This is a large shrub or small tree about 15-30' tall
that forms a
single short trunk and a relatively broad crown. Trunk bark is dark
gray, irregularly furrowed with flat ridges, and coarsely textured.
Branch bark is light gray to gray-brown and more smooth with scattered
Twigs are brown, grayish brown, or purplish brown; they are also terete
and smooth with scattered lenticels. Young shoots are light green,
short-pubescent, and terete. Alternate leaves occur along the twigs and
young shoots. These leaves are 1½-3½" long and ¾-2" across; they are
ovate or broadly elliptic and finely serrated along their margins. The
teeth of the margins may be blunt or sharp. The upper leaf surface is
medium green and glabrous, while the lower leaf surface is light green
and sparsely short-pubescent, especially along the major veins. Very
young leaves tend to be more hairy. The petioles are ½-2¼" long, light
green, and sparsely short-pubescent to nearly glabrous.
Corymbs of 3-10 flowers are produced near the axils of the leaves on
spur-shoots. The flowers are pinkish in bud, but become white when they
bloom. Each flower is 1½-2" across, consisting of 5 white petals, 5
light green sepals that are joined together at the base, about 20
stamens with pale yellow anthers, 4-5 styles, and an inferior
ovary. The sepals are about 1/3" (8 mm.) in length,
lanceolate-triangular in shape, and short-pubescent along their outer
surfaces. After the blooming period, withered remnants of the sepals
persist on each pome. The floppy pedicels are ¾-2" long, light green to
pale red, and sparsely short-pubescent to nearly glabrous. The
blooming period occurs during mid- to late-spring for about 2 weeks.
Afterwards, the flowers are replaced by fruits that are referred to as
'pomes.' At maturity during late summer or autumn, these pomes are ¾-1"
across, more or less globoid in shape, glabrous, and usually bright red
(or less often yellow). Each pome has a slight depression where it is
joined by the petiole, while its opposite end near the withered sepals
either a slight depression or such a depression is lacking (often the
interior of the pome contains firm white flesh and about 8-10 seeds. No
vegetative offsets are produced from the woody root system; this crab
apple reproduces by reseeding itself.
Crab Apple adapts to full or partial sun, moist to dry-mesic
conditions, and a variety of soil types, including loam,
clay-loam, silty loam, and sandy loam. It is vulnerable to a variety of
disease organisms that can affect the leaves or fruit.
The introduced Plum-Leaved Crab Apple
has naturalized in
Kane County and Champaign County (see Distribution
has rarely escaped from cultivation in Illinois, although available
records may underestimate its occurrence. Plum-Leaved Crab Apple is
native to parts of East Asia, including northern China. Typical
include overgrown shrubby areas, riverbanks, and fence rows. While this
species is rarely cultivated anymore in its original form, it is still
used as grafting stock for various apple cultivars.
Crab apples (Malus spp.
a variety of
wildlife. Their flowers are cross-pollinated
primarily by bees, including Andrenid bees (Andrena spp.
and bumblebees. Both nectar and pollen are available as floral rewards.
The larvae of some beetles bore through the wood of crab apples; they
(Flat-Headed Apple Tree
Borer), Saperda candida
(Round-Headed Apple Tree Borer), and Amphicerus
(Apple Twig Borer). Other insects suck juices
leaves, young shoots, inner bark, or roots; they include Aphis pomi
(Green Apple Aphid), Dysaphis
(Woolly Apple Aphid), Typhlocyba
(White Apple Leafhopper), Ceresa bubalus
(Buffalo Treehopper), and
(Oystershell Scale). The white larvae of a fruit fly,
(Apple Maggot), develop in the fruit of crab apples. Other insect
feeders include the caterpillars of such
moths as Balsa malana
(Eastern Tent Caterpillar), Phyllonorycter
Blotch Leaf-Miner), and Cydia
(Codling Moth); the Moth Table
more complete list of these
In addition, caterpillars of the
(Tiger Swallowtail) occasionally feed on the leaves.
Vertebrate animals use crab apple trees as a source of shelter and
food. The fruit is eaten by such mammals as the Black Bear, Red Fox,
Gray Fox, Coyote, Opossum, Raccoon, Gray Squirrel, Fox Squirrel,
Striped Skunk, Deer Mouse, and Pine Mouse. White-Tailed Deer
browse on the leafy twigs and the Cottontail Rabbit gnaws on the bark
of saplings (Barnes, 1999; Martin et al., 1952/1962). Although the
fruits of Plum-Leaved Crab Apple are somewhat large to be carried about
by birds, they are still pecked at and occasionally eaten by various
upland gamebirds and songbirds (see Bird Table
Because of the dense
branching structure of these shrubs or small trees, they provide good
nesting habitat for the Song Sparrow, Orchard Oriole, Yellow-Breasted
Chat, and other songbirds.
A shrubby area of Busey Woods in Urbana,
Because so many cultivars of crab apples (Malus spp.
ornamental shrubs or trees, naturalized specimens of crab apples are
often difficult to identify as some hybridization across different
species is common. Plum-Leaved Crab Apple can be identified by its
relatively robust size, the characteristics of its leaves, and the
characteristics of its fruits. For example, the leaves of Plum-Leaved
Crab Apple are more hairy than those of Siberian Crab Apple (Malus
) and less hairy than those of the cultivated Apple
). Its leaves also lack the lobes that are common on
of native crab apples in Illinois (Malus
). The fruits of Plum-Leaved Crab Apple are larger
in size than
those of Siberian Crab Apple, but they are smaller in size than those
of the cultivated Apple. While the fruits of Plum-Leaved Crab Apple are
usually red, the fruits of native crab apples in Illinois are usually
greenish yellow. Because of its intermediate characteristics, some
authorities have proposed that Plum-Leaved Crab Apple may be a
naturally occurring hybrid between the Siberian Crab Apple and the
cultivated Apple. However, it is currently classified as a distinct
species in most taxonomies.