In general, the smaller the tree, the sooner it will bear fruit after planting. Thus, for example, the M.9 rootstock will produce a nonspur-type tree that is only 35 percent as large as it would be if grown on a seedling rootstock. The table also lists the time required for the trees to reach bearing age and the degree of rootstock resistance to two important diseases. Tree size shown as a percentage of the size the tree would reach if grown on a seedling, or standard, rootstock. Trees with a spur-type growth habit bear the majority of their fruit on very short branches called spurs.
Nonspur varieties produce fruit on longer branches.
Since spur-type varieties have fewer long branches, the trees are more compact. Because the choice of rootstock affects the size of the trees, it also affects the optimum spacing between the trees. Table 4 gives the recommended distance between trees for both spur and nonspur varieties. Note that very vigorous varieties should be spaced farther apart. For spur-type varieties such as Redchief Red Delicious, Starkrimson Red Delicious, Lawspur Rome, and Oregon Spur.