Grandpa's "long winded" answer:
Of all the many questions people ask Grandpa, the most common is about rootstocks for fruit trees. What is the best kind for my soil? How big a tree will I have when it grows up? How can I mix different types of trees in the backyard orchard when they have different rootstocks? It doesn't need to be so confusing! When you find a variety you want to order at Grandpa's Orchard™, the question then becomes what rootstock will it be on and how big a tree will it grow into? When you look at a variety to order it, you will usually see the following information on one line: Grandpa's Format: Variety on Size of Rootstock (the actual rootstock), Grade of Tree Example: Golden Delicious Apple on Semi-Dwarf (M7) root, Extra Large 5/8" up caliper grade. This information tells the variety, which specific rootstock it is budded onto, and the size or grade of the tree. Rootstocks come in many "varieties" just like the fruit that is budded on them. Grandpa tries to keep it simple by only offering and recommending the ones that have proven themselves to perform well for the average person under most conditions.
Rootstocks are most often used to control total growth, impart precocity, and for specific soil adaptation : Most types of fruit now have rootstocks that control total growth or how large the tree will get by imparting a degree of dwarfness to the tree. A second desirable trait for a rootstock to have is to impart precocity or early bearing. In general, the more dwarf the rootstock, the more precocious the variety will be.. For comparison, most apple varieties on fully dwarf M 9 or B 9 will often start fruiting the next year after planting, while M 111, which is a semi-standard root, will often not fruit for 4-5 years to any degree. Apple seedling rootstock is even worse, taking 6-8 years for significant fruiting to occur. Grandpa does not offer it, and in fact, it is now almost unavailable in the commercial industry. There are improved dwarfing rootstocks for pear and cherry, which improve the production and efficiency of those fruits. Most stones fruits like peach, nectarine, plum, and prune are usually budded onto standard seedling roots, but because they are naturally smaller than apples, pears, and cherries, and much more naturally precocious, they will usually grow to about the same size as most semi-dwarf trees and will fruit early in life.
Grandpa tries to offer only rootstocks which are suitable for almost all conditions: The chart shows the rootstocks that Grandpa recommends. But to be a little more specific, Grandpa thinks that the following rootstocks will probably do the best for most backyard fruit growers:
- Apples: Semi-Dwarf M 7, Dwarf Bud 9, Semi-standard M 111
- Pears: Any will do fine, but OhxF roots are the most productive.
- Sweet Cherry: Gisela® 6 is the best. It will do well on all soils and will promote early production and good vigor. Gisela® 5 can be too dwarf and takes more work. Because Gisela® rootstocks are in such short supply and high demand, then Mazzard would be the next preferable choice for most soils. Mahaleb only for well drained, sandy soils.
- Tart Cherry: Mahaleb if you have sandy, well drained soil. Mazzard if you don't.
- Apricots: Manchurian apricot is the best for most soils. Peach root is OK for sandy, well drained soils only.
- Peach and Nectarine: Any peach seedling root should do as well as another, but not on poorly drained soils. St. Julian will do better on those.
- Plum and Prune: Myrobalan is best for wetter soils. Peach is OK for sandy, well drained soils. Since, not all rootstocks do well on all soils, and there are some rules that you will need to observe.
Rootstock Limitations: Not all rootstocks tolerate all soils. Grandpa will put it simply with the following "rules".
- Wet, poorly drained soils--- Don't plant trees on the following roots--- any peach, mahaleb, M 106 rootstock..
- Droughty soils: Don't risk planting M9, Bud 9, Gisela 5 rootstocks--- they may likely "runt" out.
- If you have soils that don't limit the rootstocks noted above, then almost all of the rootstocks that Grandpa recommends should do OK in your backyard orchard.
Planting Distance Apart: You can plant any distance apart you want, but realistically, you should not plant any closer than the tree will grow tall.
- Usually take the height you plan to let the tree grow and plant them about that close apart in the row.
- For the between the row spacing, add at least 6-10 feet, depending on how you plan to mow or keep the weeds and grass down. If you can plant your rows north and south, you will get the best use of God's sunlight. But, if you have really strong prevailing westerly winds, you may want to consider planting east and west. Don't put east-west rows too close or you will get shading from adjacent rows.
- If you are mixing apples, pears, cherries, and apricots with peaches, nectarines, and plums, you can see that by looking at the diagram above that you should stick with the rootstocks that will give you trees heights of 10-15 feet. Then you can typically space your orchard about 10-15 feet between trees and 18-22 feet between rows on all types of fruit and be happy.