The Gasterias (sometimes known by such common names as “Bow Tie Plants” or “Cow’s Tongues”) have been popular succulents for many decades for their ease of culture, their tolerance to relatively low light levels, their interestingly patterned foliage, and their many cultivars with beautifully variegated foliage. Many species, and many dozens of named varieties are readily available in the trade at reasonable prices, and most of these plants are reliably pest and disease resistant. Most plants are compact growers which can be maintained in smaller pots and planters for many years. While there are a couple of species (G. croucherii, and G. acinacifolia for example) which are much larger plants, and may eventually grow to several feet high or more, these are the exceptions to the rule: most species may top out at about 6 to 8 inches, and a few seldom grow much taller than a few inches. Practically every species has unusual arrangement of leaves in which the leaves are curiously stacked one on top of another in two ranks, (the proper term is that the leaves are “distichous”) giving rise to one of the common names for this genus, the “Bow Tie” plants – seen from above, the plants have a bow tie appearance. In some species, as the plants mature, they produce their leaves in a rosette, but many species continue to produce this “bow tie” arrangement throughout their lifetime.
These plants are closely related to Aloes and Haworthias, and many hybrids have been made between these groups (sometimes listed as “Gasteraloes” and “Gastwothias” in the trade). The trait which distinguishes the Gasterias is their unusual flowers, which are tubular with a noticeably enlarged bases and midsections. These flowers were regarded as stomach shaped, and
the genus was named Gasteria (“Gaster” meaning stomach) accordingly.
It is hard to find a consistent number of accepted species for this genus, as the species are highly variable, and all of the species can readily hybridize in habitat, making absolute IDs difficult. I have seen the numbers of accepted species ranging from about 2 dozen to about 50 species, depending upon the author. In cultivation, there are probably hundreds of named hybrids and cultivars. All of the species are native to Southern Africa, including Namibia, and most species typically grow in somewhat shaded conditions – usually in the shade of larger plants, or perhaps on the shaded side of hills and canyons.
Gasteria rawlinsonii is perhaps the most distinctive species of the genus, and it is unlikely to be confused with any others. The species is adapted to growth on cliffs, and as a result, the stems typically hang over the edges; to our eyes, hanging “upside down”. Also, the stems can grow very long – one source indicates that the stems can grow to lengths of 6 feet or possibly even
longer, but given the slow rate of growth of the Gasterias, such plants would probably take decades to achieve these sizes in cultivation. Wikipedia offers the following information on its habitat and distribution:
This species is restricted to the Baviaanskloof mountains, in the Willowmore District of the Eastern Cape, South Africa. Here it tends to grow hanging on cliff faces in shady ravines, growing in well-drained sandstone soils, usually on the shady south-facing cliffs.
It is my understanding this species has such a restricted range that it is fairly rare in habitat, and that its cliff hanging habit makes it a challenge to collect plants and seed, so over the years it has been pretty hard to find plants for sale. On top of this, it is slow growing and divisions are only offered sporadically. I suspect that seed raised plants may take several years to reach a marketable size, so it may remain a hard-to-find item for some time. Even so, just because it may be hard to find, doesn’t mean that it is hard to grow, quite the contrary, like the overwhelming majority of Gasterias, this is a forgiving plant, tolerating a variety of growing conditions and soil mixes. While in habitat, it favors shaded habitats, and it is better adapted to somewhat lower light levels than most other succulents, in cultivation it is still best to give it bright but indirect light.
While most growers pot this plant on top of the pot and allow the stems to cascade over the sides, I have taken the more extreme measure; I have potted my plant in the drainage hole of a hanging basket and to let it grow naturally “upside down”. Its cliff dwelling habit also suggests that good sharp drainage is particularly important to this plant, so make sure that it is given a good gritty
mix, but also make sure that the soil contains essential nutrients – this plant cannot thrive in just grit and sand. I do a lot of composting in the garden, and have found that a succulent mix that includes a good amount of well-rotted leaf compost is particularly favored by many of my plants.
But lacking this, it may be a good idea to provide regular (monthly) application of a low nitrogen liquid fertilizer (dilute the fertilizer to about ¼ of the recommended application rate). I only apply fertilizer during the growing season (from the warmer months of spring through the early weeks of fall). While I have not paid much attention to the pH of my potting mix, the fact that plants in habitat typically grow on sandstone cliffs would suggest that this species is adapted to somewhat more acidic soils, so it may be beneficial to incorporate some peat moss into the growing medium as a soil acidifier (or water the plant with tea water from time to time). The occasional application of a commercial soil acidifier may also be beneficial – but always use such acidifiers in moderation, – as with fertilizers, it is usually best to dilute these to about ¼ of
the recommended application rate. When in doubt, use less. In its natural habitat, Gasteria rawlinsonii may receive anywhere from about 10 to 15 inches
of rain in an average year, and while this is considerably drier than Columbus, this is still moister than most desert habitats – do not water with a teaspoon or an eye dropper! When watering, Water it well, and during the warmer months, water it regularly, but make sure that the soil does not remain saturated for extended periods (if it does, it needs a more gritty potting medium). Let the potting medium become dry before watering again. Plants in habitat may receive rain in any season, but the majority of the rain falls during the summer months, as a result, this plant will produce the majority of its growth in spring and summer. But it can grow and flower through much of the year, suggesting that it is an opportunistic grower – growing and flowering whenever conditions permit. I choose to keep my plant cooler and drier through much of fall, winter and into early spring, and I do not fertilize my plant at all during this time. Because
daylight is in short supply at these times, I want to prevent any growth at these times to prevent weak and etiolated growth. When temperatures permit (when temperatures reliably rise above about 45 to 50 degrees) I move my plant outdoors into open shade to dapple shade – my front porch provides a good habitat for this. Later in the season, as it adapts to brighter conditions, I
may move it to slightly sunnier conditions – but I will never move it into full sun, as I fear that this may possibly scorch its foliage – any such damage will permanently mar the appearance of any affected foliage.
To date, my plant has not flowered, I suspect that plants need to sufficiently mature before they will regularly flower. My experience with other Gasterias is they they can be successfully self-pollinated, at least with a bit of assistance, so I am hopeful that when my plant flowers, I will be able to produce viable seed, and will be able to supply some nice seedlings in years to come.
Gasteria rawlinsonii is perhaps the most unusual and attractive species of the Gasterias. Its unusual cascading growth habit, and its unusually long stems makes it exceptional; a well grown specimen practically commands attention. Even though it remains fairly hard to find, it is not hard to grow. Like other Gasterias it is a forgiving plant, tolerating a good amount of benign neglect. It tolerates lower light levels than most succulent plants, it is possibly more pest free than most Gasterias (its well-spaced leaves do not conceal insects like some other Gasterias can).
I highly recommend this plant; it is my favorite of the genus. If you ever find one for sale, by all means, give it a try. – author Bruce Brethauer
Gasteria rawlinsonii varieties – Kirstenbosch 6 – Gasteria – Wikipedia
Gasteria rawlinsonii – staircase 5 – Gasteria rawlinsonii – Wikipedia
Gasteria rawlinsonii-IMG 0692 – Gasteria rawlinsonii – Wikipedia