Flowering crabapples are highly regarded trees for landscapes. At under 40 feet, the trees are small enough to fit into most yards without interfering with utility lines and walkways. They have characteristics for every season, including red flowers, red fruit, autumn colored leaves and interesting bark. Crabapples have a number of interesting forms, such as rounded, upright, weeping, dense and mounded. They are adaptable to various soils and climatic conditions. To top it all off, they provide a natural habitat for small wildlife.
Most flowering crabapples are sold as bare root plants at heights of 3 to 6 feet. The roots must be kept covered and protected during transplanting so they remain moist. Wet burlap or sawdust will keep them safe until planting. Make sure the soil has a crumbly texture because root-establishment is hindered by compacted soil. Spring planting is best, in well drained soils. The trees are adaptable to various soils but they prefer a soil pH of 5.5 to 6.5 for best growth.
Dig a hole that is wider than the root ball. The tree can be planted to the same depth as the nursery grew it, but the roots need to have some room at the sides to get established without being crowded. Replace the soil around the roots and tamp lightly. Water the tree slowly for good soil-to-root contact. Mulching helps trees retain moisture levels. As a rule, the tree needs an inch of water per week during the first year.
Crabapple trees don’t need fertilizing during the first year. Extension specialist R. E. Durham at the University of Kentucky recommends using 15 to 20 pounds of 10-10-10 fertilizer once per year. Most tree roots grow in a circular pattern 20 feet from the trunk. This equals out to an average of 1200 square feet of root space. Keep this in mind as you fertilize. Use gloves to hand-spread the fertilizer over the entire area.
There are a number of diseases that affect crabapple trees, including apple scab, fire blight, cedar-apple rust and powdery mildew. In addition, some varieties are a favorite target of Japanese beetles. Extension professor Robert E. McNeil and plant pathologist John R. Hartman at the University of Kentucky evaluated 46 cultivars of crabapple trees to measure crabapple growth, ornamental value and resistance to disease and pests. Keep in mind that these findings were specific to Kentucky, USDA planting zone 6, where winter temperatures are sometimes -10 Fahrenheit.
Drs. McNeil and Hartman found excellent disease and good pest resistance in several cultivars. ‘Christmas Holly’ crabapple grows 10 to 15 feet, has gold autumn color, white bloom and red fruit. Malus floribunda grows 18 to 25 feet, has pink and white spring flowers, gold autumn color and red fruit. ‘Tschonoskii’ grows 30 feet, has gold autumn color, pink and white flowers and yellow-green fruit. Other favored varieties were ‘Silver Moon’, ‘Profusion’ and ‘David’, among others.