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Publication #ENH-562

Malus x zumi 'Calocarpa': Redbud Crabapple1

Edward F. Gilman and Dennis G. Watson2

Introduction

A hybrid of Malus baccata and Malus seiboldii, redbud crabapple grows at a moderate rate to 25 feet tall and 15 feet wide (can grow 30 feet wide), creating a dense, pyramidal form with weeping branch tips. True to its name, the blossoms of redbud crabapple start out as red buds in spring which open to soft pink flowers, eventually fading to white. These blooms are delightfully fragrant and open in spring before the new leaves appear. The small, shiny, bright orange/red fruits that follow, persist on the tree well into the winter, if not first eaten by birds.

Figure 1. 

Young Malus x zumi 'Calocarpa': Redbud Crabapple


Credit:

Ed Gilman, UF/IFAS


[Click thumbnail to enlarge.]

General Information

Scientific name: Malus x zumi
Pronunciation: MAY-lus x ZOO-mee
Common name(s): Redbud crabapple, 'Calocarpa' zumi crabapple
Family: Rosaceae
USDA hardiness zones: 4A through 8A (Fig. 2)
Origin: not native to North America
Invasive potential: little invasive potential
Uses: espalier; street without sidewalk; tree lawn 3-4 feet wide; tree lawn 4-6 feet wide; tree lawn > 6 ft wide; deck or patio; trained as a standard; container or planter; parking lot island > 200 sq ft; parking lot island 100-200 sq ft; parking lot island < 100 sq ft; highway median
Availability: not native to North America

Figure 2. 

Range


[Click thumbnail to enlarge.]

Description

Height: 20 to 25 feet
Spread: 15 to 30 feet
Crown uniformity: irregular
Crown shape: spreading
Crown density: dense
Growth rate: moderate
Texture: medium

Foliage

Leaf arrangement: alternate (Fig. 3)
Leaf type: simple
Leaf margin: serrate, serrulate, crenate
Leaf shape: elliptic (oval)
Leaf venation: pinnate, brachidodrome
Leaf type and persistence: deciduous
Leaf blade length: 2 to 4 inches
Leaf color: green
Fall color: yellow
Fall characteristic: not showy

Figure 3. 

Foliage


[Click thumbnail to enlarge.]

Flower

Flower color: white/cream/gray, pink
Flower characteristics: very showy

Fruit

Fruit shape: round
Fruit length: less than .5 inch
Fruit covering: fleshy
Fruit color: red, orange
Fruit characteristics: attracts birds; showy; fruit/leaves not a litter problem

Trunk and Branches

Trunk/bark/branches: branches droop; not showy; typically multi-trunked; thorns
Pruning requirement: needed for strong structure
Breakage: resistant
Current year twig color: brown
Current year twig thickness: thin, medium
Wood specific gravity: unknown

Culture

Light requirement: full sun
Soil tolerances: clay; sand; loam; acidic; alkaline; well-drained; occasionally wet
Drought tolerance: moderate
Aerosol salt tolerance: low

Other

Roots: not a problem
Winter interest: yes
Outstanding tree: yes
Ozone sensitivity: unknown
Verticillium wilt susceptibility: resistant
Pest resistance: resistant to pests/diseases

Use and Management

This has been described as one of the best crabapples for street tree planting. When specifying trees for street or parking lot planting, be sure to order single trunked trees with major branches located as high on the trunk as possible. This will reduce the need to prune off lower limbs to provide clearance for vehicles and pedestrians. However, branches will still need to be removed as the tree grows older due to the slightly drooping habit of the tree. Suckers from the root system may also need to be occasionally removed. Trees planted away from walks and streets can be pruned and trained any way you like. They often look nice with branches left to the ground, forming a solid, thick, mounding shape with age.

Redbud crabapple should be grown in full sun on well-drained, acid soil. They are adapted to a variety of soils, including clays. It is recommended that you purchase trees propagated on their own roots.

Pests

No pests are of major concern. Aphids can usually be found infesting a variety of crabapples, including this one. Control of pests is usually not needed.

Diseases

Although resistant to scab, redbud crabapple is susceptible to fireblight and mildew.

Footnotes

1.

This document is ENH-562, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date November 1993. Revised December 2006. Reviewed February 2014. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Edward F. Gilman, professor, Environmental Horticulture Department; Dennis G. Watson, former associate professor, Agricultural Engineering Department, UF/IFAS Extension, Gainesville FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.