A Kalmia in the garden
About a dozen shrubs belong to the genus Kalmia, originating in North and Central America; the most cultivated species in the garden is K. angustifolia, an evergreen shrub, with small oval or lanceolate leaves, dark green or bright green. Starting from late spring to the apex of the branches the kalmie produce large umbrella-shaped inflorescences, consisting of numerous pink or white flowers, with a rounded and flattened shape. The flowering lasts a few weeks and is very showy. There are varieties with particularly large flowers, or of unusual color, even variegated or layers.
The genre kalmia it belongs to the family of the ericaceous, like most other ericaceous, also this variety needs to be cultivated in specific soil for acidophilic plants; if we live in an area with very rich soil in limestone, or characterized by very hard water, it will be necessary to put the shrub in a pot in order to periodically check the acidity of the soil, and if it were necessary to replace it completely. The cultivation in pots does not compromise the development of the plant, also because it is a slow-growing shrub, which can therefore remain in a container whose size is not excessive even for some years. In any case we recommend a bell-shaped vase with a diameter of at least 35-40 cm, this to avoid that the earthen bread around the roots is excessively reduced, and therefore the plant is subject to drought or suffers during the cold months.
A good soil for acidophilic plants is prepared by mixing at least 3 parts of peat with a part of universal soil, a part of manure and a part of pumice stone; in this way we will have a soil with low ph, rich and well drained, so as not to keep the soil excessively soaked with water.
The Kalmia does not fear the cold, and can withstand frosts even in tense; occasionally it can happen that during particularly cold and long winters some branches get ruined: at the end of winter we will remove the blackened or dried parts due to the cold, to favor the development of new healthy branches.
These plants should be planted in a partially shady, but bright place, where they can enjoy at least a few hours of sun a day, possibly during the coolest hours of the day.
The watering of this kind of plant will be quite regular, from March to October, avoiding however to saturate the soil with water, and trying to intervene only when the substratum is well dry. These plants can easily withstand short periods of drought.
Check that water does not build up and compromise the health of the plant.
This type of plant can be multiplied through the technique of semi-woody cuttings. To be able to root the new plants it is good to prepare a mixture of peat and sand, where the new plants will have to be rooted before being permanently planted.
Diseases and adversities
This variety can be affected by the attack of pests and insects that can be effectively combated with the use of specific pesticides, to be used mainly before flowering. If there is an excess of humidity, fungal diseases can also appear which can cause a rapid deterioration of the plant.