The genus Kalanchoe has about one hundred and fifty different species of plants, generally small shrubs or evergreen perennials, rarely these are annual plants, originating mainly from Africa, where they develop in arid or semi-arid areas, having the peculiarity of producing a succulent vegetation , well suited to survive even in conditions of prolonged drought, some species are native to Asia. Many species are widespread in the nursery, even if certainly there kalanchoe most known in Italy is Kalanchoe blossfeldiana, a small evergreen perennial plant, which gives life to small rosettes of compact leaves, with a splendid flowering. In the nursery we find many varieties and species of kalanchoes, some of which are also suitable for cultivation in the rock garden, even if they are afraid of frost, and therefore must be replaced from year to year in most of our peninsula.
Kalanchoe speciesKalanchoe blossfeldiana
Small perennial plant, mainly used as a houseplant; produces large fleshy leaves, of a glossy green color, with a serrated or wavy edge; from the apex of the thin branches in spring they rise roundish inflorescences, that carry numerous small flowers of varied color; there are many varieties of this kalanchoe, which also bear double or double flowers, which make the inflorescences opulent. When the flowers have withered it is essential to cut the inflorescence at the base, so that it is not a vehicle for infections or causes the development of mold.
Plant of easy cultivation, it tolerates drought without problems, it prefers well bright locations, even sunny for a few hours a day. In the summer he lives quietly outdoors, but prefers temperatures above 5-10 ° C, and therefore at the arrival of autumn should be kept at home, in a well-lit area of the apartment. Small plants, even after years of cultivation, tend not to exceed 15-25 cm in height.
It is a species native to Madagascar, also called elephant ears; it has large triangular leaves, with a jagged margin, covered with a thin layer of light hair, which makes them gray blue. They have a thin but robust stem, poorly branched, and the leaves tend to develop into loose rosettes; adult plants can become real shrubs, reaching the height meter without problems; small specimens are generally found in nurseries, and vegetative apexes are often trimmed to keep the shrub of small size, as in Italy they are almost always forced to grow these potted plants, as they fear the winter cold. As they grow, the large leaves tend to take on a very particular cup shape. They prefer sunny positions, or even in partial shade, as long as they receive at least a few hours of direct sunlight every day; during the winter it is advisable to store them in a cold greenhouse.
Also this kalanchoe is native to Madagascar; produces thin greyish stems, covered by a pruinose layer, little or not at all branched, which bear some large fleshy, triangular leaves of gray green color, with dark streaks and spots, almost black, especially on the margins; an adult plant in the open ground can reach a height of one meter, but potted specimens tend to stay below 50 cm in height. The particularity of this species of kalanchoe lies in its particular method of propagation: these kalanchoes do not produce flowers and seeds, but rely on a completely asexual propagation; on the margins of the leaves, tiny new plants develop continuously throughout the year, falling whenever the plant is touched or shaken; once fallen the new plants tend to root with great ease, quickly giving rise to entire colonies of plants.
Particular species of kalanchoe, always of African origin; the leaves are arranged in dense rosettes, carried by erect, fleshy stems; they have an oval shape, and are characterized by a thick white hair, which on the edges of the leaves instead becomes dark, almost brown, which gives the whole plant a decidedly unusual appearance. Among all the species of kalanchoe it is one of the most resistant to cold, and can withstand short periods of low frost. Plant of easy cultivation, it does not fear the drought and prefers quite sunny locations, and in any case very bright. Suitable specimens can reach 40-50 cm in height, which makes them very suitable for growing in pots.
Species native to southern Africa, widespread in the wild also in most of Asia; this kalanchoe produces a thick rosette of fleshy, roundish leaves, so thickly joined to form almost a head; they are almost gray in color, due to the bloom that covers them, while the edge is pink or reddish. The rosette of leaves generally does not exceed 25-30 cm in height, but the adult specimens produce thin stems, up to a meter high, which bear small fleshy flowers, of yellow color; generally every single stem has a life cycle that lasts a few years, and then dies. Very particular plant, often we see specimens that are constantly topped off the floral stem, so that they maintain a denser and more compact growth habit, which is decidedly more pleasant than that of a flowering plant. Suitable also for rock gardens, they fear intense and prolonged frost.
Prostrate or ground covering succulent plant, native to Madagascar; the whole plant is completely covered by a thin layer of bloom, which makes it light gray, so much so that in Anglo-Saxon-speaking countries it is called a powder plant. The leaves are succulent, as are the thin, well-branched stems; the flowers are pastel pink, not very bright, and bloom in apical inflorescences throughout the summer. We tend to cultivate these plains as ground cover, or in hanging baskets, so that they can fall back; over the years it is advisable to periodically trim the branches, otherwise the plants tend to be empty in the lower part, becoming less and less attractive.
There are many species of kalanchoe that we find in the nursery, but generally they all show the same cultivation needs; these are succulent plants, which can therefore allow us to avoid treating them daily, especially during the cold months; these plants love well-lit positions, even sunny ones, but it is good to expose them to sunlight only gradually, especially if we bought them during the winter.
They love loose and very well drained soils, we can use compost for succulents, or universal soil, to which we will mix a little well-washed river sand. Generally they do not like to have large amounts of space available for the roots, so it is advisable to avoid repotting them often, or to plant them in large containers. In Italian areas characterized by mild winters can find a place in the garden, in a sunny garden, or even in the rock garden, in the rest of Italy they are houseplants, or in any case to be sheltered in a cold greenhouse during the winter.
Watering is provided only when the soil is very dry, and therefore from March to September more or less once a week, intensifying watering twice a week in the middle of summer, and thinning out once every 12-15 days during cold months.
In the vegetative period kalanchoe is supplied to the fertilizer for succulent plants, every 15-20 days, dissolved in the water of the watering.
Pests and diseases
The kalanchoes manifest the typical problems of succulent plants:
If the waterings are excessive and the soil is kept moist for a long time the leaves tend to become soggy and often have dry spots; in this case it is important to let the plants dry, possibly exposing them to good lighting.
If grown in a very hot and dry place, with poor ventilation, the kalanchoes are often attacked by the cochineal, which is defeated using special products based on mineral oil and pyrethrum; on the market we also find comfortable tablets of insecticide, to be immersed in the soil, which gradually dissolve with watering, very suitable especially for plants grown in pots.
Withered inflorescences must be removed immediately, as if left on the plant they can be attacked by fungi, which can quickly be transferred to the living parts of the plant, ruining it.
Although these are succulent plants, well suited to withstand drought, if a kalanchoe is left for months without water it tends to desiccate mummifying, or the appearance looks like a living plant, but stops producing flowers or leaves, and gradually fades away , dying.
Propagate the kalanchoe
The kalanchoes can be propagated by seed, but it is not always easy to find the seeds of these plants; some of them even in nature never bloom, others take years to pass from flower to seed, others are hybrids, which are difficult to pollinate, or which give rise to seeds to plants that are not always identical to the mother plant. In any case, if we decide to sow the kalanchoes let's remember to dust the seeds with some fungicide, because the young plants recently sprouted are very subject to fungal diseases. For this reason it is much simpler and more convenient to propagate the kalanchoes by leaf cutting; the cuttings are taken in spring, or in summer, cutting the whole leaves at the base with a well sharpened knife; a bed of cuttings is prepared by mixing equal amounts of universal soil and washed river sand, and the leaves are immersed, or the larger leaves are cut into portions and simply leaned on the surface of the soil, which should be kept slightly moist. The cuttings tray should be kept in a sheltered, bright enough place, but without direct sunlight. Avoid letting the soil remain dry for a long time, and from the edge of the leaves we will see new rosettes sprout, which will give rise to individual plants; as soon as each individual plant has a height of at least 5-7 cm it will be repotted individually. In the case of kalanchoe daigremontiana the propagation is very simple, as the plants naturally produce many small specimens, which root with great ease.
Fertilize the kalanchoes
To guarantee our kalanchoes a continuous, lively and prolonged flowering it may be appropriate to fertilize our kalanchoes throughout the warm season. In addition to repotting every two years and renewing the soil and organic matter available to the plant, administer fertilizer to replenish nitrogen, phosphorus and potassium but also to supply microelements such as iron, manganese, copper, zinc, boron and molybdenum can give a remarkable hand to flowering.
The kalanchoes are to be fertilized correctly, being careful to give the right dosages. Liquid fertilizers have a faster effect but can be very risky: in case of error they do not allow adjustments to the damage.
Granular and in particular slow-release fertilizers are much safer and more permissive even if the right quantities must be respected with both.
The Latin name is Kalanchoe, it is a genus consisting of little more than a hundred plants, belonging to the f