Date: Fri 27-Jun-1997

Publication: Bee

Author: CAROLK

Quick Words:

Bleach-Gardener-laurel

Full Text:

Suburban Gardener: The Most Regal Shrub Of All

By Anthony C. Bleach

Mountain Laurel, Kalmia latifolia , has been transformed in the last twenty

years by Dr Richard Jaynes of Broken Arrow Nursery in Hamden. He has worked

with three distinct groups, based on the type, species and its two forms.

The common species K. latifolia and its cultivars have pink buds and flowers

with faint spots near the anthers. Variations include white-flowered cultivars

and redbud cultivars with intensely colored unopened flowers which contrast

with the open blooms.

Cultivars in this group include "Alpine Pink," "Brilliant," "Clementine

Churchill," "Heart of Fire," "Nipmuck," "Olympic Fire," "Ostbo Red," "Pink

Charm," "Pink Star," "Pink Surprise," "Richard Jaynes," "Sarah," "Shooting

Star," "Silver Dollar" and "Snowdrift."

Kalmia latifolia f. fuscata is the banded mountain laurel. It has flowers

which are characteristically marked with a deep maroon or cinnamon, usually

continuous, band on the inside of the corolla. This pattern has been

incorporated in "Carousel," Freckles," "Olympic Wedding" and "Pinwheel."

Kalmia latifolia f. myrtifolia (Miniature Mountain Laurel) is usually

characterized by its small leaves and more compact growth. Wild plants can

show the flower marking of the typical species or forma fuscata . Cultivars

within this group are "Elf" and "Minute."

Kalmia is named after the Finnish botanist Peter Kalm, a student of Linnaeus,

who was sent out to the New World in 1748 by the Swedish Academy of Science to

obtain seeds of plants that would thrive in the Swedish climate and soil.

Kalm was the first man to describe the Niagara Falls in English from his own

observations. His detailed studies of the mountain laurel were described in

his journal. Upon his return to Europe, he gave his collection of 325 plants

of many genera to Linnaeus, who proposed the name Kalmia .

Mountain laurels were common as ornamental shrubs in Colonial gardens when

Kalm arrived in the New World. John Bartram (1699-1777), founder of the first

American botanic garden, in Philadelphia, had sent living plants of Kalmia to

Peter Collinson, a London draper. Collinson planted the seeds and plants he

obtained from his many American business correspondents in his garden at Mill

Hill, now part of Mill Hill School, London.

The ideal planting site provides shelter from strong winds, and the harsh

midday sun in summer. A position in front of a screen of shrubs is ideal.

Kalmias do not like shade but severe late frost, when growth has started in

spring, and prolonged cold periods in winter, can cause damage in exposed

positions. Often, a position near a building is preferable though south- and

west-facing sites are best avoided when the summer daytime temperature may be

too high.

Although K. polifolia will tolerate wet, peaty soil, K. latifolia (and K.

angustifolia ) requires well drained soil that is acid or neutral.

Poorly-drained alkaline soils are not suitable. Heavy soils should be improved

by adding grit, and moss peat. Composted bark or garden compost should be

applied in generous amounts as a soil conditioner and mulch.

Established kalmias will tolerate some drought but new plantings must be well

watered. Kalmias do not require much extra feeding but if growth is weak or

pale, applications of a liquid fertilizer suitable for acid-loving plants will

benefit the plant. Their neat, bushy habits makes kalmias ideal for pots, when

they can be protected from extremes of weather, and here feeding is vital.

Dead-heading after flowering will keep the plants neat, prevent seed from

being produced and help flowerbuds form for the next year.

Pests & Diseases

Kalmias suffer from few pests and diseases, though vine weevil adults may eat

the leaves in a similar way to those of rhododendrons. The two most common

diseases are leaf spot (Mycosphacrella colorata) and leafblight (Diapothe

kalmiae) .

Clear away fallen leaves and spray new growth with bupirimate with triforine

(Nimrod-T) to control. Brown leaf tips and edges of the leaves are the result

of planting kalmias in exposed or cold positions.

Mountain laurels are now just past their best, but our horticulture club from

the college went to Broken Arrow Nursery recently to see the unique

collection.

This column was based on a report on the British National Collection of

Kalmias, in Surrey, by Alan Pullen.

(Anthony Bleach coordinates and teaches the horticulture degree program at

Naugatuck Valley Community-Technical College in Waterbury.)