When we appear at gardening events, or while reading our e-mail, certain questions appear over and over again. This page is a collection of those questions along with our answers.
You can always e-mail us with your questions at info@midfex.org. However, the best way to get your backyard fruit growing questions answered is to come to our events and to join MidFEx.
Why are fruit trees grafted?
The most important reason is that it’s a sure way to exactly propagate the variety we want, because it can’t be done by planting seeds. If you were to plant seeds from a piece of fruit, a Bartlett pear, let’s say, each seed would grow into a pear tree as expected, and each tree would eventually bloom and produce pears. But just as ten daughters can all be quite different from their mother, each daughter tree would bear pears that may not have much resemblance to the Bartlett pear you ate, nor to the other trees’ pears as well. Each daughter tree may even have growth habit or bark color different from its mother and its sisters. In order to be sure of having real Bartlett pears, a clone must be made, and the way it is done with fruit trees is by grafting. We must take a piece of a Bartlett tree (this piece is called a “scion”) and graft it onto some other pear tree, where it will “do its own thing” and produce Bartlett pears. Most woody plants of “named” varieties (‘Elberta’ peach, ‘Peace’ rose) are propagated this way, not by seeds.
You probably know that one can graft scions of 5 different varieties onto 5 different branches of an existing tree of the same species (apple on apple, pear on pear, etc.), thus making a “5-in-1” curiosity, but generally each tree is of a single variety, the scion having been grafted onto the lowest few inches of the trunk of a one-year-old tree of the same species, just above the roots. This baby tree of pencil diameter, which receives the scion and has its top cut off and discarded, is called a “rootstock,” and it and the scion remain together all their lives, the scion growing on to become the trunk of the final tree. (Of course, it is also possible to make clones by taking cuttings of the desired variety and inducing them to form their own roots, which is the way it is done with figs, grapes, and berry bushes, but for most trees the percentage of successes is not high. And more important, different rootstocks can be chosen to confer certain advantages to the final tree, as we will explain later.)
The scion, as we said, is a piece of the variety whose fruit we want. What is a rootstock? An apple rootstock, for example, is simply another variety of apple tree, the variety often indicated by a code like M-26 or B-9, which originally grew from a seed somewhere, was found to have something desirable as far as its roots were concerned, and is now itself cloned by a specialized nursery. This tree is entirely capable of living on its own; if nothing were ever grafted onto it, it would grow to maturity, bloom, and bear apples, although there is little chance that its apples would be of very good quality. But we are not interested in its more or less inferior fruit. We choose a particular rootstock variety only for its roots, which have one or more attributes that the roots of the scion variety may lack, such as disease resistance, ability to tolerate certain adverse soil or climate conditions, or tendency to cause the resulting grafted tree to mature sooner and be smaller and earlier-bearing than standard trees (“dwarfing rootstock”). Thus we want the rootstock only for what its roots can do, and the scion only for the fruit that its branches and leaves will produce. When the two are joined, we have a tree more desirable for our needs than either would be if growing on its own.
Why did my dwarf tree get so big?
Many mail-order catalogs and local nurseries sell fruit trees that are labeled as “dwarf,” but sometimes beginners in fruit growing are disappointed and inconvenienced when their so-called dwarf apple tree grows two stories high, after first taking 8 or 10 years to begin bearing fruit. Besides the possibility that someone simply made an error in labeling, there are two reasons why this might happen.
The first possible reason is that when the tree was planted, it may have been done in such a way that the graft union was set too close to the soil line, or even below it. Under these conditions, the scion, the part above the union, will sooner or later send down roots of its own. Remember that a dwarf fruit tree is created by grafting the desired variety onto a dwarfing rootstock. Each variety, however, still has all the genes to make its own vigorous roots if given the opportunity. Once these vigorous roots establish themselves in the ground, they will override the roots of the dwarfing stock and (in the case of apple and pear) go on to produce a standard tree, 20 feet high and nearly as wide across. This is the kind of tree that the kids can use for a tree house, and which will produce many bushels of fruit. Most homeowners, though, consider this too much of a good thing.
The second possible reason is that there is no real definition of “dwarf.” The seller was not deliberately misleading; it’s just that a “dwarf tree” is any tree that is smaller than standard–maybe just 17 feet tall when mature instead of 20. Trees this size might more accurately be called “semi-dwarf,” or even “semi-standard.” They are quite suitable for the commercial orchardist who wants a compromise between maximum yield per acre and the easier pruning, spraying, and picking of a tree that is only 2/3 or 3/4 as big as a standard tree, but for the backyard hobbyist, a fully dwarfed tree, one which is mature at 5 to 10 feet, is generally the most desirable. There are different rootstocks available for producing different-size trees according to the needs of the grower, although it should be noted that it is only in the case of apples that there is the fullest range of dwarfing rootstocks.
What is this on my apple tree?
You can download a copy of our Apple Scouting Guide. This has pictures of many of the pests of the apple tree. You need Powerpoint or equivalent to view this file.
Is there any difference in the size of the fruit grown on a dwarf tree as compared to a standard tree?
Absolutely not. It’s the tree, not the fruit, that is dwarfed. A dwarf tree just doesn’t produce as much fruit.
I planted a new apple tree this past summer and it seemed to take well. Today I accidentally broke off the main stem. Is it possible to repair this type of damage?
The bad news is you can’t really repair the main stem if it has broken off. The good news is that as long as the break is above the graft (attachment point of scion to rootstock), the tree will grow a new leader. You can help this along by pruning other potential leaders back and allowing just one to grow, preferably one that is fairly straight and near the center of the trunk. This leader will thicken in time, and the tree will continue to grow normally. However, if the break is at or below the graft, the new trunk will bear the inferior fruit of the rootstock; in this case the tree should be replaced.
When is the best time to prune a fruit tree that has been bearing fruit?
If your main goal is to invigorate the tree and encourage new growth, you should prune when the tree is dormant, typically in the winter, or at least fairly early in the growing season. Hardy trees such as apple or pear can be pruned any time in the dormant period. Cold sensitive trees like cherry and plum should be pruned closer to the end of winter.
What can I do to prevent my trees from overloading and possibly breaking their branches?
The best way to control this is with thinning of the fruit early in the season. If the fruits are growing in clusters, try to reduce the clusters to 1 or 2 fruits each. Also spacing between fruits should be controlled, especially if there are too many fruits for a given branch size and strength. Not only will this protect the tree from overload but the remaining fruits should be larger because the tree’s energy will not be excessively distributed. In general, recommended spacing for apples is 5-8 inches, pears is 4-5 inches, peaches and nectarines 5-6 inches, apricots 2-3 inches, cherries 1 inch, small plums 1 inch, and large plums 2-3 inches.
What are the advantages of planting dwarf vs. full size trees?
Typically, the dwarf trees will have a shorter waiting period for bearing fruit. This could be as much as 5 years difference in apple trees. They don’t spread out as much, so if space is a limitation, you can get more trees into any given area. Dwarf trees are typically 20 to 40 percent the size of a full tree. This translates into advantages when it comes to spraying, pruning, picking fruit, applying nets, etc. Generally people plant full size trees if they have lots of space and they want a larger yield of fruit. Most backyard orchardists generally are better off with dwarf trees.
Where can I find a supplier for a particular fruit variety?
The best source of this kind of information that we know of is the ‘Fruit, Berry and Nut Inventory’, which lists all the Nursery Catalogs and contacts for trees available by mail order. It is currently in its third edition and is published by the Seed Savers Exchange in Decorah, Iowa (ISBN 1-882424-57-3, soft cover). Besides trees and shrubs, this book also lists sources of rootstock. This book is available in soft and hard cover at Amazon.com other on-line bookstores. We also sell copies at our Fall Harvest Festival.