Standard-size pear trees reach 30 feet tall. Even if you have the room for a tree that size, the fruit from its upper branches can be hard to harvest. That's why most home pear growers choose dwarf or semidwarf varieties. (Bonus: Smaller trees start bearing fruit sooner than full-size trees; more on this in the next section.) Like most fruit trees, pear trees are typically grafted—the variety you choose is attached to a rootstock that determines the tree's size.
The traditional rootstock for dwarf pears is quince, which produces a tree that is 8 to 10 feet tall. Not all pear varieties take to grafting onto quince rootstock. It is reliably hardy only to Zone 6, and it's shallow-rooted and therefore less drought-tolerant.
Another option, especially in colder climes, is a semidwarfing tree, typically grown from rootstocks designated as 'Old Home' 5 'Farmingdale' or OH5F. These rootstocks are hardier than quince and produce a tree 60 percent to 70 percent as tall as a standard tree. To find out which rootstock and variety combination is best for your growing conditions, look for a nursery in your region and ask questions before you buy.
Prepare Before Planting
Take time to have a spot for your trees carefully chosen and well prepared before they arrive. "Get the soil right," Stella Otto advises, "then get the trees." Pears are usually sold as one-year-old, unbranched "whips." Dwarf varieties begin to bear fruit three to five years after the whip is planted; semidwarfs produce a full harvest in five to seven years.
Plant pear trees in full sun and give them good air circulation and deep, well-drained soil that's slightly acid (pH 6.4 to 6.8). Set them so the graft unions are 2 to 3 inches above the soil surface. Give each 5 to 10 pounds of composted manure to start; mulch the trees generously; and for a few years, be sure they get 1 inch of water a week either from rainfall or your hose.
How you feed and prune your trees will affect not only their size, shape, and yield but also their ability to withstand fire blight, which thrives on lush, new growth. Left to their own devices, pear trees will shoot straight into the sky. Add too much nitrogen to the soil, and you'll only encourage vigorous, blight-prone, upward growth, which also will delay fruiting and diminish dwarfing. Prune too often, and the same thing will happen. You can train a pear tree so it has one central leader, or main trunk, or you can keep two or three leaders, so you don't lose the whole tree if fire blight strikes one leader.
"Put your pruners in the closet for the first few years and lock the door," says James Cummins, an experienced pear grower and nurseryman in Geneva, New York. It's far more important to frustrate the upright growth by spreading the branches each spring so they grow roughly 60? from vertical. Use a stick notched at each end to spread apart two branches, or hang a weight near the ends of branches to hold them down. Do this in spring, just after petal fall. Cummins also recommends using a spring-type clothespin to establish a wide crotch angle when shoots are about 6 inches long.