Fat plants

Desert rose, oleander of Madagascar - Adenium obesum


GeneralitŠ°


Caduciform plant with branched stems of brown color, with a swollen base, formed both by the roots and by the stem, which has the task of storing water the Adenium obesum, also known as "desert rose" or "false baobab" is a shrubby plant native to the desert areas of East Africa. It is the only exponent of the genus Adenium and, as belonging to the Apocynaceae family, is closely related to the oleander; in fact it shares some characteristics such as resistance to drought and the extreme toxicity of many of its parts.
In the areas of origin it adapts to very different environments ranging from sandy soils to sea level, up to stony plateaus, even at high altitudes. Although it can be raised with a single trunk, in its natural state it usually develops more like a large shrub, capable of reaching even 3 meters in height.

Adenium leaves



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The leaves are oval, bright and leathery, with prominent veins on the lower base. In places of origin they are visible only during a short period of time that corresponds to the rainy season. For the rest of the year the plant is bare, to avoid an excessive dispersion of precious moisture. They are elongated and grow mainly at the apex of the branches: they have a leathery consistency and, in adults, they can reach 15 cm in length and 6-8 in width. The upper page is dark green, with central grain in evidence, extremely glossy (to reflect the sun's rays); the lower one, on the other hand, is much lighter and more velvety to counteract transpiration.

Adenium flowers



Pink, white or crimson, with darker outer margins, the flowers appear on the new branches and reach a diameter of 13 cm. The flowers are followed by bilobed green fruits.
Flowering is another point in favor of this shrub. In the summer season (but in the apartment even throughout the course of the year) of the large star-shaped corollas (up to 5 cm in diameter), in bright colors, arise directly from the bare wood. They are usually red with a white heart, but other colors are not lacking in cultivation (pure white, bright pink, soft pink). If properly pollinated, they develop pod-shaped fruits that contain seeds, feathery.

Cultivation of the Adenium



Bright and sunny, the adenium in the apartment must be exposed in full sun. Adenium obesum can be grown only as a pot plant because, although in some Italian regions the climate is very mild, in the winter months it would not be suitable.
Exposure and temperatures
It is a shrub that originates from arid or desert areas and does not know cold in nature. For your well-being, avoid exposing it to temperatures below 10 ° C. In general, from September to May must live at home or in a heated greenhouse, exposed to bright light for most of the day. When the warm weather arrives we can move it outside, even in full sun, but proceeding gradually to avoid burns. We always choose a location sheltered from the winds and, possibly, with a good level of environmental humidity, especially if we want to enjoy a beautiful flowering.

Adenium soil



The choice of suitable terrain is very important to avoid the onset of dangerous rot, one of the most frequent causes of decay. The specimens on the market are usually in a compound too peaty and therefore not at all suitable. The advice is to immediately change the vase avoiding to disturb the roots, especially from spring to autumn. We choose a fairly small container (we will avoid water stagnation and favor flowering) by creating a perfect drainage on the bottom with fine pozzolana. We then fill it with a very light bonsai compost or mixing citrus soil with sand in equal measure.

Irrigation



It is perhaps the most important aspect to keep in mind for having excellent results. The greatest damage is in fact due to over-abundant irrigation with water stagnation at the level of the roots. To have instead a luxuriant plant and with an almost continuous flowering (possible if kept indoors or in a warm greenhouse during the winter) we distribute water frequently, but very slightly. The substrate must always be fresh, but never wet. For the specimens that enter in vegetative rest it is necessary, in the winter period, to suspend completely: we will resume when the first buds will be spontaneously produced.

Adenium fertilization


Fertilization is crucial for achieving vigorous growth and sustaining flowering, which must be as durable as possible. However, it does not tolerate too concentrated products and above all with high doses of nitrogen. Good results are usually obtained with products for succulents, distributing them every two weeks. To stimulate the production of corollas, at the end of winter, we can possibly add small doses of a simple potassium-based product or very little ash.

Adenium multiplication



The most recommended propagation method is certainly the sowing, to be carried out in the spring. Germination takes place quite easily as long as it provides the right amount of heat and humidity (in places of origin it coincides with the rainy season). Some propagators also obtain specimens by grafting, on oleander; it succeeds easily and guarantees the availability of many subjects that however will not have the typical "bottle" shape and will not even be able to develop the impressive root system, so appreciated in bonsai.

Desert Rose, Madagascar oleander - Adenium obesum: Pests and diseases



The adenium has two great enemies: root rot and cochineal. The first can be prevented with a proper substrate and with very light and frequent irrigations.
To avoid serious damage from cochineal, it is instead important to frequently monitor the base of the branches and the leaves: as soon as we notice the presence, let's eliminate them with alcohol and a cotton bud. In case of strong attacks we can resort to systemic insecticides to be administered by irrigation (excellent those for the butterfly of geranium), possibly assisted by white oil.