Flowering Crabapple Trees Fact Sheet No
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Flowering Crabapple Trees Fact Sheet No. 7.424 Gardening Series|Trees and Shrubs by J. Klett and R. Cox* Flowering crabapples (Malus species) the messiness of large-fruited crabapples Quick Facts are popular ornamental trees in Colorado should be aware that many newer varieties landscapes. The Front Range is known for its have smaller, persistent fruit. Larger-fruited • Crabapples are popular trees crabapple flowering, announcing the arrival crabapples are valued for making jams and closely related to apples, but of spring. jellies. with smaller edible fruit. They Crabapple blossoms appear in April Some varieties of crabapple have may also differ in leaf color, to May, depending on variety and showy fall leaf color, ranging from yellow growth habit, flowering time elevation. Some crabapple varieties bloom to orange to red and purple. Crabapple or flower color. relatively early, others bloom mid- season twig and bark color ranges from green to and some bloom towards the end of yellow to reddish brown when young. Many • Crabapple trees are fairly crabapple season. Crabapple flowers may crabapples develop attractive mottled bark drought tolerant. They can be be single (5 petals), semi-double (6 to 10 as they mature. low maintenance and versatile petals) or double (more than 10 petals). Crabapples are small to medium size landscape plants, often with Single-flowered crabapple varieties tend trees, ideal for today’s smaller residential more than one season of to bloom earlier than semi- double or lots. Crabapples can be used under power interest. double-flowered varieties. Actual dates of lines, as screens, specimen trees, patio trees, blossoming can vary each year depending wildlife habitat, backgrounds, or grouped • Crabapple trees are generally on weather conditions. The length of the in mass plantings. Smaller or dwarf varieties well-adapted to Colorado blossoming period can range from 1 to can even be planted in containers. Some soils and climate, but varieties 2 weeks, depending on the variety and are budded onto dwarfing apple rootstock or cultivars should be weather conditions. Crabapple flower to make them semi-dwarf or dwarf in size. carefully selected for disease buds are attractive even before they open, There is a crabapple variety to meet just resistance and for higher developing color as they swell—called about any landscape need. Several varieties, elevations. the balloon or bud stage. The balloon may including Dolgo, Radiant, Spring Snow, and be a different color than later flowers. For Thunderchild are hardy to 8000’ elevation example, the balloon may be red-purple (See fact sheet 7.423, Trees and Shrubs for but flowers open later to pink or white. Mountain Areas). Crabapple trees are closely related to There are approximately 1000 different apple trees (also Malus) grown for fruit. The known varieties, of which perhaps 100 are main difference is that crabapple fruit is 2 most commonly planted nationally. These inches diameter or less; fruit greater than vary by mature size, growth habit, flower 2 inches diameter is classified as an apple. color, and the size/color of fruit. About Many crabapples develop showy displays 25 varieties are commonly available and of fruit, increasing their ornamental value planted in Colorado. in the landscape. Some crabapple varieties Plant crabapples in full sun and where have more or longer-lasting ornamental other nearby trees will not shade them value from their fruit display than from excessively. Crabapples flower and fruit their flowers. Fruit varies in size and color, best in full sun, but can tolerate light shade. from 1/4 inch to 2 inches and from yellow Where excessively shaded, crabapples and orange to purple to brilliant red. Some become more open, flower and fruit less, varieties drop fruit upon ripening in fall; and experience more problems with the fruit of many other varieties persists powdery mildew. Planting crabapples on into late winter. Homeowners who recall hot south or west exposures may force ©Colorado State University * them into bloom too early and thus subject J. Klett, Colorado State University Extension landscape Extension. 1/16. horticulture specialist and professor, department of the blooms to late frost damage. horticulture and landscape architecture; and R. Cox, Crabapples are fairly drought-tolerant extension.colostate.edu Arapahoe County Extension horticulture agent. Revised once established, needing only 15 to 20 1/16. receiving drip irrigation or hose-end Powdery mildew is a fungus that looks watering that avoids leaf wetting. like flour or talcum powder sprinkled on Crabapple varieties are usually bud leaves. Affected crabapple leaves may grafted onto one of several different become twisted, narrowed, or otherwise apple rootstocks. As a result, suckering distorted. Avoid excessive shading of at the base is common, more so on crabapples. (See fact sheet 2.902, Powdery some rootstocks than others. It is Mildew, for more information.) important to prune out suckers or use Chlorosis is not a true disease but a ‘sucker- stopper’ product annually. rather a disorder. Usually, newest Planting a crabapple tree too deeply may growth shows leaf yellowing with veins increase the amount of suckering. Left remaining green. This lack of chlorophyll alone, suckers can grow large enough may be caused by alkaline or compacted to become additional trunks on the soils, excessive watering, or excessive crabapple tree, but their flowers may fertilization. Some crabapple varieties are be later and of a different color than more susceptible than others. those of the crabapple. The end result is a multiple-trunk tree that bears both Pests Figure 1: Malus ‘Radiant’ crabapples and apples. Crabapples are fairly strong-wooded Aphids can rapidly develop large and suffer little ice/snow damage. Pruning populations on new growth. (See fact should involve early selection of scaffold sheet 5.511, Aphids on Shade Trees and branches, removal of crossing branches Ornamentals for more information.) and branches originating too close to Borers can be discouraged by keeping each other on the trunk. Depending on crabapples healthy with adequate but not growth habit, lower branches may be excessive moisture and fertility. (See fact removed to allow safe passage under sheet 5.530, Shade Tree Borers.) the tree. Prune out ‘water sprouts’ that Spider mites may become a problem grow straight up and bear few flowers. on leaves of crabapples in hot, dry Pruning can be done before flowering or locations. (See fact sheet 5.507, Spider Mites leafing in late winter/early spring, or after for more information.) blooming. Pruning should be completed by June 1 as flower buds for the following spring are initiated in June-July. Varieties (cultivars) Figure 2: Malus ‘David’ There are several newer dwarf (4 to10 feet) crabapple varieties available Diseases for use in limited-space landscapes or in Fire blight is a bacterial disease that containers. Some of these dwarf varieties results in a blow-torched appearance include Camelot, Cinderella, Guinevere, of leaves. Affected twigs are blackened Lancelot, Lollipop, Madonna and Sargent and may develop a shepherd’s crook. Tina. Many of these are too recent to Fruit looks mummified. There may be have been fully evaluated for disease sunken, discolored, or rough areas on the resistance. trunk. (See fact sheet 2.907, Fire Blight for In the early 1980s, the National additional information.) Crabapple Evaluation Program (NCEP) Apple scab is a fungal disease that was established to rate crabapple results in leaf blotches, leaf yellowing varieties (cultivars) for their ornamental and premature leaf drop. Fruit may value and disease resistance. Colorado develop dark, leathery spots that affect its State University participated in this Figure 3: Malus ‘David’ ornamental value. Avoid leaf wetting and/ nationwide research program. Numerous or plant scab-resistant varieties. varieties that performed well in CSU trials inches of annual moisture (precipitation Rust is a fungal disease known as are included in Table 1 below. plus any supplemental watering). cedar-apple rust or juniper-hawthorn Planting them in high-maintenance rust. Orange, powdery rust spots develop turfgrass generally subjects them to more on the leaf undersides. Leaves drop water and fertilizer than they need, often prematurely. The alternate hosts for this resulting in more incidence of disease. rust are certain types of junipers, where A better location is in mulched beds, the rust appears as a brown-orange gall. Table 1. Available crabapple cultivars adaptable to Colorado’s Front Range. Cultivar or Trade Tree shape; Flower color/ Fruit color/size/ Disease resistance1 Comments name Mature size timing persistent FB AS Ru PM Adirondack inverted 15-20' tall white/mid orange/red R R R R unique upright/spreading growth habit and 8-10' wide 0.5 years Brandywine rounded; double pink-rose/ green/1"/no S S R R fragrant flowers; messy fruit; maroon fall 15-20’ tall and wide late color; exfoliating bark; one of the better double-flowered cultivars Centurion columnar/upright; rose-red / glossy red/0.5"/yes R R R R columnar when young to upright with age; 20' x 15' early yellow fall color Coralburst compact rounded; semi-double none-sparse/-/- R R R R available in tree or shrub form; good patio 12' x 15' pink-rose/mid plant David compact rounded; pink balloon red/0.5"/yes R R R R blooms and fruits heavily in alternate years 12' x 12' white/early Dolgo rounded; white/ red/1.5"/no S S R R large fruit can be