SCIENTIFIC NAME: Malus spp.
This tree in Colorado Crabapple trees show their beauty in Colorado’s urban and community landscapes at this time of the year. Despite the cold and damp weather we’ve experienced, our streets, yards and parks were colorful because of the multitude of crabapple varieties that are planted. May’s Feature Tree is dedicated to this tree that leads us into the season of planting. There are over 700 recorded types of crabapples with about 200 grown in North America. New types are propagated regularly so it is difficult to keep an accurate registry of them. The Department of Horticulture at Colorado State University is doing a study on 60 different varieties. Dr. James Klett has been studying their characteristics since 1986.
Hardiness Crabapples are not native to Colorado. They have a wide range of adaptability, probably Zone 2 or higher. They are found in many of Colorado’s higher elevation communities.
Growth rate Medium to fast growing. Height varies depending on species and variety. They are considered a small tree that reaches a mature height of 15′ to 25′.
Flowers White to pink or carmine to red to rose. Single flowers have 5 petals. They bloom in early spring and usually last three or four weeks between mid April and mid May. The blooming period is earlier at lower elevations or later in the higher elevation communities. Common white blossom crabapple varieties are: David, Dolgo, Spring Snow, Snowdrift, White Angel.
Insects and diseases Fire blight is the main disease that affects crab apples. Studies from Colorado State University indicate that the fireblight prone varieties are: Dolgo, Mary Potter, Ormiston Roy, Red Barron, Red Jade, Royalty, Sentinel, Silver Moon, and Strawberry Parfait. Those that currently show resistance to fire blight are: Centurion, David, Indian Summer, Molten Lava, Profusion, and Robinson. Cedar apple rust is another disease that affects crabapples. Crabapples leaves get yellow or orange spots which can cause early and heavy leaf drop. The alternate host of this disease is the Juniper species. The best cultural control is to separate these plants by 500 feet or so.
Landscape value Because of its small size and colorful flowers and leaves, this plant is often used to accent front yards and specific areas in back yards or open spaces. Planting in groups of three or more makes a major visual impact while in bloom. Many develop a fruit which can be messy later in the year so chose a variety that is less messy for areas around sidewalks and other high use areas.
Best advice Study which crabapples are commonly grown in your area. Purchase varieties of crabapples that are resistant to fire blight, a bacterial disease that affects the tips of young shoots and bud clusters. Plant in areas that receive full sunlight. Remember that most crabapples have fruit that can create a mess later in the year, especially along sidewalks and driveways.
Michael Dirr, Manual of Woody Landscape Plants (University of Georgia, 1990)