different rootstocks available for different needs. Roots determine characteristics like disease resistance, resiliency, and final tree size. As a result, the rootstock selected is especially important for backyard gardeners. A full size apple tree may top 25 to 30 feet. A semi-dwarf tree is a more manageable 12-20 feet, while dwarf trees are a mere 5-12 feet tall. In my case, obviously, dwarf trees are the only choice.

A quick summary of some different rootstocks:

M27: The smallest of all the dwarf rootstocks.  This tree must absolutely be supported, or it will buckle under its own weight.  This tree is ideal for planting in pots, but is disease prone.  Furthermore, setbacks which may cause a larger tree to give a low yield would kill a tree this small.  As a plus, however, these trees will often begin producing in their first year.

M26: A slightly bigger, but more venerable dwarfing rootstock.  As big as 10 feet tall, this is common in home orchards and market gardens.  Fairly disease resistant, M26 needs well drained soil.  Almost every nursery stocks trees of this type.

Bud-9: Same size as M26 (roughly), but more disease resistant, and cold hardy.  Recommended here in Kentucky, but more difficult to find.

So, the plan as of now is to raise 2 trees on B9 rootstock (if I can find any nurseries selling trees on this rootstock next spring), and two rootstock plants to propagate new plants with.  Right now, it looks like Van Well Nursery has the best selection of the trees I want in B9, but Burnt Ridge has a better selection in M26.  We will see where we are in a few months.

Sources:

http://www.ca.uky.edu/agc/pubs/ho/ho39/ho39.pdf

http://www.ca.uky.edu/agc/pubs/ho/ho82/ho82.pdf

http://www.wvu.edu/~agexten/hortcult/fruits/om100.pdf

And many, many others.