Apple trees (Malus) are fruiting trees in the Rosaceae family. Some apple tree varieties are prone to biennial bearing, which occurs when the tree produces a heavy fruit crop one year and a sparse crop the next year. Biennial bearing occurs more frequently in trees planted in infertile soil and those planted in dry climates.
The Honeycrisp apple tree is a weak-growing variety prone to biennial bearing. Developed at the University of Minnesota in St. Paul, the Honeycrisp produces better quality fruits in the cooler regions of the United States. The blooms appear in mid-season followed by large yellow and red apples in the fall. These sweet, crisp apples ripen from late September through October. The fruit can be eaten fresh or used in pie and sauce recipes. The Honeycrisp apple tree reaches up to 20 feet in height and is susceptible to mite infestations.
The Paulared apple tree is an early-fall variety that reaches about 15 feet in height with a similar spread. This willowy tree is vigorous, productive and prone to biennial bearing. The apples are medium-sized, dark red fruit that ripen from late August through early September. The Paulared apples are very crisp and slightly tart right after being picked, but quickly become sweet and soft. This apple variety is commonly used in applesauce. Paulared apple trees are susceptible to fire blight, apple scab and powdery mildew. Pests are unlikely to attack the fruit because Paulared apples are very acidic.
Spartan apple tree varieties originated in British Columbia. This moderately vigorous variety produces high yields of fruit, but is prone toward being biennial unless thinned. The trees reach up to 15 feet in height with similar spreads. The firm, bright red fruit is small- to medium-sized and ripens in September and October. These apples store well for several months. Spartan apple trees are somewhat susceptible to cankers and apple scabs.
The Grimes Golden apple tree is a productive, vigorous variety first discovered in the 1800s by Thomas Grimes of West Virginia. White apple blossoms bloom in April followed by large, golden apples that ripen in September and October. Grimes Golden apple trees reach 15 to 25 feet in height with spreads ranging from 10 to 20 feet. This variety is susceptible to bitter pit and collar rot. Potential pests include plum curculio, codling moths and aphids.
Empire apple trees were developed at the New York State Agricultural Experiment Station back in the mid-1960s. This moderately vigorous, productive variety is prone to biennial bearing unless thinned regularly. The firm, greenish-yellow fruit ripens in September and October. The McIntosh-type apple offers a tangy yet sweet flavor. These trees typically grow to 12 feet in height and to 10 feet wide. Empire apple trees are vulnerable to apple scab, powdery mildew and juniper rust.