University of Maryland Extension

Apples - Selection and Planting

red and green apple harvest

Photo: University of Illinois Extension Service

Selection

Because there are many insect and disease pests of tree fruits (especially apple and peach), it is very difficult to grow quality fruit in Maryland without some use of pesticides. To minimize
problems, consider purchasing disease-resistant cultivars. Pesticides may still be required,
particularly in wet seasons, but you can reduce the number of times pesticides are applied. Under normal conditions, you may need six to ten pesticide applications to produce fruit of reasonable quality. However, when disease-resistant apples are being grown, for example, only one to three pesticide applications may be necessary to control pests and produce high-quality fruit.

Cultivar Selection

  • Strains: Some apple cultivars such as Red Delicious and Golden Delicious are available in various strains. A strain is a mutation of a certain cultivar that has been selected and propagated for an improved characteristic. A strain may differ in fruit characteristics, growth characteristics, or both. There are many strains of some cultivars; for example, approximately 250 different strains of Red Delicious have been described and cultivated.
  • Spurs: The most common strain difference is between spur strains and non-spur strains. Spurs are short, stubby, slow-growing, modified stems that support multiple fruit blossoms and may remain fruitful for 7 to 10 years or more. They are common on apple, pear, and cherry trees. Spur-strain trees, because of their compact form of growth, are ideally suited for home gardeners with limited space. As a general rule of thumb, spur strains of a cultivar will result in trees only about 60% to 70% as large as the non-spur types of that cultivar. Fruit spurs and leaf buds are spaced closer on spur than on non-spur trees.
Apple cultivar selection (listed in approximate time of ripening)
CultivarComments

Bolded cultivars have some resistance to one or more of these diseases: fire blight, apple scab, cedar-apple rust, powdery mildew. They are highly recommended for the backyard grower. 

Crimson CrispBright red fruit with cream colored flesh. Moderately acidic with a spicy aftertaste. 
RedfreeEarliest scab and cedar-apple rust resistant cultivar; moderately resistant to fire blight. Red apple with cream-colored flesh. Excellent flavor; ripens mid-late August.
Ginger GoldBright yellow skin with pale flesh. Fruit is large and mildly sweet.
LibertyHigh-quality dessert apple. Red fruit; sub-acid to tart flavor. One of the most disease resistant varieties available.
GalaYellow skin with a bright orange blush; newer strains have more red color. Cream-colored flesh with a sweet-tart flavor. Very susceptible to fire blight and apple scab diseases.
FreedomSlightly less disease resistant than Liberty. Thick-skinned, red fruit with sub-acid flavor.
JonafreeDark, hard red fruit that is crisp and slightly tart.
EmpireMcIntosh x Red Delicious; dark red fruits of excellent quality. Good keeper; very vigorous, early-bearing trees.
Golden DeliciousGood all-purpose apple. Self-fertile, heavy producer. Fruit from spur strains tends to russet more than non-spur strains.
EnterpriseMedium-to-large, red, crisp fruit. Late blooming, moderately vigorous tree; keeps well.
GoldrushDeep yellow, crisp, firm fruit; upright, semi-spur tree; keeps well.
MutsuGolden Delicious x Indo; very large, light green to yellow fruit. It is a triploid and produces sterile pollen. Ripens mid-October.
StaymanDeep-red fruit with a rustic finish. Flesh is cream-colored, tart, and very firm.
BraeburnPale-green apple with a brick-red blush. Flesh is very firm and tart.

Tree Fruit Pollination

Rootstock

The two principal plant influences on tree size are the rootstock and the type of strain used (spur or non-spur). Other factors that will have an influence on ultimate tree size include general care, cultivar, soil type, earliness of fruiting, and time and severity of pruning.
Rootstocks influence not only the size of the tree, but also age of bearing, winter hardiness, and susceptibility to some diseases. Apples are the only fruit trees for which a wide range of rootstocks exist. (see Table below) There are few dwarfing rootstocks for other types of tree fruits available to home gardeners.

Benefits of Dwarfing Rootstocks

  • Earlier bearing
  • Harvest without ladder
  • Less pesticide used; better pesticide coverage
  • Improved cold hardiness and pest resistance
  • Less pruning required
  • Improved air circulation
  • Require less space; can be grown in small yards

 Apple tree spacings and probable yields on various rootstocks
Approximate
mature height (ft.)
Age at
bearing (years)
Approximate
lifespan (years)
Suggested
spacing in
and between rows (ft.)
Ave. yields
for trees at least
10 years old (bushels)
Dwarf
Malling 27*        6 - 8       2  10 - 15        5 x 13      1 to 1.5
Malling 9*       8 - 10    2 - 3      15       16 x 14       1 to 2
Malling 26 +, *      10 - 12    3 - 4      15        8 x 16       3 to 4
Semi-Dwarf
Malling 7 or 7A      12 - 15    3 - 4      20      12 x 20     10 to 12
Malling-Merton 111 #      12 - 15    5 - 6      20      12 x 20     20 to 25
Standard
Seedling     20 - 25    6 - 10     40      18 x 26    25 or more
Interstem trees #, ^      8 - 10    4 - 5   15 - 20      20 x 28    10 to 12

Key:
*requires support
+ Fire blight susceptible
# Malling-Merton trees require extremely well-drained soils to perform as advertised. Do not plant  them where drainage is slow or the soil is heavy clay.
^ Apple interstem trees are composed of either Seedling M106 or MM111 roots, a 6- to 8-inch stempiece of M9 or M27, and the scion cultivar on top. Pear interstem trees are composed of Quince root, a 6- to 8-inch piece of Old Home trunk, plus desired scion.
Source: Adapted from The Pennsylvania State Master Gardener Manual.

Planting of Fruit Trees

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