Mother-In-Law Tongues and Others—Sansevieria

For an all too familiar seeming genus of plants (the old common name, mother-in-law tongue, implying that you can't get rid of them). Sansevieria nonetheless contains a large number of unfamiliar and very interesting species. The genus has wandered from family to family over the years, starting out as Liliaceae, then Agavaceae, and finally (at least for the moment) showing up in the fairly newly established family Dracaenaceae. This taxonomic migration reflects the close resemblance of these strictly Old World plants to the New World agave family. Dracaenas, familiar house and office plants, include a few rarely seen species (some in the UCBG collection) from places such as southwest Arabia and the island of Socotra that appear remarkably similar to arborescent, xerophytic Yucca species. A few sansevierias resemble agaves or yuccas, and they occupy somewhat equivalent ecological niches in their native habitats of eastern African and surrounding regions.
Essentially only two forms of Sansevieria, both only semi-succulent, constitute the vast majority of the plants found in cultivation. One of these is Sansevieria trifasciata, with long, narrow, sword-shaped, upright leaves. Since the plants have been grown for so long, numerous forms and cultivars have been selected out, such as the cultivar ‘Laurentii,’ with distinct banded marking and a yellow leaf margin, a central component of innumerable dish gardens and indoor plant displays. Other forms of Sansevieria trifasciata, however, have managed to keep from become living clichés. Among these, ‘Bantel's Sensation’ often attracts attention with its white leaves marked with linear green streaks and narrow green margins. As is the case with many highly variegated plants, it grows slowly enough to have remained somewhat uncommon. Some growers specialize in odd forms of S.fasciata, or the still confused plant called S. hahnii, of uncertain horticultural origin. Sansevieria hahnii resembles a small, spineless Agave and grows into a compact rosette of flattened leaves. ‘Golden Hahnii’ is a common form with golden-yellow leaf margins; ‘ Loop 's Pride,’ much less common, forms small rosettes that are almost black when well grown. Other forms are rarer still, very slow growing, and command extremely high prices.
The other sansevierias, rarely encountered in the general nursery trade, exhibit a considerable diversity of forms and often a great deal more developed degree of succulent modification. Many species form tight rosettes, usually offsetting from close to the surface rhizomes. Of these, some remain quite small, with rosettes no more than four or five inches across, including Sansevieria subspicata, S. parva, or the relatively uncommon S. aethiopica. These three have relatively broad leaves with soft tips; others with this growth form, such as S. phillipsiae may have narrow leaves that end in very sharp points, and sometimes have rosettes over a foot in diameter. In nature these plants often cluster around the bases of acacia trees in the seasonally dry East African plains. Another growth form, typified by Sansevieria grandis, consists of rosettes made of broad, upward pointing, elongated leaves that ultimately take on the shape of a huge, openwork vase. A third form, including species such as Sansevieria stuckyi and S. cylindrica, sends out thickly terete (cylindrical) leaves that point upright several feet into the air. In other species the leaves are somewhat spoon shaped, broadening into ovals after a thin stem-like base, while still others make columns of distichous (two-ranked) leaves like pillars made of stacks of cow horns. These distichous species can become quite tall, or, as in the case of Sansevieria ehrenbergii or S. robusta, the individual leaves will become large and massive, the adult plant looking like a many fingered, outspread hand or an open fan.
A further odd feature of many sansevierias is that immature plants may look entirely distinct from adult forms. A good example of this is the species formerly called Sansevieria singularis, now S. fischeri. When young the plants make clusters of rosettes of thick, downward curving, channeled leaves of an interesting, mottled green color. A plant with multiple rosettes may be quite large and seem full grown, but at some point the growths will change to erect single leaves only, and a mature specimen will consist of a number of these very thick, very large leaves, up to several feet tall, protruding out of the ground with no sign of the rosettes from which they began.
Vaguely similar in appearance, though never forming rosettes, is Sansevieria hallii, introduced as Sansevieria ‘Baseball Bat.’ These plants consist of several individual leaves, connected by an underground rhizome and looking more like a baseball bat sawed down the middle than a cylinder, slowly poking their way into the air. Another unusual species, S. pinguicula, from Kenya, slowly makes clumps of pointed, very thick leaves that resemble a choice miniature Agave, except that the rosettes tend to become airborne, raised up by clusters of thickened roots. Sansevieria kirkii var. pulchra, with elongated, upright growing leaves, has a striking pattern of mottled cross-hatchings, and in the best clones is a mixture of pink and gray with hardly a trace of green to be seen. Still rare and coveted, S. eilensis, from Somalia, produces occasional upright leaves about the size and shape of a finger from its subsurface rhizome, while the plant known as S. horwoodii (called by some Sansevieria ‘Horwood’ and possibly a form of S.forskaliana,), has flattened leaves of great thickness, giving it, too, an extremely distinctive look.
Many sansevierias are close to indestructible. They will tolerate much lower light than other succulents, or almost any other plants. They will survive with almost any soil mix, and endure neglect and abuse without complaint. Under ideal conditions they should receive a little morning sunlight or bright indirect light, water about once a week--less often (every three weeks or so) in winter--and will thrive slowly in either a standard succulent mix or a slightly richer soil. A few are touchier. Sansevieria pinguicula will rot if water remains in its rosettes; it also will do better with slightly leaner soil and somewhat brighter light. S.eilensis can be quite difficult to grow, and some people keep it in beds heated by electric cables to keep it from rotting off.
All in all, Sansevieria is an interesting genus, with plants ranging from ones you can't kill, to ones you can't find, or can barely keep alive in ideal circumstances. The Garden has a good collection of the plants (several on display in the Arid House), with a number of unidentified species, many from Kenya . We always have some to sell at sales, often located in the shade under the tables.