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Calico Bush

Kalmia latifolia (KAL-mee-ah lah-tih-FOH-lee-ah)

Family: Ericaceae Native Understory (15-40 ft)

Mountain laurel is a broadleaf, evergreen shrub or small tree in the blueberry family (Ericaceae) native to eastern North America, where it is found in a variety of habitats, including open rocky or sandy woods, meadows, balds, mountain slopes, acidic forests and woodland margins. Linnaeus named the genus after Swedish botanist Peter Kalm (1716–1779), who botanized in eastern North America from 1747 to 1751. The species epithet is Latin for “broad leaf.” Mountain laurel tolerates a wide range of light conditions, from full sun to full shade, but grows best in partial shade (morning sun with early to mid-afternoon shade) and in cool, moist, acidic, humus-rich, well-drained soils. Mulch to retain moisture and keep root zones cool. The plant does not grow well in heavy clay soils or wet soils. In heavy soils, raised plantings should be considered to promote better drainage. Remove spent flower clusters immediately after bloom and prune branches back lightly after bloom to promote bushy growth. When pruning, keep in mind that next year's blossoms will appear on old growth. It can grow slowly to 6 to 10 feet tall as a dense, rounded shrub, opening up and developing gnarly branches with age. It will rarely grow to 32 feet tall as a small tree, particularly on slopes in the Appalachian Mountains. It blooms in late spring to early summer, and its buds and fruits are showy. Attractive foliage makes this a good choice for year-round interest. Flowers have touch-sensitive anthers contained in pockets in the corolla. When triggered by a bee, the filaments spring out of their pockets in the corolla and dust the bee with pollen. There are many cultivars available, including some that are heat-tolerant and even some that are dwarf varieties. Plant mountain laurel in a meadow, naturalized or woodland area, and use it as an accent or flowering shrub in a native, children’s, butterfly or pollinator garden. Fire Risk: This plant has a high flammability rating and should not be planted within the defensible space of your home. Select plants with a low flammability rating for the sites nearest your home. Quick ID Hints: Evergreen shrub with sympodial growth and elliptic leaves Fruit, buds, or inflorescence are visible year-round Terminal clusters of bell-shaped flowers are present in the late spring Flowers have inner purple markings and 10 anther pockets Old trunks and limbs are gnarly, cracked, and crooked Insects, Diseases, and Other Plant Problems: Mountain laurel is susceptible to borers, scale, white fly, and lace bugs. It is also susceptible to leaf spots and blights. While the nectar poses no problems for bees, if honey bees feed heavily on these plants, they are known to produce honey that may be toxic for humans.

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 72 attributes.

How it fits the guild

Guild layer 2 - Understory (15-40 ft) Optimal soil pH Acid (<6.0)
See companions & conflicts ↓

Companions & Conflicts

Curated pairwise relationships between this plant and others in the library — who feeds whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.

No curated interactions recorded for this species yet.

Also noted by NC State

Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.

Full plant profile

Growing Conditions
Plant type
Native Plant; Perennial; Poisonous; Shrub
Life cycle
Perennial; Woody
USDA zones
4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Light
Dappled Sunlight (Shade through upper canopy all day) | Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
High Organic Matter; Loam (Silt); Sand; Shallow Rocky
Soil pH
Acid (<6.0)
Soil drainage
Good Drainage | Moist | Occasionally Dry
Available space
6-feet-12 feet; 12-24 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 4 ft. 0 in. - 15 ft. 0 in. | Width: 4 ft. 0 in. - 8 ft. 0 in.
Canopy layer
2 - Understory (15-40 ft)
Form & Appearance
Habit / form
Dense; Multi-stemmed; Open; Rounded
Texture
Medium
Foliage
Broadleaf Evergreen
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate; Opposite; Whorled
Leaf shape
Elliptical; Lanceolate; Oblanceolate
Leaf feel
Glossy; Leathery
Leaf value
Long-lasting; Showy
Leaf size
3-6 inches long, < 1 inch wide
Hairs present
No
Leaf detail
The mountain laurel has elliptic to lanceolate or oblanceolate, simple, alternate, acute to short acuminate, cuneate, coriacious, entire, leathery, and congested glossy evergreen leaves (2 to 5 inches long) which are dark green above and yellow-green beneath and reminiscent of the leaves of rhododendrons. The leaves are occasionally opposite or whorled. New growth is yellow-green.
Flower color
Pink; Purple/Lavender; White
Flower value
Showy
Flower form
Corymb
Flower shape
Cup; Saucer
Flower size
< 1 inch
Flower detail
Flowers appear in terminal clusters (corymbs 4 to 6 inches in diameter), typically covering the shrub in late April-July for several weeks. Each flower (to 1 inch across) is cup-shaped with five sides, and ranges in color from rose to white with purple-red markings inside the corolla. The corolla holds 10 anthers on recurved filaments. Pollinators trigger the flowers and cause the filaments to spring toward the center, striking the pollinators with pollen. Once triggered, the flower cannot fire again.
Bloom time
Spring; Summer
Fruit color
Brown/Copper
Fruit type
Capsule
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
The plant produces 5-valved, dehiscent capsules (3/16 inch) that are non-showy and brown in color and persist into winter. Fruits are available from September to October.
Bark detail
The bark is thin, smooth and dark red-brown in color in young trees. The barks shreds and splits as the tree ages. The trunk is contorted with cinnamon bark.
Stem color
Brown/Copper; Green; Red/Burgundy
Stem detail
Stems are sympodial and initially bronze and sticky. As they mature, they turn turn red green or brown and become crooked and gnarly. Epidermis and gray-brown bark crack to reveal lighter colors in older stems. Pith is solid and light green.
Wildlife & Ecology
Native status
Native
Origin
Eastern U.S.A
Distribution
New England south to the southern Indiana, Louisiana and the Florida panhandle
Wildlife value
It provides winter cover. Hummingbirds, butterflies and other pollinators are attracted to the flowers. Although the foilage is toxic to domestic livestock, white-tailed deer browse the leaves and twigs during the winter and early spring.
Attracts
Butterflies; Hummingbirds; Pollinators; Small Mammals
Play value
Colorful; Wildlife Cover/Habitat; Wildlife Food Source
Food & Medicine
Harvest time
Fall
Fruit type
Capsule

Uses (ethnobotany)

The leaves were once used to create infusions, liniments and salves to treat bruises, cuts, rheumatism and pain. The wood is useful for carving.

Landscape Use
Landscape location
Coastal; Meadow; Naturalized Area; Recreational Play Area; Woodland
Landscape theme
Butterfly Garden; Children's Garden; Native Garden; Pollinator Garden
Design feature
Accent; Flowering Tree; Shade Tree
Garden tags
#contorted trunk #poisonous #hummingbird friendly #evergreen #dwarf #interesting bark #children's garden #fire high flammability #naturalizes #native garden #fantz #NC native #native shrub #butterfly friendly #Piedmont Mountains FACU #food source herbage #Coastal FACU #food source nectar #mammals #food source pollen #pollinator plant #problem for dogs #problem for horses #problem for cats #bird friendly #Audubon #nectar plant early summer #nectar plant late spring #nectar plant mid-spring #food source hard mast fruit #flowers late spring #flowers early summer #deer browsing plant #poisonous nectar #playground plant #flowers mid-spring #wildlife friendly #cpp #HS304 #winter cover
Problems & Resistance
Insect problems
Lace Bugs; Bandedwinged Whitefly on Ornamentals; Wood Boring Beetles in Trees; Armored Scale Identification and Management on Ornamental Plants
Problems
Poisonous to Humans; Problem for Cats; Problem for Dogs; Problem for Horses
Resistant to
Compaction; Deer
Particularly resistant to
Highly resistant to damage from deer.
Fire risk
high flammability
Poison severity
High
Poison parts
Bark; Flowers; Fruits; Leaves; Roots; Seeds; Stems
Poison symptoms
The toxic principle interferes with normal skeletal muscle, cardiac muscle, and nerve function. Clinical effects typically occur within a few hours after ingestion, and can include acute digestive upset, excessive drooling, loss of appetite, frequent bowel movements/diarrhea, colic, sweating, abdominal pain, depression, weakness, loss of coordination, stupor, watering of eyes and nose, nausea, cardiac failure, vomiting, leg paralysis, weak heart rate, and recumbency for 2 or more days; at this point, improvement may be seen or the animal may become comatose and die. Typically not very palatable to horses unless it is the only forage available, but sheep and goats may graze readily on the plant.
Toxic principle
Andromedotoxin, a resinoid; arbutin, a glycoside, Grayanotoxins
Contact dermatitis
No
Toxicity summary
High severity poison; parts: Bark; Flowers; Fruits; Leaves; Roots; Seeds; Stems

Planted at Hunnicutt

Nobody’s planted this one yet.