Orbea

Family: Apocynaceae
Habitat: Africa: South-eastern Africa and Arabian peninsula.
Cultivation: In general, a half-shaded position, an unfrequent watering and a well-draining, sandy soil will do well.
Curiosity: The name Orbea comes from the latin word “orbis”, that means circle, disk. That’s because of its star-shaped fleshy flower, which has a raised, more or less prominent disk or annulus in its central part.

KEY FEATURES

Orbea is a genus of around 58 succulent plants native to southern and estern Africa, but also present in arabian peninsula. It is more or less equally divided between the northern hemisphere (arabian centre of distribution) and the southern hemisphere (southern african centre of distribution).

Regarding the conservation status, the red data IUCN includes 15 succulent species, most of them listed, in the IUCN classification, in the “Least concern” category, which means that they aren’t threatened with extinction. Only O. elegans is listed in the “Critically endangered” category, while O. woodii and O. macloughlinii are listed as “Vulnerable”.

This genus is closely related to Stapelia. It was decribed by a botanist called Haworth for the first time in 1812, then included in Stapelia genus. In 1975 though, another botanist called Leach reintroduced Orbea as a separated genus again. That’s the reason why there’s still some confusion regarding the name os this species: until 1975, in fact, most of them were classified as Stapelia or Caralluma.

With the Stapelia group Orbeas share their fleshy, fashinating, star-shaped with five petals, colorful flowers, characterised by beautiful textures: a tigred, dark read and orange weave in O. schweinfurthii, a red and yellow leopard print pattern in O. namaquensis and in O. hardyi, a deep red with orange and black tinges in O. semitubiflora. This remarkable diversity of the flowers is the answer to the adaptation of this plant to a wide range of different fly pollinator species: each colorful plot attracts different species. Also, some species are equipped with vibratil hairs, which, presumably, act also as attractors of flies, together with the smell of this flower.

Seeds go through an airborn dispersion. They possue a tuft of white hairs, called coma, which ensure their spread through the air.

Orbea are mat-forming, small succulents, which don’t overcome a few centimeters in height. They are sought after by succulent collectors for their remarkable flower an for their small dimensions. A beautiful result could also be obtained by putting them in a hanging pot to make them fall down.

These plants don’t have leaves: the photosynthesis is therefore carried out by the succulent, bluish-grey tinged in red, stems. The former are four-angled and show these pointed teeths, which are actually tubercles. They can be erect or creeping. Their purple tinge become more intense if the plant is exposed to direct sunlight.

The succulent nature of this group enable Orbea to go into a dormant state during part of the year, during which the plant stops growing and uses the water and nutrients stored in its succulent stem. It is important for growers to know from which region the plant is native to, in particular whether they are from summer- or winter-rainfall areas, to know when to stop watering and give the plants the opportunity to go into a rest phase. Therefore, if your Orbea is native to the arabian peninsula, its dormancy period will probably be from March-May to September-October, while, on the contrary, Orbeas native to the southern hemisphere will enter dormancy in the period between September-October and March-April.

VARIETY AND TYPES

Here are a few species of Orbea. Check our online store to find some of them!

  • O. deflersiana
  • O. distincta
  • O. dummeri
  • O. halipedicola
  • O. hardyi
  • O. namaquensis
  • O. schweinfurthii
  • O. semitubiflora
  • O. semota
  • O. variegata

TIPS FOR GROWING

  • The recommended exposure is half-shaded: in their natural environment, these plants usually grow in the shade of other bigger bushes or trees. A few species, however, love direct sun. To be sure you could put them in a position in which they receive only early morning and late afternoon sun
  • Temperature hardiness depends on the species: anyway don’t keep them at temperatures below 5-8ÂșC.
  • It’s difficult to give general indication regarding irrigation: watering necessities depends in fact on the original habitat of the plant. Species native to wetter region need obviously more water. It’s also important to know, as already mentioned, if your Orbea comes from a winter or Summer rainfall areas, to know when to suspend irrigation. In general, when you notice an active growth, you should water more often. Water rather scarcely than exceedengly, cause these plants can survive to long drought periods, but don’t let the stems strink too much
  • Orbeas need a well-drained, sandy substrate. A standard soil mix with added sand (when possible), will do well;
  • Repotting necessities depend on the species. Remember anyway to use shallow, wide pots, as these plants tend to expand horizontally, and repot when you notice that they have taken all the space in your pot. These plants grow rather fast;

Propagation can be easily carried out through stem cuttings, which should be taken off before the plant enters its dormancy period. On the other hand, also seeds germinate easily.

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