Kalmia latifolia, mountain laurel
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Broadleaf Evergreen Shrubs

Kalmia latifolia

mountain laurel

Ericaceae

Eastern North America, from southern Maine and southern Ontario south to Florida panhandle and west to Louisiana; most abundant in the southern Appalachian Mountains

At a Glance

TypeShrub
HabitMounding
FoliageEvergreen
Height5-15 feet (1.5-4.5 m)
Width5-15 feet (1.5-4.5 m)
Maturity15 years

Growing Zones

USDA Hardiness Zones

4 - 9
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8
Zone 9
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy

Key Features

Attracts Pollinators
Attracts Butterflies
Deer Resistant
Native to North America
Maintenancemoderate

Overview

A broad-leaved evergreen shrub reaching 5-15 feet (1.5-4.5 m) tall with a similar spread in its native habitat, though typically 4-8 feet (1.2-2.4 m) in cultivation. Growth rate is slow, adding 4-8 inches (10-20 cm) per year; plants may take 10-15 years to reach mature landscape size. Leaves are alternate, elliptical to lance-shaped, 2-5 inches (5-13 cm) long and 1-1.5 inches (2.5-4 cm) wide, leathery, glossy dark green above and yellowish-green beneath, persisting 2-3 years before dropping. New growth emerges light green in spring. Flower buds form in terminal clusters of 50-200 buds, appearing as angular, ridged structures through winter. Flowers are cup-shaped, 0.75-1 inch (2-2.5 cm) across, ranging from white to pink to rose with purple markings inside, opening from crimped buds in late May through June. Each flower contains 10 stamens held under tension in small pockets of the corolla; when triggered by pollinators, the stamens spring inward to dust the visitor with pollen. Fruit is a small brown capsule persisting through winter. Bark is reddish-brown, furrowed on older specimens. Lower branches may die out in dense shade, creating an open, irregular form. All parts of the plant contain grayanotoxins.

Native Range

Native to eastern North America from southern Maine and southern Ontario south to the Florida panhandle and west to Louisiana. Occurs in acidic, rocky or sandy woodlands, mountain slopes, and stream banks from sea level to approximately 4,500 feet (1,370 m) elevation in the Appalachian Mountains. Most abundant in the southern Appalachian region where it forms dense thickets in the understory of oak-hickory and mixed hardwood forests.

Suggested Uses

Commonly planted in woodland gardens, foundation plantings on north- or east-facing exposures, and as understory shrubs beneath high-canopied deciduous trees at 4-6 foot (1.2-1.8 m) spacing. Mass plantings create dense evergreen screening in shaded areas. Not suitable for containers long-term due to size and shallow root system requirements.

How to Identify

Distinguished by its glossy, leathery, elliptical evergreen leaves, 2-5 inches (5-13 cm) long, arranged alternately on the stems. Flower buds are angular and ridged, resembling small geometric pastries. Open flowers are cup-shaped with a distinctive ring of 10 small pockets around the inner surface, each holding a bent stamen. Bark on mature stems is reddish-brown and furrowed, distinguishing it from Rhododendron species which have smoother bark.

Appearance

Size & Dimensions

Height5' - 15'
Width/Spread5' - 15'

Reaches mature size in approximately 15 years

Colors

Flower Colors

white
pink
rose

Foliage Colors

green

Bloom Information

Bloom Period

~3 weeks
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Spring
Late May through mid-June in zones 5-7; early to mid-May in zones 8-9. Individual flowers last 1-2 weeks; total bloom period extends 2-4 weeks depending on temperature. Cool spring temperatures prolong bloom; temperatures above 85°F (29°C) shorten flower display. Flower buds are set the previous summer, so late spring frosts may damage buds and reduce bloom in exposed locations.

Detailed Descriptions

Flower Description

White to pink to rose with purple markings

Foliage Description

Glossy dark green above, yellowish-green beneath

Growing Conditions

Sun Requirements

Partial Shade
Requires 3-6 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range4.5 - 6.0(Acidic)
357912
Soil Types
loamsand
Drainage
well drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

10-15 years

Care & Maintenance

Care Guide

Plant in acidic soil (pH 4.5-6.0) amended with organic matter; chlorosis develops in alkaline conditions. Water deeply every 7-10 days during the first two growing seasons and during prolonged drought. Established plants tolerate moderate drought but leaf margins brown and curl when stressed. Apply 2-3 inches (5-8 cm) of acidic mulch (pine needles or shredded oak leaves) extending to the drip line, keeping mulch 3 inches (8 cm) from the trunk. Do not cultivate around plants, as roots are shallow and fibrous. Leaf spot (Mycosphaerella) and lace bug damage occur in stressed plants, particularly those in full sun with reflected heat.

Pruning

Remove spent flower clusters (deadhead) immediately after bloom to redirect energy from seed production to vegetative and flower bud growth for the following year. Rejuvenation pruning, cutting stems back to 6-12 inches (15-30 cm) above ground, can be performed in late winter on overgrown plants; regrowth is slow, requiring 3-5 years to resume flowering. Light shaping cuts should be made just after flowering. Remove dead or crossing branches in late winter before new growth begins.

Pruning Schedule

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summerwinter

Maintenance Level

moderate

⚠️ Toxicity Warning

Toxic to pets and humans