Past and present information on the grafting process when growing dwarf fruit trees.
Growing Dwarf Fruit Trees
Fruit trees don't grow true from seed, as you've discovered if you've ever sampled fruit from the seedling apple trees that sprout from bird or deer-scattered apple seeds in most old woods in North American farm country. The Golden Delicious apples or Montmorency cherries we enjoy today grow from fruiting wood taken from natural "sports"—genetic anomalies that jes' happened, often occurring on a single branch of a conventional tree, as did the original Golden Delicious on a tree in West Virginia back in the teens. Others are the work of hybridizers.
To produce a fruiting tree, a small branch of fruiting wood (scion) is cut and grafted—bound cambium layer to cambium layer—to a rootstock of a robust-growing seedling. Some propagators graft large stems to whole roots; others graft slips—slivers—of fruiting and rooting stock. The grafted tree is grown in a nursery for a year or more, till large enough to be dug and sold for replanting.
Years ago, experimenters like Luther Burbank and Bill Cahill discovered that when top-quality fruiting wood from trees that lacked high vigor was grafted to the roots of different but related plant species with a more vigorous growth habit, the union produced trees that combined the best characteristics of both parents. Most fruit trees are members of the same (rose) plant family, so they inter-graft readily.
Apple tree wood grafted to quince bush roots produced a bush-sized tree that produced full-sized fruit. Work with quince bushes at Mailing in England produced numbered rootstocks still in widespread use today.
Other combinations are being tested continually to grow ever more fruit of ever better quality in ever less space. One notable recent development is the rootstock that combines fruiting wood from good-eating sweet cherry trees with roots from distantly related Nanking-type bush cherries. The resulting dwarf tree (available in quantity for the first time this year) produces huge crops of succulent Bing-style eating cherries that cluster near the trunk, adopting the growth habit of the less-abundant and lower-quality Nanking-type stem-parent. This will make for easier picking and will keep birds from raiding your cherries as readily as they can with fruit produced out on the branches as on conventional trees.
Many dwarf trees with bush rootstocks suffer from flimsy bush-type limbs that are too weak to support their huge tree-scale crops. To counter this defect, plant breeders make "interstem" grafts, inserting one or more sections of different trunk woods between scion and root. Each added graft adds trunk or limb strength—as well as a dollar or more to the price of the tree. But paying a dollar not to have to worry about limbs breaking under a full crop or winter ice, and not having to set props under fruit-laden branches every September for the next 50 or 75 years is a dollar extremely well invested.
Every attractive new hybrid or dwarfing development is promoted heavily (often before fully proofed in nonexperimental orchards, and especially if plant patents give the developer exclusive sales rights for only a limited time). Nurseries are anxious to move out the investment they've made in young trees "while the new variety is hot," and might be tempted to exaggerate the virtues of an unproven development. Just be sure the new stock is well suited to your soil and climate before you invest in quantity. MOTHER suggests raising a sample of every potential addition to maturity and testing the fruit on your cusbillers before you commit a major part of your orchard. Back to Big Returns From Small Orchards