Agriculture Reference
In-Depth Information
Apple Rootstocks
The number of apple rootstocks is large and continuing to grow rapidly. Dur-
ing the late twentieth and early twenty-first centuries, many new apple root-
stocks were developed that provide size control, disease resistance, hardi-
ness, and adaptability to a wide range of growing conditions.
Unfortunately, a discourse on the history of apple rootstocks and the re-
lative merits of the many available is beyond the scope and intent of this
book. Instead, the following discussion provides rootstock recommendations
for various tree sizes and training systems. Many rootstocks are designated
by code letters followed by numbers. The letters refer to the place where the
rootstock was developed. “CG” refers to selections from Cornell's Geneva Ex-
periment Station. “EM” and “Mid-season” refer to East Malling rootstocks, and
“MM” refers to Merton-Malling rootstocks, both developed in England in the
early 1900s. “P” refers to rootstocks developed in Poland and “V” to Canada's
Vineland series.
Very Small Trees (3 to 6 feet tall)
Some apple rootstocks provide extreme dwarfing, producing trees about 15
to 25 percent the size of standard seedling rootstocks. While not generally
useful for commercial orchards, these very small trees have advantages for
home orchards where the trees are grown in tubs or on trellises to form ed-
ible hedges. The
M27
rootstock has long been popular for very small trees.
The
P22
rootstock produces trees about the same size as or a bit larger than
M27 and is probably a better choice in colder areas and where soils are on
the heavy side. The
Vineland 3
(
V3
) rootstock is especially suitable for cold
climates (Zone 3). All these rootstocks require supports for the trees.
Small Trees (6 to 10 feet tall)
Trees that are 25 to 40 percent of standard size are very useful for modern,
high-density plantings. The
M9
rootstock was long the industry standard for
small trees and still works well for arid and semiarid regions where disease
