by Bruce Brethauer
My first association with the Huernias dates back to the early 1970s – and this species, or another very close look-alike, was the first member of this genus which I had grown. Over the ensuing years I have grown many other Huernia plants - usually growing them for a time, and then passing them on to another grower. Invariably, I keep returning to the Huernias; they have a lot of traits which I find appealing. They are relatively small plants with low, mounding, and sprawling habits, many species are easy to grow, and when provided with adequate growing conditions, will produce significant growth each year - smaller plants can easily double or triple in size in a single growing season, and where they are happy, are reliable bloomers as well. Most species typically produce their flowers in Summer and into Fall, but some plants may produce flowers intermittently over a extended period - sometimes beginning in spring, and extending into winter. Flowers are typically smallish, shallowly cup-shaped, and are (usually) dark maroon, but there are some very interesting variations in different species, with heavily papilliate flowers, interesting markings, and curious lifesaver-shaped annulus. After many years of waiting, the "Big Box" stores are finally starting to add some of the more interesting species to their succulent plant selections, including Huerina zebrina, which has one of the most bizarre and striking flowers of the genus. Flowers are typically produced at the base of the plant, usually on new growth. The Huernias are members of the greater milkweed family, but unlike their other succulent relatives, the flowers of the Huernias do not typically produce the foul scent of rotting flesh. Depending upon the authority cited, there are between 30 and 60 species of Hueneria recognized – all are native to eastern and southern Africa.
Plants of Huernia aspera produce 5 to 7 angled stems, to about 1/2 inch in diameter on my plants, with succulent, fleshy stipular prickles along its ribs. The stems are initially upright, becoming more scrambling as the stems grow longer. At present, the tallest stems on my plant are about 5 inches tall, with a few longer stems growing prostrate, but I have seen plants with stems to just over 1 foot in length, and at least one online source suggests that the stems of some exceptional plants can exceed 3 feet in length. This species quickly ramifies from its base to produce a many-stemmed tufted/sprawling plant. In time, plants will spread in this manner to about a foot or more across (possibly to several feet in diameter). The ultimate spread of this plant can be limited by a the size of the pot, and (if necessary) by occasional pruning, so that a plant in cultivation can be maintained at smaller sizes as needed. Typically the stems are of an apple green coloration, but when grown outdoors in full sun, may become somewhat bleached, producing more yellowish hues.
The flowers of this species are typically of a dark maroon coloration; on casual observation, the flower appears to have uniformly colored petals, with a darker sunken "pit" in its center; but upon closer examination the petals may reveal subtle color variations, with a patchwork of tiny yellow to beige splotches towards the edges and tips of the petals. Close examination of the center portion of the flowers will reveal intricate patterning in nearly black tones at the flower's inner base, as well as its elaborate outer corona. The flowers measure approximately 1 to 1.5 inches in diameter in most plants, and are invariably produced at the very base of the stems, and are typically produced on new growth. The low position of the flowers on the plant would suggest that the primary pollinators of these flowers are ground dwelling insects - possibly beetles or ants. Following pollination, the plant typically produces two horn-shaped fruits ("pods"). When the "pods" have ripened and dried, they split lengthwise to release seeds on a silken "parachute", - typical of all members of the greater milkweed family. In cultivation, plants are usually propagated from stem cuttings or small offsets. When growing from cuttings (these are best taken in spring or early summer when the plants are in their growth cycle), set aside the cuttings for a week or two to allow the cut ends to heal and callus, then press these cuttings into soil which is maintained kept evenly moist to barely moist, and the stems should set roots in two or three weeks. Plants may also be grown from seed, however, it has been my experience that Huernia seedlings are highly susceptible to damping off, and will take a bit linger to become established.
Huernia aspera is one of the most widely available of the Huernia species, this species, and a few of its close look-alike cousins are frequently carried in the succulent plant displays at local and "Big Box" nurseries, and is readily available from a majority of mail-order nurseries specializing in succulents. This an easy plant to grow, presenting few challenges. It responds well to my general guidelines for growing succulents, with a few considerations. This species grows particularly well during the heat of summer, and should be grown outdoors at this time, although it may benefit from a bit of dapple shade through the hottest portions of the day (heat and drought stressed plants may tend to take on yellowish hues). This species is a bit more cold tolerant than other huernias, but even so, it should not be subjected to extended periods of chill (some online sources suggest that this species will tolerate a few degrees of frost - with one or two sources suggesting that it will survive temperatures down to 25 or even 20 degrees Fahrenheit, but I take such claims with a grain of salt; it may perhaps survive very brief exposure to frost, but I would not expect it to survive a hard freeze, or even a extended exposure to temperatures in the 40's. I am of the opinion that this species should be maintained at temperatures warmer than 50 degrees through its winter dormancy for best health. Cold stressed plants are particularly susceptible to stem rot, – keep an eye out for soft dark spots on the stem, and cut away any diseased tissues before the pathogen has an opportunity to spread. This species can also be attractive to mealy bugs, so be on the lookout for this pest - especially when re-potting the plant, as this plant can harbor root mealy bugs as well as the stem dwelling species.
Huernia aspera is one of the easiest of the Huernias to grow and flower; where conditions are to its liking, it will put on significant growth each year; it is also reliable bloomer. This a suitable plant for households with pets or very young children; the fleshy prickles are soft, and do not cause injury - and the plant is does not appear to be toxic: most Huernia species are considered edible by the native peoples throughout the range of this genus. Although the flowers are smallish, and may not look exceptional at first glance, on close examination, (keep a powerful magnifying glass handy) they reveal a complexity and curious beauty. This species (or one of its close cousins) can frequently be found in the mixed succulent selections at the "Big Box" stores and other nurseries. It is easy to propagate plants from cuttings, so starts can frequently be found at shows and sales of cactus and succulent societies. The ease of culture, and rapid growth rate of this plants makes it especially good as a starter plant for novice, and young growers, but even experienced growers will find this plant to be an attractive and curious plant. If you ever encounter this plant at a nursery, or a plant show, by all means, give it a try.