First of all, for my readers who celebrated Christmas hope you had joy and fun with your loved ones. Secondly I have an update to you. In today’s blog post I would like to talk about 3 different type of plants. These plants are dioscorea elephantipes, edithcolea grandis and euphorbia obesa.
What is common in all 3 is that I have recently bought seeds online and I have just made a potting video, which you can watch here: Potting of the seeds – you might ask, but it is winter! You shouldn’t sow seeds now! You are right, but this year, the winter is pretty mild, where I live, not to mention there is always a good amount of sun. So I am quite optimistic and hoping it works out well!
Without further delay let’s start talking about these plants. First I would like to talk about dioscorea elephantipes.
What everyone notices first is the strange shape and look. This is also why I have decided to acquire some seeds. It is a deciduous climber. It takes the name “elephant’s foot” from the appearance of its large, partially buried, tuberous stem, which grows very slowly but often reaches a considerable size, often more than 3 m (10 ft) in circumference with a height of nearly 1 m (3 ft 3 in) above ground. It is rich in starch, whence the name Hottentot bread, and is covered on the outside with thick, hard, corky plates. It requires significant processing before being eaten to remove toxic compounds.
Primarily a winter grower, it develops slender, leafy, climbing shoots with dark-spotted, greenish-yellow flowers in winter (May or June in habitat). The flowers are dioecious, with male or female flowers occurring on separate plants.
Its natural habitat is the arid inland regions of the Cape, stretching from the centre of the Northern Cape (where it occurs around Springbok), south to the Clanwilliam & Cederberg area, and eastwards through the districts of Graaff Reinet, Uniondale and Willowmore, as far as Grahamstown.
It was recently rediscovered in a section of the Northern Cape Province by an expedition collecting seeds for the Millennium Seed Bank Project.
In this area, it is most common on rocky north & east-facing slopes, in quartz or shale based soils.
This species is not difficult to cultivate, however it requires extremely coarse, well-drained soil, and sparse watering. Importantly, it is deciduous and loses its leaves in the summer. At this time it goes through a dry dormancy period.
This species indicates when it is requiring water, by the presence of green growth. From when a new growth appears from the caudex, it can receive regular watering, up until the growth withers and dies back. This is when the plant goes into its summer dormancy. Then watering should become more rare – until the next new growth appears.
The cycle can be extremely unpredictable or erratic, but in most cases this results in a watering regime of wetter winter and spring, and a dry summer dormancy period.
Sun & shade
In nature, the caudex is usually in shade beneath thicket vegetation, and only the leafy tendrils reach up to the sunlight. Therefore the caudex is sensitive to prolonged exposure to heat and full sunlight, and a dappled-sun or semi-shaded position is preferable. The green vine tendrils however, thrive if they are able to reach partial or full sunlight.
This plant grows naturally in brush on rocky slopes, so it requires extremely well-drained soil, with a large (at least 50%) mineral component.
Second is the edithcolea grandis.
Edithcolea is a monotypic genus with a single species Edithcolea grandis (Persian carpet flower). Once classified in the family Asclepiadaceae, it is now in the subfamily Asclepiadoideae of the dogbane family Apocynaceae. It is native to Africa and to the Arabian Peninsula.
The genus is named after Miss Edith Cole (1859-1940). She collected the type material for this plant together with Mrs. Lort Philips in 1895, during a botanical expedition (1894-1895) led by Mr. Ethelbert Edward Lort Phillips (1857-1944) from Berbera to the Golis mountains in northern Somalia.
Edithcolea grandis is a succulent plant with leafless richly branched perennial and decumbent stems with a diameter of 2 to 4 cm and up to 30 cm in length (ref prota, ref Field 80). The glabrous stems are 4 or 5 angled and armed with regularly placed hard and acute spinelike teeth or tubercules. The base color of the plant varies from green to red with brownish spots.
The bisexual flowers are 8 to 13 cm in diameter and are formed near the apex of the branches. The flower consists of an outer corolla with 5 corolla lobes (petals), which are fused halfway to the center and a relatively small inner corolla. The outside or back side of the flower is yellow to green. The inside consist of a pale yellow base color with a purple-reddish pattern of spots at the outside that gradually become smaller near the inner corona, which has itself has concentric reddish lines. Long purple hairs are present at the border of the brim of the outer corolla lobes. The remarkable flower is at times described as the Persian carpet flower. The carrion-like smell of the flowers attracts flies and other insects for pollination.
The fruit (follicles) contain a large number of seeds. The oval shaped seeds bear a tuft of hairs (coma) so they can be dispersed with the wind. The smaller variant baylissiana (Lavros & Hardy) has more branched stems that are smaller in diameter (1 to 1.5 cm), shorter (10 cm) and are often spirally twisted.
Edithcolea grandis is distributed throughout the African Great Lakes region (Kenya, Tanzania, Uganda), the Horn of Africa (Ethiopia, Somalia) and Yemen (including the Socotra archipelago). The plant is found in dry and arid regions. Sometimes in full sun, but mostly partly shaded by rocks and shrubby vegetation.
Usage and growth
Edithcolea grandis is occasionally cultivated as an ornamental in desert gardens worldwide. It has a gained a reputation as a particularly difficult plant to keep because of its very specific growing needs with much light and relatively high (above 15 °C) winter temperatures. It’s very susceptible to rot in combination with low temperatures.
Third and last plant is the euphorbia obesa.
Euphorbia obesa is a subtropical succulent species of Euphorbia genus. It comes from South Africa, especially in the Cape Province. Sometimes referred to as a Kaffirhuisie, or a Baseball plant. In the wild, it is endangered because of over-collection and poaching, because of its slow growth, and the fact that the pod contains only 2 to 3 seeds. However, it is widely cultivated in botanical gardens.
Euphorbia obesa resembles a ball, thornless and decorative. It is commonly known as ‘baseball plant’ due to its shape. Its diameter is between 6 cm and 15 cm depending on its age. Young Euphorbia obesas are spherical, but become cylindrical with age. They contain water reservoirs for periods of drought.
The plant is dioecious, which means that a subject has only male or female flowers. The small flowers are insignificant in apex. In fact, like all Euphorbia, flowers are called cyathia.
As in all Euphorbia species, the latex is toxic.
Living in similar conditions on two different continents, Euphorbia obesa presents a form of convergence with Astrophytum asterias which is a cactus from Mexico.
This species is indigenous to a small range in the arid Karoo region of South Africa. This is a region of summer rainfall.