| General Description | Kalmia angustifolia is a short, compact evergreen shrub with pink flowers and green/blue foliage. This shrub has poisonous foliage and is commonly known as lambkill. This plant is very hardy in cold weather. Its flowers and leaves have a whorled arrangement and are densely clustered. This plant has twisted round brown bark. |
| ID Characteristic | This shrub has large clusters of small pink flowers that grow near the end of the branches. It has blue/green foliage, arranged in a whorled pattern, that is highly poisonous. The flowers have five petals that are fused together. The new growth of this plant forms above the flowers. |
| Shape | This shrub can be both spreading or compact and round. This plant has a spreading habit and will grow wider then it will tall. It has multiple twisted stems and opens up as it ages to reveal the stems |
| Landscape | This shrub is used for naturalization of woodlots, and mined peatlands. It can also be used as a landscape plant and would do well in a rock garden, a swampy or damp garden or a garden with acidic soil. This plant is very poisonous and dangerous to animals. This shrub does attract butterflies, moths and bees so it could be used as part of a pollinator garden. This plant makes a good ground cover or understory plant provided it still gets sun. This plant provides good winter interest in the landscape, and makes a good foundation plant |
| Propagation | The plant is propagated primarily through vegetative, asexual means. These plants have an extensive underground rhizome root system and new growth comes out of dormant buds on the root system. The new growth begins in early to mid May. The plants are difficult to germinate by seed. |
| Cultivation | Kalmia angustifolia prefers soils with a pH that is less then 6.8. This shrub prefers cool, wet, boggy soil with high organic matter content, it will also grow in dry soils provided they are not too basic. Many people believe this shrub to be shade tolerant, and while it will grow in shade it prefers full sun to partial shade. The plant will grow in full shade but will be thin, sparse, and not produce many blooms. This plant is very hardy and can handle extreme cold. It does not enjoy wind and prefers protected areas. |
| Pests | Kalmia angustifolia is attractive to lacebugs, leaf spot, and leaf scorch. The leaf scorch is more of an issue when the plant is not in wind protected location (Dirr, 2009). Lacebugs are a common pest as well (Kalmia, n.d.A). Leaf spot is common, only when the plant is in shade for too long, which is why it is important to keep the plant in full sun to partial shade. Most of these pests are not very common and do not cause many issues that are deadly to the plant. This plant is not deer resistant which could be an issue. |
| Notable Specimens | Kalmia angustifolia can be found along the John Brown Trails in Lake Placid, New York in the United States of America. |
| Habitat | Kalmia angustifolia grows naturally in bogs and wetland areas. This plant is also commonly found in blueberry fields. This shrub is also at home in hardwood and coniferous forests. Kalmia angustifolia can poison the ground around it making it difficult, particularly for coniferous trees to grow.
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| Bark/Stem Description | The bark and stems are described as twisty, round, and brown. The branches are often revealed more as the plant ages and spreads and are also described as “gnarled”. The new growth is described as green and thin, becoming brown and scaly bark as it ages |
| Flower/Leaf Bud Description | Leaf buds for the next season grow above the previous season’s flowers. The lateral leaf buds are small with two over lapping scales. The flower buds are oblong, with bumps along the bud which are the anthers inside the bud. |
| Leaf Description | The leaves on Kalmia angustifolia are simple and elliptic. They are arranged in groups of 3 in a whorled pattern. The leaves are 2.-5 cm long, 0.5-2 cm wide and have pinnate venation. The leaves have entire margins with rounded and slightly tapered bases. They are blue/green in colour, turning slightly red/brown in the fall. They have a waxy coating on top and bloom on the bottom side. The leaves are attached to petioles that are about 1 cm long. The leaves are described as flat and firm. |
| Flower Description | The flowers are pink/purple in colour and small. The flowers are saucer-shaped, with ten stamens that are fused to the petals. The flowers are 6-13 mm wide. The anthers of the flowers are purple to brown. The flowers have a red ring around the ovary at the base of the corolla. The flowers bisexual and can self pollinate but do better when there is cross pollination. The flowers grow in lateral clusters with many flowers and are arranged around the stem while growing just above last years leaf axis. The calyx is green or red/brown in colour and has a bit of fine hair on it. Kalmia angustifolia flowers from mid-June to early July. These flowers are pollinated primarily by bees. |
| Fruit Description | The fruit is small and woody, only about 3-5 mm wide and 2-3 mm long. Mature capsules are brown, immature capsules are green or brown with a red tinge. The fruit is spherical and indented on the top. The fruit has 5 segments. The capsules are formed mid-September hold many seeds which are spread by the wind when the capsules open in October. |
| Colour Description | The colour of Kalmia angustifolia’s foliage is blue/green and changes to red/brown in the fall. The bark is brown to reddish brown when matured and new growth is green with fine hairs. The fruit is brown when it is mature and green when it is immature. The bloom is pink, with purple to brown anthers and a red ring around the middle of the bloom which surrounds the ovary. |
| Texture Description | The bark of Kalmia angustifolia is smooth when it is young but as it ages it becomes scaly. The leaves remain smooth throughout the life of the plant. |