Lepismium
Lepismium is a genus of South American epiphytic cacti, closely allied to (and once lumped in with) Rhipsalis. They grow not in the ground but perched on tree branches and rock faces in humid forest, sending out long, trailing or arching stems that make them popular as easy-care hanging-basket plants.
Description
Members of Lepismium are shrubby epiphytes with slender, pendent stems that branch freely and cascade over the edge of a pot or basket. Depending on the species the stems may be cylindrical, sharply three- to four-angled, or flattened and leaf-like, and they are segmented into long joints. Unlike the desert cacti most people picture, these plants carry few or no proper spines; instead their areoles sit in small notches along the stem margins, often marked by a little wool or a few fine bristles.
The flowers are small, borne singly or in clusters directly from the areoles along the stems, and range from white and cream to pink or reddish. They are followed by small, rounded, berry-like fruits — translucent white, pink or wine-red — that give the plants a decorative second season. A useful way to tell Lepismium from close relatives is that the flowers and fruit tend to sit in a slightly sunken areole, partly embedded in the stem.
Distribution
The genus is South American, centred on the humid forests of Brazil and extending into Argentina, Uruguay, Paraguay and Bolivia. Plants grow as epiphytes on tree trunks and branches, or as lithophytes on shaded, mossy rocks, in the dappled, humid conditions of the forest canopy and understorey — a habitat that explains their preference for shade, moisture and airy, organic footholds rather than baking sun and dry mineral grit.
Notable species
- Lepismium cruciforme — variable, angled stems that flush attractive pink or purplish tones in bright light; one of the most commonly grown.
- Lepismium houlletianum — long, flat, leaf-like stems with finely toothed margins, nicknamed the snowdrop cactus.
- Lepismium lumbricoides — slender, worm-like cylindrical stems that trail densely.
- Lepismium warmingianum — sharply angled, winged stems with a pleasingly geometric look.
Note that the boundaries of Lepismium have shifted over time, and several plants have moved between this genus and Rhipsalis, Pfeiffera and others; older nursery labels may not match current botanical names. For example, the plant long grown as Lepismium bolivianum (older name Rhipsalis boliviana) is now usually placed in Pfeiffera.
Cultivation
As forest epiphytes, Lepismium species want almost the opposite of what typical desert cacti need. Grow them in bright but indirect light or light shade — direct midday sun scorches the stems, though a little brightness brings out red and purple stem colour. Use an open, moisture-retentive, organic mix with plenty of bark, coir or perlite for air around the roots, rather than a pure mineral grit; some growers mount them or grow them much as they would an orchid.
Water more generously than you would a globular cactus, keeping the mix lightly moist through the warm growing season and letting it dry only partway between waterings; ease off in winter but never bake them bone-dry for months. They appreciate humidity and good airflow, and reward a feed with dilute fertiliser while in active growth. A hanging basket or tall pot shows off their trailing habit best. See Watering and Repotting for general technique.
Propagation is easy from stem cuttings: a segment or two allowed to callus briefly and set on a moist, open mix will root readily, which is how most named plants are shared. Fresh seed also germinates well in warm, humid conditions. See Propagation — cuttings and Propagation — seed.
Hobby notes
Lepismium are forgiving, fast-growing plants well suited to beginners and to anyone with a bright bathroom, shaded porch or humid windowsill. They mix happily in collections alongside Rhipsalis, Schlumbergera (Christmas cactus) and Hatiora, all of which enjoy similar epiphyte care. Because the genus has been repeatedly reshuffled by botanists, the same plant may circulate under several names — a good reason to buy from growers who know their material and to enjoy the plants for their form rather than fretting over labels.
See also
- Rhipsalis — the closely related epiphytic genus
- Schlumbergera · Hatiora — other forest cacti with similar care
- Soil and potting mix · Watering · Propagation — cuttings · Repotting