Orbea variegata - Cactus Club

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Orbea variegata

Plant of the Month > Species O to P
 
 

by Bruce Brethauer         


          Orbea variegata is a popular and attractive member of the greater Milkweed Family (Asclepiadaceae) with clustering, succulent stems, which typically grow to about 4 inches in height, with pronounced, pointed tubercles in two ranks. Stems are branching, ramifying from its base, eventually spreading to form low mats to a foot or more across. New growth is a bright, apple-green, with purplish markings on, and around the tubercles, but as the stems age, they tend to fade to a paler, more grayish-green.  

            The Flowers are especially distinctive; these are large in proportion to the size of the plant (from about 2 to over 3 inches across), with 5 very broad petals, and a prominent raised central disc (annulus). This annulus, is one of the traits which distinguishes this Genus from its very close cousin - Stapelia (Many authorities continue to lump the two Genera together). The base color of the flowers is a pale greenish yellow to butter yellow with reddish purple to brownish dots and splotches. Typically, the flowers of most plants are significantly ridged - like crepe paper. The plant illustrated here, is not typical: the central disc and petals of its flowers are nearly smooth. The petals are lined with spoon to club shaped Club hairs, which flutter at the slightest breeze (and may very well move at the slight breeze created by any winged insect as it approaches the flower). The club hairs may play a role in the dispersal of the scent produced by these flowers; like its close relatives, the Stalepias, the flowers of this species also produces the scent of carrion to attract flies and carrion beetles which pollinate its flowers, but the scent is not nearly as pronounced as it is in the Stapelias. Flowers are produced very low on the stems on new growth, typically lying on the ground: in potted plants, the flowers may hang at the sides of the pots. A succession of flowers are produced over the greater portion of summer, and reputedly into fall.

            Orbea variegata is native to eastern and western Cape Province region of South Africa, and is highly variable in its traits - White and Sloane identify some 19 varieties, and since this species has the tendency to hybridize with other Orbeas and Stapelias (apparently, in both cultivation and in habitat), there is a lot of confusion on the limits of the traits to be found within this species.

       Interestingly, this species was the first of the succulent Stapeliads to have been introduced to Europe. Estimates vary, but it is believed that this plant was first introduced to European growers in the mid 1600's, and and has been grown in collections virtually ever since then. It remains a very popular species with growers - it has a number of traits which makes it especially popular: it is a reliable and forgiving plant - tolerating a variety of growing situations, and producing very good growth where conditions are to its liking. It is easy to flower, reliably producing a succession of blooms over a long period of time. The flowers are both odd and curiously attractive, and the plants can be maintained in comparatively small areas.

             This is an easy plant to grow and flower in cultivation; it responds well to my general guidelines on growing succulents, with a few considerations. Plants grown indoors should be provided with as much light as possible - more is better:  If you are habit of moving you succulents outdoors during the warmer months of summer to benefit from sun, rain and warm temperatures, you can expect some exceptional growth. Here in Ohio, it tolerates maximum exposure to daylight, but at higher elevations, or in the desert southwest, it will probably benefit from a bit of dapple shade - particularly during the hottest hours of the day. Given regular watering, and monthly applications of dilute fertilizer through the growing season, its growth rate has been exceptional, easily doubling or even trebling in size in a single growing season. It appreciates a dry and cool winter dormancy - it would probably be best to maintain its winter temperature at about 50 degrees warmer - cooler temperatures may make it susceptible to bacterial and fungal infestations - especially if it is exposed to humid conditions at this time. It is my understanding that it is probably best not to water this plant at all in the winter. When temperatures rise again in spring, resume more frequent watering, and once growth begins, provide monthly fertilization. To date, I have not seen any evidence of insect pests on my plants, but it may be wise to keep an eye out for mealy bugs and spider mites. It may also be a good idea to be on the lookout for any signs of fungal or bacterial infections - if any stems become discolored or turn mushy, trim these off and keep a close eye on this plant for any signs of additional issues.



           Propagation is easy from cuttings. Cuttings can be taken at any time of year, however, for best results, it would be best to start cuttings in spring or early summer, when the plant is actively growing. Set aside a cutting for a few days for the end to heal, and lay the cuttings on the surface of the potting medium, and press these down so that there is good contact between the stem and the soil. Roots should be established in a few weeks to a few months - stem growth and branching will soon follow. It may also be possible to grow this plant from seed, although I am uncertain if this plant will readily self (two clones may be required for seed to set).

           Given the ease of care, the rapid growth rate, interesting qualities, and the smaller stature of this plant, I am surprised that it has not proven to be a more popular. I acquired my plant from a chance appearance at one of our local nursery chains, otherwise, I have never seen it at any of the "big box" stores here, and even the specialist mail order nurseries do not regularly offer this plant. It is frequently offered at Miles to Go, and Bob Smoley's Gardenworld. Groovy Plants Ranch grows and propagates this plant, but does not offer it on their website at the present time. Its relative scarcity here is surprising - in Europe, it is one of the most commonly grown species of the succulent "Milkweeds", here it remains a bit of a novelty. If you should ever come across this plant in your travels, give it a try - in my opinion, it is one of the most attractive and interesting plant of this genus.



 
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