Expert guide

Mountain Laurels

Kalmia

Hating waterlogged clay and lime; the Kalmias prefer and thrive on moist, light, slightly acid, WELL DRAINED soil in the cool, moist dappled shade under trees. They prefer the shade of coniferous trees such as Hemlock as full sun during winter can damage the foliage. Mulch lightly with leaf humus or shredded hardwood mulch to keep soil cool and moist. Mixing peat moss into the entire planting bed will improve establishment and growth. The fine roots on Kalmia may be unable to penetrate compacted soils or heavy clay. Fertilizing with Holly-tone during early spring, late spring, around July 1 and mid-autumn will also improve growth. During drought, it is recommended to water plants deeply once every week to 2 weeks, rather than frequently.
Little pruning is needed other than removing old flower heads to speed up and improve growth. Other pruning can be done during early spring if required. A well pruned plant will be more compact and dense than if left alone.
For reproducing; the seed should be collected immediately upon ripening in autumn and planted the following spring.
Layering is easy; you just set it down in the autumn then cut and separate the offspring a year later. Tip cuttings can be done in late summer but are difficult to root.
Transplanting should be done during autumn or spring before growth begins. The plant should be planted around 3 inches above grade sloping to base soil level at around 18 inches away with no turf / groundcover root competition within that area. Root growth on Kalmia is more vigorous during autumn. Never pick up a Kalmia by the stem as this can severely injure the root system. Always grab it by the container or below the roots.
The Kalmias are deer resistant! They should not be eaten by people either - they are not edible.
The species and some cultivars are prone to leaf spot while other cultivars are immune. Blight, scale, lacebug and borers may sometimes occur, however Kalmias are usually easy to grow if soil is acidic and well drained.

Kalmia angustifolia ( Sheep Laurel )
A dwarf, dense, bushy, mounding, upright shrub native to acidic bogs in northeast North America ( from Ontario to Labrador and Newfoundland, south to Michigan to Virginia & North Carolina ).
It is a slow growing, spreading dense bush to 3 feet or very rarely 6.5 x 6 feet. The Sheep Laurel is a very beautiful plant which should be utilized where adapted.
The oblong leaves, up to 3 ( rarely over 2 ) inches in length, are smooth, glossy deep green.
The rosy-red, saucer-shaped flowers, up to 0.5 inches across, are borne in dense clusters, up to 2 inches across, during early summer.
Pharmacology: entire plant is poisonous.
Hardy zones 1 to 7 in full sun to partial shade on sandy or peaty, acidic soil.
Propagation is from seed sown during autumn. Cultivars can be propagated from softwood cuttings taken during summer.

Candida
white flowers, otherwise identical.

subsp Carolina
Foliage is downy beneath and the flowers are deep red.

Purpurflora
Upright in habit, reaching up to 2.5 feet in height.
The linear leaves, up to 0.2 inches in length, are gray-green.
The flowers, up to 0.4 inches across, are deep purplish-red.

Rubra
Pink-red flowers with a long bloom period.

Stodge Meadow
Upright in habit, reaching up to 3 feet in height.
The very profuse flowers are reddish-pink.

Kalmia hirsuta ( Sandhill Laurel )
Also called K. ciliata. An attractive small, evergreen shrub, reaching up to 2 feet in height, that is native to pine woods, pine-savanna and sand dunes in the southeast U.S. ( from southern Alabama to southeastern South Carolina; south to central Florida ).
The alternately-arranged, ovate to elliptical leaves, up to 0.5 inches in length, are hairy and gray-green.
Hardy zones 8 to 9 in full sun on very well drained soil.

Kalmia latifolia ( Mountain Laurel, Calico Bush )
Native to oak & pine forests of eastern North America, especially to the Appalatian Mountains and the Northeast.
It is often a dense bushy rounded large shrub around 10 feet but on ideal sites can also grow into s small tree reaching up to 20 x 20 feet in 20 years. Rarely larger; the largest trees ever recorded reach up to 50 x 20 feet with a massive trunk diameter up to 4 feet. Long lived up to 100 years or more.
The elliptic evergreen foliage is up to 4 or rarely 6 x 3.5 inches in size and smooth dark green above & paler below.
The flowers, up to 1 inch across, are typically pink in terminal clusters, up to 6 inches across. They typically bloom for a 2 to 4 week period during late spring into early summer ( unless otherwise noted on cultivars below ).
Hardy zones 3 to 9 in partial shade, preferring fertile, light, sandy, acid soil. Pruning not recomended - plants regenerate very slowly when cut back.
Propagation is by seed in autumn and by softwood cuttings in summer. Layering in fall also works. Is also commonly planted in the British Isles.

* photos taken on May 22 in Ellicott City, MD




This massive beauty is growing behind the Asian Gardens at the U.S. National Arboretum in DC



* photos taken on May 8 2010 @ U.S. National Arboretum, D.C.


* photo taken on May 1 2010 @ U.S. National Arboretum, D.C.

* photos taken on June 7 2012 in Columbia, MD
* photo taken on Mar 7 2013 in Wheaton, MD


Big Boy
Compact and upright in habit, reaching up to 6 x 6 feet, with large foliage that resembles a Rhododendron. Some records include: 10 years - 6 x 5 feet.
The thick foliage is glossy deep green. The leaves are huge for a Kalmia.
The flowers are pale pink.
Hardy zones 4 to 8.

Bullseye
Rapid growing, dense, bushy and upright in habit, reaching a maximum size of 8 x 8 feet. Some records include: 10 years - 6 x 6 feet; fastest growth rate - 2 feet.
The wavy-edged leaves are bronze-red at first, turning to glossy deep green.
The deep purple flowers deep purple variegated with a white edge and center.
The flowers are borne on clusters, up to 4 inches across.
The stems are purplish-red.
Hardy zones 4 to 8. Very tolerant of hot humid summers.



Carol
Compact, dense and broad-spreading in habit, reaching an eventual size up to 8 x 8 feet. Some records include: fastest growth rate - 15 inches; 10 years - 5 x 5 feet.
The thick, wavy-edged, broad leaves are glossy deep green.
The bright red flowerbuds open to white flowers.
Hardy zones 4 to 8, resistant to leaf spot.

* photo taken on May 14 2012 in Howard Co., MD

Carousel
Fast growing, dense and bushy, reaching a maximum size of 8 x 8 feet.
Some records include: fastest growth rate - 14 inches; 10 years - 6 x 6 feet.
The foliage is glossy deep green.
The flowers are pink or red with white banding. They are borne in clusters up to 4 inches across.
Hardy zones 4 to 8, resistant to leaf spot.

* photo taken on May 14 2012 in Howard Co., MD

Elf
Slow growing, compact, and stiff branched; it reaches a maximum size of 6 x 6 feet.
Some records include: fastest growth rate - 15 inches; 10 years - 4 x 4 feet.
Young plants are upright, later becoming spreading.
This cultivar was developed by plant hybridizer Richard Jaynes.
The leaves are matte deep green rather than glossy.
The pure white flowers, up to 0.8 inches across, are pale pink in bud.
The stems are reddish.
Hardy zones 4 to 8, it unfortunately prone to leaf spot - do not wet the foliage unless absolutely necessary.


* photos taken on May 6 2010 @ Brookside Gardens, Wheaton, MD


* photo taken on May 14 2012 in Columbia, MD

Firecracker
Compact in habit, reaching up to 4 x 4 feet in 10 years, eventually more.
This cultivar was developed by plant hybridizer Richard Jaynes.
The foliage is glossy deep green.
The flowers are deep red in bud, opening to pinkish-white during early summer.
Hardy zones 4 to 8, it is resistant to leafspot.

Freckles
Vigorous in habit, reaching a maximum size of 6 x 5 feet.
Some records include: 10 years - 3 x 4.5 feet.
The attractive foliage is glossy deep green.
White flowers with 10 bold deep purple spots arranged around the perimeter of the center. The flowers are pink in bud, they appear on the plants at a young age.
The shoots are reddish.
Hardy zones 4 to 8. Very shade tolerant and easy to grow.

Galaxy
Vigorous and upright in habit, it can reach an eventual size of 8 x 8 feet.
Some records include; 10 years - 4.5 x 3.5 feet.
The handsome foliage is glossy mid-green.
The deep red flowers are variegated with a white center and petal edges.
Hardy zones 4 to 7.

Hearts Desire
Dense and broad-spreading in habit, reaching up to 5 x 5 feet.
Some records include: 10 years - 4 x 4.5 feet.
The foliage is purplish-red at first, turning to very glossy deep green.
The abundant flowers are deep red and edged in white.
They are borne on dense, large trusses during late spring.
Hardy zones 4 to 8, resistant to leaf spot.

Hearts of Fire
Originating as a seedling of Ostebo Red, it is vigorous and upright in habit, reaching around 6 x 6 feet. Some records include: 10 years - 5 x 4.5 feet.
The foliage is glossy green.
The large flowers are red in bud, opening to deep pink with darker edges.
Hardy zones 4 to 8, resistant to leaf spot and easier to grow than many cultivars.

Kaleidoscope
Dense and upright to rounded, reaching up to 5 x 5 feet in 10 years, eventually more.
This cultivar was developed by plant hybridizer Richard Jaynes.
The foliage is glossy deep green.
The stunning flowers are very deep red and variegated with white petal edges.
They are deep red in bud.
Hardy zones 4 to 8

Keepsake
Dense and rounded in habit, reaching up to 6 x 6 feet in 10 years, eventually more.
This cultivar was developed by plant hybridizer Richard Jaynes.
The attractive, very glossy broad leaves are red-bronze at first, turning to very glossy deep blue-green with a red tinge.
The flowers are purplish-red in bud. They open to deep red with a narrow white edge.
It is similar to Kaleidoscope but the flowers are even deeper red contrasting with the white edge.
The new growth stems are bright pinkish-red.
Hardy zones 4 to 8, resistant to leaf spot.

Little Linda
Slow growing, compact, dense and rounded in habit, reaching a maximum size of 4 x 4 feet.
Some records include: fastest growth rate - 1 feet; 8 years - 2.5 x 2.5 feet; 10 years - 3 x 3 feet. It is denser than Elf in habit.
The small, ovate leaves are glossy to waxy deep green.
The red flower buds open to pinkish-white and fading to rich pink.
Hardy zones 4 to 8, resistant to leaf spot.





Minuet
Compact and dense in habit, reaching a maximum size of 6 x 5 feet.
Some records include: fastest growth rate - 1 foot; 10 years - 4 x 4 feet.
This cultivar was developed by plant hybridizer Richard Jaynes.
The glossy deep green leaves are narrow and small.
The flowers, up to 1 inch across, are pale pink to nearly white with red-brown banding. The flowers which are large for a dwarf, are pink in bud.
Hardy zones 4 to 8, resistant to leafspot.

* photo taken on May 14 2012 in Howard Co., MD
* photo taken on Nov 3 2013 in Columbia, MD


Nathan Hale
Compact, dense and rounded in habit, reaching a maximum size of 8 x 6 feet.
Some records include: 10 years - 4 x 4 feet. It is great for use in large containers on the urban patio if shaded.
The thick, large leaves are reddish at first, turning to very glossy deep green.
The flowers are red in bud, opening to pale pink.
The flowers are borne during early summer, later than other species.
The stems are purplish-red.
Hardy zones 4 to 8, it is resistant to leaf spot.

Nipmuck
Fast growing and upright in habit, it reaches up to 4.5 x 4 feet in 10 years, eventually more.
The foliage is glossy deep green.
The flowers are scarlet-red in bud, opening to soft pink or white.
Hardy zones 4 to 8

Olympic Fire
Vigorous, dense and upright in habit, it reaches up to 6 feet or more.
Some records include: growth rate - 6 inches, 10 years - 5 x 5 feet.
The thick, wavy-margined broad leaves are luxuriant glossy deep green.
The large flowers are bright red in bud. They open to bright pink during early summer.
Hardy zones 4 to 8, it is very resistant to leafspot.

* photos taken on Oct 27 2013 in Columbia, MD


Ostebo Red
Vigorous, dense, compact and sturdy in habit, it reaches a maximum size of 15 x 15 feet after many decades. Some records include: 10 years - 6 x 6 feet; fastest growth rate - 1 foot.
The twisted, wavy-edged leaves are luxuriant glossy mid-green.
The flowers are scarlet-red in bud opening to deep pink.
Tolerant of hot humid summers.
Hardy zones 4 to 8

Peppermint
Dense and rounded in habit, reaching an eventual size of 5 x 5 feet.
Some records include: 10 years - 4 3.5 feet.
The foliage is reddish-bronze at first, turning to glossy mid-green.
The flowers are white with red stripes radiating out from a red center.
The flowers are mid-pink in bud.
Hardy zones 4 to 8

* photos taken on May 14 2012 in Howard Co., MD

* photo taken on May 14 2012 in Howard Co., MD

Pink Charm
A moderate growing, open, rounded shrub, reaching up to 6 x 6 feet.
Some records include: 10 years - 3.5 x 3.5 feet.
The foliage is luxuriant deep green.
The flowers are red in bud, opening to deep pink.
This cultivar blooms at a very young age.
The stems are purplish-red.
Hardy zones 4 to 8

Pink Frost
Vigorous, upright and rounded, reaching up to 5 x 5 feet.
Some records include: 10 years - 3.5 x 3.5 feet.
The broad leaves are glossy deep green.
The flowers are pink in bud, opening to bright pink.
They are borne during late spring.
Hardy zones 4 to 8, it is resistant to leaf spot.
Cuttings are easy to root.

Pristine
Dense and compact in habit, it reaches an eventual size of 6 x 6 feet.
Some records include: fastest growth rate - 1.5 feet; 10 years - 3 x 3 feet.
The leaves are glossy deep green.
The flowers are pure white both in bud and after they open.
Hardy zones 5 to 8, originating in South Carolina, it is more heat and humidity tolerant than other varieties however attention is needed regarding moisture as it is less drought tolerant than some other species.

Raspberry Glow
Vigorous, dense, upright and rounded, it reaches up to 6 x 5 feet in 10 years, eventually more.
The attractive, twisted, wavy-edged leaves are luxuriant deep green.
The deep red flowerbuds open to deep reddish-pink flowers.
Hardy zones 4 to 8, it is resistant to leaf spot.

Red Bandit
Slow growing, dense, compact and upright in habit, it reaches up to 4 x 3 feet in 10 years, and as much as 10 feet in 25 years.
The elliptic leaves, up to 4 x 1.5 inches in size, are glossy deep green.
The showy flowers, up to 0.8 inches across, are deep pink with deep red banding.
Hardy zones 4 to 8

Sarah
Vigorous, dense and rounded in habit, it can reach up to 8 x 8 ( rarely over 5 ) feet in 10 years, eventually more.
The broad leaves are luxuriant glossy deep green.
The flowers are red in bud, opening to pinkish-red.
The flowers are borne over a long season.
The stems and leafstalks are purplish-red.
Hardy zones 4 to 8. Heat tolerant but is more prone to over fertilize and salt than many cultivars.

Silver Dollar
Dense and rounded in habit, reaching up to 3.5 x 3.5 feet in 10 years, eventually more.
The large, leathery leaves are deep green.
The large white flowers, up to 2 inches across, are pink in bud.
Hardy zones 4 to 8

Snowdrift
Compact and dense in habit, reaching up to 5 x 5 feet in 10 years, eventually to 6 x 5 feet or more.
This cultivar was developed by plant hybridizer Richard Jaynes.
The broad leaves are bright green at first, turning to glossy deep green. The foliage remains a good green color even in winter.
The flowers are pink in bud, opening to pure white during early summer.
Hardy zones 4 to 8.

Starburst
Spreading and mounding in habit, reaching up to 5 x 6 feet.
It was originally hybridized by Richard Jaynes.
The foliage is glossy deep green.
The abundant flowers are deep red banded.
Hardy zones 4 to 8

Tiddywinks
A slow growing, compact dwarf, reaching up to 3 x 3 feet in 10 years, eventually slightly more. This cultivar was developed by plant hybridizer Richard Jaynes.
The luxuriant glossy deep green leaves are about half the size of that on regular Kalmia latifolia. The leaves are usually resistant to leaf spot.
The pink flowerbuds open to bright pink flowers.
The flowers are large for such as small plant, they are also so abundant that the plant is barely visible.
The stems are reddish.
Hardy zones 4 to 8, it is shade tolerant and easy to grow.

Tinkerbell
A vigorous dense, compact dwarf, reaching up to 3 x 3.5 feet in 10 years, eventually more. It is similar to Tiddywinks but faster growing.
The small leaves are deep green.
The rich deep pink flowers persist over a long season.
Hardy zones 4 to 8, resistant to leafspot.

Willowcrest
Slow growing and compact, it reaches up to 3 x 3.5 feet in 10 years, eventually more.
The linear, willow-like leaves are mid-green. The leaves persist for 3 years.
The flowers are pink in bud, opening to pale pink.
Hardy zones 4 to 8, it is resistant to leaf spot.

Kalmia microphylla ( Western Bog Laurel )
A small evergreen shrub, reaching up to 2 feet in height, that is native to western North America from southern Alaska through British Columbia, Washington State and Oregon. This native of swamps and bogs, is a great plant for the bog or rock garden.
The oppositely-arranged, small, lance-shaped to narrow-elliptic leaves, up to 1.5 inches in length, are glossy deep green above, gray beneath.
The purplish-pink flowers are borne during spring.
Hardy zones 3 to 6 in full sun to partial shade on humus-rich, moist soil.

Kalmia polifolia ( Swamp Laurel )
A dwarf, evergreen shrub native to northeast North America from Alaska to Labrador, south to California, Michigan & New Jersey. Usually reaching around 2 feet, the largest on record is 3.5 x 3.5 feet.
The oppositely-arranged, thin, leathery leaves, up to 1.5 inches in length, are glossy, dark green above, silvery beneath.
The flowers are vivid pink-purple in large terminal clusters in early spring.
Native to bogs and swamps in the wild.
Hardy zones 2 to 7