The wondrous desert rose delights us on the one hand with an extremely rich abundance of flowers and on the other hand appears quite exotic with its bizarre succulent trunk. A great plant for anyone who likes a bit of variety and excitement in their living room. However, this should not apply to the development of the plant. Therefore, you will learn below how to properly care for the Adenium obesum.
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Small profile of the desert roses
The desert roses or Adenium form a separate genus in the dogbane family. The (almost) evergreen plants are so-called stem succulents, which develop thickened stems (called caudex) to improve water storage. Otherwise they grow as shrubs, with growth heights of a few meters and sometimes mighty trunk diameters in the caudex area. They grow very slowly, but can become very old, up to several hundred years.
The Adenium had to develop these water reservoirs because their homeland is in Arabia, West Africa and Central Africa, so they had to adapt to a habitat with very high temperatures, intense sunlight and the associated lack of water.
The water reservoirs of the desert rose, the caudex and the underlying transition area to the roots, are both usually very noticeably thickened, giving the whole plant an exceptionally exotic and decorative effect. However, the main part of the desert rose’s attractiveness is due to its beautiful flowers, which it forms on terminal inflorescences. So they cover the whole plant like a bell with large white to pink-red flowers, similar to the oleander.
This similarity is no coincidence: the Adenium belonged to the same tribe (Nerieae) as the oleander. It is therefore a sister genus of the oleander. You can see that quite clearly when you compare the leaves and flowers. Because of the close relationship, an oleander is also quite often used as a base to graft on an Adenium or Adenium hybrid.
Adenium obesum is the best known desert rose. The genus also includes other desert roses, almost all of which can be cultivated.
The varieties of desert roses
How many desert roses there are, or how these species relate to the desert rose genus, has long been a matter of debate among botanists. In the past they have found and described four or five or even 15 species. According to the current state of science, there are currently five species in the genus. Interesting for you in that you can buy all five species as plants or at least as seeds:
- Adenium obesum is commonly sold
- Synonyms: A. coetaneum, A. honghel, A. socotranum and A. somalense
- is sold in various well-known cultivated forms
- e.g. B. the “Fritz Dederer” with thick, corky rind
- “Mombasa”, a richly branching dwarf form
- ‘Singapore’ and ‘Red Everbloomer’ with dark pink flowers
- “Tom Grumbleys” with white flower
- Adenium arabic is quite popular
- is often cultivated as a bonsai, but also as a “normal” plant
- large and leathery leaves with a hairy underside and a more compact caudex than Adenium obesum
- Adenium boehmianum comes from Africa
- makes dense inflorescences of white to pink trumpet-shaped flowers with crimson centers
- Adenium multiflorum grows as a shrub or mini tree
- grows 0.5 to 3 meters high
- has no leaves or flowers most of the year.
- glossy green leaves up to 10 cm long and 5 to 7 cm large flowers of various colors and sweet fragrance
- Adenium oleifolium, the olive-leaved desert rose
- grows in shrubs 30 to 45 centimeters high, deciduous
- produce umbrella panicles of pink flowers with yellow accents
- occurs naturally in South Africa, southern Namibia, Swaziland and Lesotho
- prefers dry soil and does not tolerate temperatures below 1 degree plus
- Adenium swazicum from Swaziland
- grows 45-60 cm high
- likes partial shade and shade
- blooms pink to magenta in mid-spring
- some well-known hybrids such as ‘Asha’, ‘Endless Sunset’, ‘Perpetual Pink’ and ‘Volcanic Sunset’ were created by crossing with Adenium swazicum
According to another view, the genus “Desert Rose” contains only one species, namely the Adenium obesum. All other desert roses described here are considered subspecies of it. For the botanists, this means that the names listed above are simply doubled. So the subspecies Adenium obesum subsp. obesum, Adenium obesum subsp. boehmianum and so on. You might not care about that. However, precise knowledge makes a difference for lovers and collectors of desert roses in that you no longer lose track of labels with four Latin names. If “obosum” does not appear twice on plant labels with four Latin names, you may e.g. B. actually assume that you have a very rare plant in front of you.
However, you can only assume this if you buy from a specialist dealer who you know has a point of honor in naming a specific plant species. On the other hand, if you’re buying from a source that stocks whatever is selling across international trade, you can’t be at all sure of what plant you’re getting. Neither the naming of pure species or subspecies nor the naming of cultured hybrids is handled in any way in a uniform manner. Depending on the source, you can be lucky to get an Adenium at all.
A desert rose is not a “real desert rose”
To prevent another obvious confusion: the desert rose discussed here has nothing to do with the famous true desert rose, the rose of Jericho. The relationship of these two plants already ends very high in the botanical systematics. The Rose of Jericho belongs to the crucifer family. While the desert rose belongs to the gentian family.
But they both have one thing in common: If you buy a “desert rose”, whether it’s a beautifully flowering Adenium or an Anastatica rolling around as a dry ball, it can cost a lot of money, while both plants can be bought in their hometowns for a few “pennies”. have are.
The ideal location for the desert rose
If you have now managed to get your hands on a (usually tiny) desert rose in a tangle of names by paying a not inconsiderable sum in euros, you should do everything you can to make it really feel at home with you. To do this, it first needs the right location: the desert rose is used to being exposed to a merciless, blazing sun in its homeland. So you should give her all the sun you can. That means an outdoor location in summer, even directly behind the window the light intensity decreases again enormously.
As soon as (from around mid-May) and as long as (around mid-October) there are average outside temperatures of at least 15 degrees, the desert rose can go outside in the sun, in a location in full sun. When it gets really boiling hot in the middle of summer, the desert rose doesn’t mind at all. She’ll probably finally feel a little bit at home. If the desert rose does not get enough sun at its summer location, it could happen that it does not manage to develop its flowers.
maintenance
As a succulent, the Adenium obesum can go without water for a surprisingly long time if it has had a chance to replenish its stores first. By the way, she always has this opportunity with us. We generally tend to pour a little too much rather than too little, even in retail. If it weren’t, you would easily tell by the fact that the trunk would be thin and limp.
In terms of watering, this means that you have to make sure that the desert rose gets water in the heat of the summer, sometimes even plenty of water. But only if the bucket has a water drain – and if you have checked that this water drain is working. Because if you misjudge the amount of water and accidentally expose the Adenium to a longer footbath, that could have been the end of your young friendship…
As I said, overwatering is one of the favorite hobbies of Germans. In the transition period from rest to vegetation and vice versa, if in doubt, it is better to water too little than too much.
The soil for the desert rose should be very permeable so that all excess water can drain off. It’s good e.g. B. a mixture of 30% garden soil and 70% loosening material. You can use sand, pumice, perlite, coconut material or small pieces of wood to loosen it up, with coarse sand being one of the favorites in terms of value for money and appearance.
During the growth phase, the desert rose then needs some fertilizer about once a month, which should have a balanced NPK ratio (NPK 8-8-8 or 7-7-7 or 6-6-6, for example).
wintering
While an Adenium in its homeland simply sheds its leaves and goes into a dry dormant state with every dry spell, in our home it has been busy growing all summer long. However, this was under conditions that can at best be described as “moderate”. The Central European summer is too little light for the desert rose, and the winter quarters will definitely be too dark for it.
This takes strength, so you should force your desert rose into a dry dormant period over the winter to allow it to recover. You can do this by starting to reduce the watering as early as late summer. In autumn you should then water a little less and when the Adenium has moved to winter quarters, stop watering completely. The remaining moisture must be able to dry off well so that the desert rose falls into a dry rest.
It is fundamentally important for the survival of your desert rose that you set and keep the substrate almost dry in autumn and almost dry in winter. Only in dry dormancy can it survive the low-light period without damage. Once this dryness has been established, the desert rose can even withstand a moderately bright location during the rest period. She’s out of leaves anyway and has stopped her metabolism as much as possible. But she would like it to be reasonably warm. At least 15 degrees, and under 10 degrees, it should never be in their winter quarters.
The difference to wintering in a 18-degree cool bedroom is no longer that big. But the desert rose is bitchy in this respect: With exactly these few extra degrees, it usually no longer falls into a dry dorm and has difficulties with flowering in the next season. The same applies to the Adenium, which is cultivated without a rest period with normal supply and at room temperatures. They usually don’t have enough strength to develop flowers in the next season.
Preparation for the summer season
When winter is finally over, you can immediately move a leafless desert rose outside to full sun, temperatures permitting.
If it has leaves when you clear it out, the plant should not be placed directly in the blazing sun, even in the moderately temperate spring. Rather, the leaves should first be accustomed to the sun for a few days. Leaves can also get sunburned, but they usually don’t heal anymore. This phase of getting used to a place that is as warm and bright as possible also helps the desert rose with the formation of new leaves and the preparation of the flowers.
Incidentally, watering is not carried out immediately with the same increasing intensity, not even when the desert rose has just got a few nice little new leaves. You should only start watering when the temperatures have already clearly reached summer values and when the plant shows you all around that it intends to “burst out of every corner” in the near future. Only then will it be poured. The beginnings of the flowers should also appear in the near future. Then, under certain circumstances, a little more water is required and there is also the first careful application of fertilizer.
