I’m on a mission to plant a pear tree this fall in my small kitchen garden. In the past week, I’ve visited or contacted garden stores and nurseries within a half hour drive of where I live in central Pennsylvania—hardiness zone 5b. I’m ready now to concede that the local culture simply doesn’t believe in fall planting of perennials. That’s too bad for two reasons:
- Planting in the fall has many advantages (read about them here)
- I’m going to have to mail order my pear tree
What I’d Look for at a Nursery
As I explained in my last post (click here to read it): Were I there to choose the tree in person, it would have a straight trunk running vertically up to a healthy leader—with, perhaps, a bump where the leader was grafted onto root stock. I would not buy a young tree whose main trunk made an abrupt change in direction, or had one dominant branch that was obviously thicker and reached higher than the main leader. I’d also be cautious of the distribution of branches.
Sometimes, it seems nursery operators prize low branches. Young trees often come with branches starting within a foot of the ground which is not a problem unless the tree’s main trunk makes an awkward diversion from vertical. When a tree has a vertical leader, within a few seasons, you can prune away the very low branches, and encourage growth on the higher ones.
However, when a young tree’s leader is at the end of a horizontal branch nearly as thick as the main trunk, it may take many years of aggressive pruning to train a new vertical leader that’s even vaguely in line with the trunk. If you’re growing a very small tree, then low branches make sense. But I want to be able to duck under my tree’s branches, so it won’t do to buy one that a nursery assembled with one or more main branches three feet off the ground.
It’s about Assembly at the Nursery
When you’re shopping for fruit trees, chances are you’re looking at chimeras. A chimera is an organism assembled from parts of several organisms. Especially in the cases of dwarf fruit trees, but often with larger trees as well, a nursery worker, through a craft called grafting, has combined two or more types of trees to make a single tree. The worker cuts a scion (a thin branch with several leaf buds and a leader at its tip), from a standard variety of fruit tree—say, a Bartlett pear. The worker also roots a variety of pear tree that has specific desirable characteristics, but that may produce unappealing fruit. The worker preserves the roots and cuts off most of the above-ground leader, replacing it with the Bartlett pear scion.
Over the course of a few months, the select root stock melds with the scion, and new wood and bark grow together to make a viable tree. The nursery worker makes sure no leaf buds survive on the root stock, so the only viable growth above ground is the good-eating variety of fruit.
Why the Grafting?
In grafting, the nursery worker is creating a tree with the best possible combination of features. Often, a desirable fruit’s roots are vulnerable to diseases, but the rest of the plant is hardy. It makes sense, then, to graft the desirable fruit onto a different root that won’t succumb to disease.
To make dwarf fruit trees, a nursery worker selects a “dwarfing root stock,” and grafts a desirable fruit onto it. The dwarfing stock simply passes water and nutrients to the rest of the plant more slowly than the plant would like… acting, in effect, like a bonsai tree master who cuts roots off of plants so they’ll grow up small though proportioned just like normally-grown trees.
Grafting can result in trees with undesirable shapes—especially when the nursery grafts two or more scions onto a single root stock (this is advantageous for fruits that require cross-pollination and is also necessary if you want two or more varieties of fruit from a single plant). Only one scion can be the tree’s leader… others must be branches—and when you graft a branch onto a three-foot tree, you have a tree that wants to be in your way when you do yard work.
What’s my Next Step?
I want to order my new pear tree soon so I can add it to my small kitchen garden in October. I’ll browse on-line nurseries, make a list, and share it with you in an upcoming post. When I select a nursery, I’ll explain why. I’ll also order a tree and explain my thinking about it.