Rootstocks

Most home gardeners prefer small, size-controlled fruit trees grown on "dwarfing" rootstocks. Smaller trees make picking, pruning, and pest control easier, and they set fruit at a younger age than full-sized trees.

Rootstocks for apple trees are special apple varieties that control the height of the tree and give it other special characteristics, such as resistance to insects or diseases, solid anchorage in the ground, and early fruit production. A cultivar is grafted onto this special rootstock, so you are essentially buying two plants—the rootstock that anchors the tree and the cultivar that produces the fruit.

In this publication and elsewhere, you may read references to "dwarf apple cultivars." This is usually shorthand for "apple cultivars grown on dwarfing rootstock." For example, the cultivar Yellow Delicious can be grown on a dwarfing rootstock or on a rootstock that allows it to grow into a full-sized tree. This is different from most landscape trees, where dwarf cultivars are distinctly different genetically from their full-sized relatives.

Mature tree size depends on the vigor of the rootstock, the scion cultivar (the cultivar grafted onto the rootstock), the depth and physical characteristics of the soil, and cultural practices. Fully dwarf apple trees grow just 8 feet tall when fully mature at 15 to 20 years of age. The fruit of a small tree is as good in flavor as, or better than, the fruit of the same cultivar grown on intermediate- or full-sized trees.

Common apple rootstocks include:

  1. 9—A strongly dwarfing rootstock that produces a very short, 8- to io-foot-tall tree (see Figure 1). It needs a soil with high water-holding capacity and good drainage. Plants should be staked or trellised, and they are very susceptible to the disease fire blight. Trees grown on M.9 rootstock can bear fruit the second or third year after planting and reach full production in six years.
  2. 26—Produces slightly larger, 11- to 14-foot-tall trees that tend to be poorly anchored in the ground. Trees must be planted in well-drained soil but cannot tolerate very dry conditions. Trees grown on M.26 root-stock can bear fruit the second or third year after planting and reach full production in six years.

Sure-Fire Winners

These apple cultivars are easy to prune and set fruit most every year. (You'll still need to tend to pest management.)

  • Jonamac
  • Sansa
  • Liberty
  • Empire
  • Golden Delicious
  • GoldRush

Fruit trees grown on dwarfing rootstock bear fruit sooner and are easier to manage.

Table 3: Recommended tree fruit cultivars (listed in order of ripening for each fruit type)

Fruit

Cultivar

Fruit

Cultivar

Apple

Apricot

Cherry, sweet

Cherry, tart

Nectarine, yellow flesh

Williams Pride*

Sansa*

Gala

Jonamac

Freedom*

Priscilla*

Liberty*

Empire

Golden Delicious

Keepsake

GoldRush*

Harcot Harogem Harlayne Goldcot

Stella

Emperor Francis Royalton Hartland Hedelfingen

Montmorency Balaton

Pocohontas Mericrest Nectared 4 Nectared 6

Nectarine, white flesh

Peach, yellow flesh

Peach, white flesh

Pear

Plum, Asian

Morton Nectacrest

Harrow Diamond Brighton Redhaven Madison

Canadian Harmony Cresthaven

Surecrop Raritan Rose Eden

Bartlett

Gorham

Bosc

Plum, European (prune)

Green Gage Richards Early Italian Stanley

French Damson

Early Golden

Shiro

Seneca

* Scab-resistant apples

  1. 7—Produces 15- to 18-foot-tall trees with deep roots. But if for any reason the soil has a restrictive layer, trees will be poorly anchored. Roots also are susceptible to root rot and crown gall diseases. Trees will take at least one year longer to fruit than those grown on M.9 or M.26 rootstocks, usually bearing in their third or fourth year after planting and reaching full production in 8 to 10 years. These trees are a good size for planting in areas with heavy deer pressure if you can protect them from browsing deer when they are small.
  2. 106—Produces large, 18- to 20-foot tall trees, nearly standard size. Trees often grow late into the fall, making them more susceptible to winter injury. They will not tolerate poorly drained soils, and collar rot

Figure 1. The type of rootstock that apple varieties are grafted onto determines the mature height of the tree. For example, M.9 rootstock produces an 8- to 10-foot-tall dwarf tree that can be pruned and harvested from the ground. Varieties grown on M.111 rootstock grow to be 19 to 24 feet tall.

Figure 1. The type of rootstock that apple varieties are grafted onto determines the mature height of the tree. For example, M.9 rootstock produces an 8- to 10-foot-tall dwarf tree that can be pruned and harvested from the ground. Varieties grown on M.111 rootstock grow to be 19 to 24 feet tall.

is a common problem. Trees grown on MM.106 rootstock can bear fruit their third or fourth year after planting and reach full production in 8 to 10 years. These trees are a good size for planting in areas with heavy deer pressure if you can protect them from browsing deer when they are small.

MM.111—Produces large, standard-sized, 19- to 24-foot-tall trees. Roots tolerate a wide range of soil conditions, including dry soil, and plants are less subject to collar rot than are those grown on MM.106. Trees grown on MM.111 rootstock can bear fruit their third or fourth year after planting and reach full production in 8 to 10 years. These trees are a good size for planting in areas with heavy deer pressure if you can protect them from browsing deer when they are small.

The recently developed Cornell Geneva rootstock series has two rootstocks that are highly resistant to fire blight:

  1. 16—Produces dwarf trees similar in size to M.9. The trees are very productive at an early age, fruiting during the second or third year and reaching full production in six years.
  2. 30—Produces mid-sized trees similar in size to M.7, but it sets fruit a year or two earlier and produces fewer root suckers.
  3. 9 is a fully dwarfing rootstock similar to M.9 but more cold hardy and fire blight resistant.

Size-controlling rootstocks are also available for other tree fruits. For pears, Old Home x Farmingdale rootstock offers good fire blight resistance. OHxF 333 performs well in New York and produces trees that are about 10 to 12 feet tall. Pear trees grown on OHxF 97 rootstock are nearly as tall as standard trees but produce fruit much sooner.

For peaches, Lovell and Bailey are acceptable rootstocks wherever peaches can be grown in New York and produce 12- to 15-foot-tall trees.

Plum and prune cultivars grafted on sand cherry or Nanking cherry rootstocks grow just 15 feet tall. Plum trees are commonly propagated on Prunus St.

Apple trees can grow from 8 to 24 feet tall depending on the rootstock you choose.

Julian A and myrobalan (Prunus cerasifera) rootstocks. Myrobalan grows in a wide range of soils, including poorly drained sites.

Cherry trees were traditionally propagated mostly on Mahaleb and Mazzard rootstocks, which usually don't produce fruit until about their seventh year. Mahaleb is the more winter hardy of the two and produces a smaller, 15- to 18-foot-tall tree. However, it is damaged by collar rot in poorly drained soils. Mazzard rootstock generally produces larger, 24- to 28-foot-tall trees and is preferred for sites with questionable drainage. Giessen rootstock, developed in Germany, produces smaller trees and begins fruiting as early as the third year.

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Responses

  • marley
    How to prune a jonamac?
    7 years ago
  • maik
    How to grow Mazzard rootstocks?
    7 years ago
  • morgan
    How tall lovell rootstocks grow?
    7 years ago
  • ulpu
    How to propagate mazzard?
    7 years ago

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