Mountain Laurel, A Native Shrub to Love
Mountain Laurel, Kalmia latifolia
I love finding mountain laurel growing in large, lovely masses in the wild. Its creamy pink flowers glow softly in the forest. Wild mountain laurel, Kalmia latifolia, sometimes grows along the undeveloped banks of creeks and rivers in Eastern Virginia. It grows as an understory shrub in our oak, beach and pine forests.
These evergreen shrubs, almost small trees, simply blend into the fabric of the woods through much of the year before bursting into bloom, suddenly elegant and beautiful, in late April and early May. The native species mountain laurel has flowers of white or pink. Some cultivars in the nursery trade have been selected for darker flowers of red or maroon. Ours probably pre-dates our neighborhood, from when this forested land was still undeveloped.
Mountain laurel grows best in moist acidic soils in bright shade.
An Early Horticultural Export
Early American botanists first recorded mountain laurel, then called “Spoonwood,” in 1624. Carl Linnaeus named the shrub for Pehr Kalm, a Swede, who explored eastern North America in search of new and useful plants in 1748-49. Mountain laurel, one of the most ornamental native plants growing along the eastern coast of North America, was one of the plants Kalm collected to export to gardeners in Europe.
Mountain laurel grows from Maine all the way to Florida in Zones 5-9. It even grows along the Gulf Coast from western Florida to eastern Louisiana. But it isn’t generally found near the Atlantic coast south of Virginia. It prefers the coolness of the mountains. Its southern range moves ever further west, at elevation, following the Blue Ridge and Appalachian Mountains.
Mountain laurel, part of the Ericacea family of plants, is related more closely to blueberries than to bay laurel, which is native to Europe. It prefers moist, acidic soil and requires at least partial shade. Although the shrubs flower more abundantly in bright shade than deep, Kalmia don’t like growing in full sun. These plants are best mulched, and fertilized, with pine straw or pine bark mulch.
Mountain Laurel is Poisonous
All parts of the mountain laurel shrub are poisonous, from root to nectar. They have survived in our garden over the years because the deer rarely graze them. Even honey made from Kalmia flowers in bitter and toxic for human consumption, although it will sustain a hive of bees. Native bees, and other pollinators, gather nectar and pollen from mountain laurel when it blooms each spring.
Growth Habit
These shrubs don’t need pruning. They are best left to grow in their own twisted, idiosyncratic way. Over time they form a thicket. Their open structure near the ground offers intriguing little places in the garden for birds and small animals to seek shelter. Underplant these shrubs with evergreen Christmas ferns as an evergreen, carbon sequestering ground cover layer. Kalmia wood is very hard and brittle, much like the wood of Rhododendrons, close relatives also in the Ericaceae family. Although they can get very tall over many years in optimal conditions, most Kalmia won’t grow more than 15′-20′ tall in one’s garden. The largest specimens usually grow in the Appalachian Mountains on steep embankments.
Propagation and Culture
Mountain laurel can be started from cuttings taken from young plants in early fall, but plants should never be dug from the wild. Dust-like seeds should be sown fresh. Commercial production is from tissue culture and shrubs can be ordered from several online nurseries. Sometimes they can be purchased at nurseries in regions where they will grow. Plant mountain laurel a little “high” like an azalea, as planting too deeply may kill the shrub.
Mountain Laurel will grow successfully if you can site them in the moist, shady, acidic forest environment they prefer. Kalmia may be grown alongside dogwood trees, native blueberries, azaleas, native hollies, and of course, pines, oaks, beech, and other native hardwood trees. Their roots like to remain cool and moist, so it is important to keep the shrubs mulched. Water the first few seasons as the shrubs are established, and then only in times of drought.
A little careful planning and initial care will reward you with many years of beauty as mountain laurel grows into its potential. It is beautiful throughout the seasons, but especially when it is covered in flowers in late spring.
All Photos by Elizabeth McCoy, Master Gardener Tree Steward
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