Sansevieria - September 2017, May 2015, April 2011, November 2009, April 2008 & 2007, September 2006
To many cactus and succulent growers, Sansevieria is something of an oddball group that gets thought of more as a houseplant than a real succulent. While it makes a great houseplant, it is an unfortunate way to look at this interesting genus of plants. I like to think of them as one of the very few groups of succulents that can tolerate, and even thrive in low light situations such as life inside a home. While most species can do well In-doors, that is by no means the required or preferred way to grow them. In our mild climate they can grow outdoors year round and make a great addition to the shadier spots of your landscape. They are among the easiest to grow and most tolerant of abuse of all succulents.
Sansevieria is a genus of approximately 70 species in the Asparagus family (Asparagaceae). Most species occur in Africa though some species have found their way to India and even Myanmar (Burma). The most notable differences between species are the length and shape of the leaves, as well as the coloration and patterning of the leaves. The common names "Snake Plant" and "Mother in law's Tongue" come from the long, stiff, pointed, and mottled leaf appearance of the most commonly grown species. However, some species produce much more interesting and unique leaf shapes. In particular, species such as S. cylindrica have leaves that are nearly circular in cross section.
In cultivation, many interesting hybrids and cultivars have been produced. Sansevieria hallii has several cultivars which carry variations on the the name "Baseball Bat". The name really is fitting as the leaves are very thick and tough. One of the most attractive species is S. kirkii. It has wavy leaves that are produced horizontally or at least low to the ground. The species has a brown to bronze cast which has been the basis for hybridization and cultivar selection. Cultivars such as "Coppertone", with its rich bronze and pinkish brown coloration, really show how beautiful the coloring of a Sansevieria can be.
Among the most popular types of Sansevieria are variegates. Most everyone has seen S. trifasciata 'Laurentii' even if you don't know it by name. It has long upright leaves with a yellow margin. It is not only one of the most popular Sansevieria, it is among the most popular of all houseplants. However, that is the tip of the iceberg. Variegates of S. pinguicula, S. robusta, S. kirkii and others can sell for $100 or more! For those looking beyond the typical yellow variegation, "Silver Streak" and "Siam Silver" are great plants with silvery-white variegation.
In recent years "minature" Sansevieria have become popular. They tend to have rounder leaves which only get a few inches long and look great in small pots. Unfortunately, most of these "minatures" are actually the juvenile forms of full sized species. Not only is the adult bigger, but it looks like a completely different plant. Sansevieria pinguicula and S. eilensis are examples of this. One of the only "minature" species I'm aware of that stays small and retains much of its juvenile look into adulthood is S. rorida.
Cultivation of most species is quite easy. They thrive in most any well drained potting mix. Outdoors they can grow in similar light conditions as Gasteria and Haworthia (i..e. bright shade, maybe some morning sun) or even shadier spots. They do well in ground, though they don't like being in an cold and wet for excessive periods. Propagation is simple. Either divide a large plant or grow new plants from leaf cuttings. Do note that leaf cuttings of variegated plants virtually always produce regular, non-variegated plants.
— Kyle Williams
Sarcocaulon - February 2015, January-February 2009, February 2008 & 2007
It is important to have a discussion about the proper name for these plants. Traditionally, Monsonia has referred to the plants in this group that are herbaceous while Sarcocaulon referred to the species with fat, woody stems (Sarcocaulon means "fat stem"). However, nearly 20 years ago botanists determined they were all members of the same genus, and the proper name for the genus is Monsonia not Sarcocaulon. More recent studies using the DNA of the plants confirms this finding is correct. While some may think it odd to have the herbaceous and woody species together, it really is no big deal. You only have to look to Pelargonium to see that a diverse array of species, from herbs, to woody shrubs, to geophytes, all happily coexist in one genus without anyone raising an eyebrow.
We focus on Monsonia, the Bushman's Candles, a genus of small succulents and caudiciforms native to South Africa. They belong to the Geraniaceae, or Geranium Family, and are closely related to the better known Pelargonium. Monsonia differs from Pelargonium primarily in having "actiniomorphic" flowers instead of zygomorphic ones. For non-botanists that means the flower of Monsonia are more or less circular and you could divide them into two equal halves no matter where you draw the line (like a pie or cake). Zygomorphic flowers are symmetrical in one plane only, just like a person's face. There is only one direction you could divide the flower in two with equal halves.
As for the plant themselves, they make wonderful additions to any caudiciform or winter growing succulent collection. The plants most commonly grown by cactus and succulent collectors are the woody Sarcocaulon group. They produce leaves when conditions are ideal for growth but drop them readily when the soil dries out, much in the same way as the unrelated Foquieria does. The flowers are usually white to pale pink, or even red, and an inch or two across. While called winter growers, it should be noted that some species, most notably Monsonia vanderietiae, are "opportunistic" growers that can grow most any time of year that it receives moisture. This is reflective of the Monsonia's habitat which is usually more arid than that of Pelargonium. However, that doesn't mean the plant will grow year round. During active growth water regularly, but provide little to no water when the plants decide to go dormant.
Photos in Cactus Chronicle:
Sarcocaulon/Monsonia flowers, Sarcocaulon piniculinum,
Sclerocactus - March 2015
Sclerocactus has 15 species. "Sclero" means "hard" and it refers to the hard dry fruit (most cacti have soft fleshy fruit). All species are native to the United States, with most species occurring in the lower Great Basin Desert of Nevada, Utah, Colorado, northern Arizona and northern New Mexico. Plants are small and covered in dense spines. Interestingly, these plants do not flower as well for us as they do in cold climates. Freezing weather helps signal to the plants to develop flower buds. In our nearly frost free climate they don't get the signal as clearly. Even more challenging for us is growing the plants from seed. They require a repeated freeze and thaw cycle to germinate. That is easy to get in its native range, but for us it means we need to keep the seeds in the freezer and periodically take them out to let them warm up.
They will grow just fine in our climate and it is always nice to have some cacti from America in your collection. Especially ones from our most overlooked desert (from a cultivation standpoint), the Great Basin.
Photo in Cactus Chronicle:
Sedum - March 2015
Whether chosen intentionally or not, this month's Sedum, shares an unusual trait (for cacti and succulents) with our cacti of the month, cold hardiness. At least for many of the most commonly grown species which can take snow and prolonged periods of subfreezing weather. Unlike this month's cacti, Sedum is a gigantic genus of 400-500 species. Native Sedum species can be found from Europe to Asia, Mexico to Madagascar, and America to Africa. Even though Sedum reaches the tropics, it still shows its preference for cooler climates as they tend to occur at higher elevations on mountains in those regions. This pattern is not unusual for plants primarily known from temperate climates as many genera of plants, such as Rhododendron, Conifers, and Violets, have a similar distribution.
Sedum belongs to the family Crassulaceae which includes many of our most popular succulents like Crassula, Echeveria, Aeonium, Kalanchoe, and Dudleya. While it is difficult to generalize for hundreds of different species, Sedum tends to form stems like Kalanchoe instead of rosettes like in Echeveria. The stems can be tall and straight, though more commonly the plants grow as a subshrub or groundcover such as S. dasyphyllum. One of the most interesting and popular species is S. morganianum, the Donkey Tail, known for its long hanging stems densely covered with fat cylindrical leaves.
DNA research on the relationships between species and genera of the Crassulaceae has shown Sedum species appearing in and amongst many different genera of the family. This means that Sedum is what taxonomists euphemistically call a "garbage can genus". Put simply, when there is a species of Crassulaceae that does not clearly belong to one of the other genera it usually gets called a Sedum by default, especially if it is a stem forming species that isn't a Kalanchoe. That leads to unrelated species being put in the same genus, which isn't acceptable from a scientific standpoint. Expect to see Crassulaceae specialists rearrange things in the future. For you, the succulent enthusiast, what it means is that you should keep the same labels you have on your plants for now, but in the future you may need to change some of them if calling the plant by its correct name is important to you. One exception to that is that one of the most commonly grown species, Sedum spectabile, has clearly been shown to belong to a new genus Hylotelephium.
Flowers in Sedum can be particularly showy, especially in the species that form large clusters of flowers. Many species are grown for the flowers, with the plant being a secondary consideration. Hylotelephium (formerly Sedum) spectabile is an exceptionally popular species grown in colder climates. It forms big clusters of flowers at the end of long stems and is very tolerant of moist growing conditions, allowing it to be grown in regular flower beds back east where it gets rained on and irrigated regularly. The popularity of this species has led to numerous cultivars being created with flowers colors ranging from red to pink to white, and even purple and salmon orange.
Did you know that California has 15 native species of Sedum? That makes it our third largest genus of succulents (including cacti) in our state. Only Dudleya and Opuntia have more native species. Some are tiny annuals while others are larger perennials that are quite succulent. Some, like S. albomarginatum, look so similar to Dudleya that you couldn't tell the difference without looking closely.
-- Kyle Williams
Photos in Cactus Chronicle:
Sedum albomarginatum, Sedum morganianum, Sedum nussbaumerianum
Sempervivum - March 2010
The genus Sempervivum is endemic to the mountainous regions of central and Southern Europe and the Mediterranean islands. The grow at anywhere from 3,000 to 8.000 feet and can therefore tolerate colder temperatures than other succulents. There are over 50 species and 3,000 cultivars. Sempervivum form smallish rosette clumps of many different sizes (1/2 inch to 3 inches), forms, textures, and colors. Like Aeoniums, Sempervivum produce a star-shaped flower stalk after which the rosette dies. Flower colors are typically red or pink. The rosette leaves may appear to be glossy or more matte. Hairy rosettes are found in the cultivars, where silver colored strands can occur along the leaf margins. Even more distinctive are the clumps of hair which can be found on the leaf tips. With some cultivars the effect is significant enough to produce a cobweb like appearance. Sempervivum are collected and prized for their forms and numerous colors.
-- Steve Frieze, February 2010
Photo in Cactus Chronicle:
Senecio and Othonna - January 2018, January 2012, January 2010
The two genera we are focusing on this month might not seem to have a lot in common, with one being a winter grower and the other a summer grower. The common thread is they are both members of the Daisy family, Asteraceae. The Asteraceae is the largest family of flowering plants with over 30,000 species. Only the Orchid family rivals it in size. As you’d expect in a family this large, species of Asteraceae can be found in every habitat all over the world. There are relatively few succulents for the size of the family, and the majority of these can be found in Senecio and Othonna.
Senecio is an enormous genus of over 1,250 species, making it the largest genus in the Asteraceae and among the top ten largest genera of all plants. While the genus is huge, only a fraction of them are true succulents. In fact, many Senecio are normal leafy herbs you’d see in a weedy field. However, it is the succulent ones that interest us. Among succulent Senecio there are two main “looks” or growth forms. The first are upright stem succulents with deciduous leaves (i.e. leaves that fall off after a short time). They often have bluish-green stems with interesting striped markings and generally (but not always) stay 1-2’ tall or less. You may see these plants listed under the old name “Kleinia” by some sellers, especially the species with bright red flowers. Some, like S. anteuphorbium get taller and make an interesting succulent shrub. The other type are trailing plants with thin stems and succulent leaves that make great hanging basket plants for shadier spots. These plants usually have small white flowers.
Othonna, with over 100 species, would be considered a large genus in most circumstances but seems tiny compared to Senecio! They are winter growing plants from the winter rainfall areas of Namibia and western South Africa. They are variable in form, with the most popular kinds having attractive caudiciform bases. Other types have fat elongated stems while others are geophytes which make annual stems that come up in the winter and die to the ground in the summer. Most make nice yellow daisy-like flowers. Cultivation of the woody species is very similar to Tylecodon or other woody winter growers, while the geophytic species can be treated similar to winter growing bulbs such as Albuca.
Photos in Cactus Chronicle -
Senecio rowleyanus, Senecio stapeliiformis
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Stapelia - September 2009
Stapelia and Caralluma are members of the Asclepiadaceae subfamily (formerly the family) of the Apocynaceae family (Bruyns, 2000). Both of these plants are described as stem succulents that belong to the Stepeliae tribe. They produce strong smelling flowers that are characterized as “carrion” with respect to their odor. The fragrance of the plants is linked to an intricate pollination mechanism that begins with the flies and other insects that are attracted to the flowers and that ultimately pollinate the flowers. The subfamily name is derived from the genus Asclepias (milkweeds). In addition to their unique floral fragrances, the flowers generated by these genera are also idiosyncratic with respect to their shapes, textures, and color combinations and are popularly called “starfish” flower plants.
Flowers are relatively short lived although in cultivation that have been known to sustain themselves for a few days. In good growing conditions, a sequential set of flowers are formed from the stems.
Propagation is relatively easily accomplished from cuttings or offsets that may be rooted in pumice. The use of a rooting compound such as Rootone (contains a fungicide) encourages successful propagation.
Stepelias and Carallumas should be grown in normal well drained cactus soil and watered thoroughly during the growing season. Mealy bugs can be an especially difficult problem with these two plants if an infestation takes hold. Preventive measures are a necessary and prudent step.
The natural habitat for Stapelias and Carallumas is Africa. Stapelias are typically found in the arid regions of tropical and southern parts of the continent. Over forty species can be located in Botswana, Zimbabwe, Namibia, and South Africa. They are also found in norther Zambia, southern Malawi, and central Mozambique
Steven Frieze, 2009
Photos in Cactus Chronicle:
Stapelia gigantea, Caralluma socatrana
Stenocactus - July 2017, August 2013
Stenocactus and Echinofossulocactus are the same genus. The name of this easy to grow and uniquely ribbed genus has been a subject of contention since the 19th century. The genus was originally described in 1841 by George Lawrence, but the description was invalid. It was re-described in 1898 by Karl Schumann. Various attempts to straighten out the names went on for the next hundred years. With blessings from the Committee for Spermatophyta, (no one else knows what it means either), Kew Gardens, and the International Cactaceae Systematics Group, the name Stenocactus seems to have finally triumphed.
Echino traces to Echinus, which is Latin for Hedgehog, a spiny porcupine-like rodent from Europe, and also, equally likely, and much closer in appearance, a spiny, edible sea urchin from the Mediterranean. Stenos is Greek for narrow, an obvious referral to the many narrow ribs on almost all of the species.
They are all spiny plants, collected much more for the appearance of the spines and the wonderful curved ribs than their flowers, although the flowers can be quite showy. All of the species (there are ten) are very variable, and as a result, there are numerous varieties and forms that can enhance any collection. Most of the species are reasonably small, flowering at two years, when only an inch or so in diameter. A good representative collection can be kept on a table.
Stenocactus are native to Central to Northern Mexican. The genus is closely related to Ferocactus, differing by the lack of nectar glands, the lack of a ring of hairs above the stamens, and size.
Stenocactus grow in grass lands, and need some protection from full sun. They are easy to grow, putting on most of their body weight each year in the early spring to summer. Plants growing outdoors will grow slowly during the winter using just the water from winter rains. It is important not to fertilize during the darker days of December, January or February, or etoliation or stretching of the body will occur. The narrow ribs, the wooly areoles, and the dense spines are an ideal habitat for mealy bugs. Frequent inspection of the plants will prevent them from spreading. Older plants sometimes get corky near the base. Keeping the plant in continuous growth delays this, but in some species the cork is inevitable.
Identifying the species of an Stenocactus is as difficult as identifying the genus is easy. For the most part, they tend to look alike, and there are far more names than there are species. However, a few species do stand out.
-- Kyle Williams, with Special Thanks to Tom Glavich
Photos in Cactus Chronicle:
Stenocactus (Echinofossulocactus) phyllacantha, Stenocactus (Echinofossulocactus) tricuspidatus,
Strombocactus - August 2014
Strombocactus is monotypic. The sole species of the genus is S. disciformis. Its native habitat is on limestone cliffs in central Mexico. This harsh, very dry, natural habitat is strikingly similar to that of Aztekium (albeit around 300 miles apart), and botanists at one time thought they belonged together in the same genus. All stay small enough to make nice potted specimens.
-- Kyle Williams
Photo in Cactus Chronicle:
Synadenium - July 2007
research in progress