Schlumbergera russelliana
| Light | Bright, filtered light; no harsh direct sun (an epiphyte used to dappled forest shade) |
|---|---|
| Water | Regular through active growth; ease off after flowering, never let it sit bone-dry for long |
| Soil | Loose, open, humus-rich epiphyte mix (see Soil and potting mix) |
| Temperature | Warm growing season; a cool, short-day autumn to set buds; keep above freezing |
| Propagation | Stem-segment cuttings; grafting to build size quickly |
| Toxicity | Non-toxic to cats and dogs |
Schlumbergera russelliana is a Brazilian epiphytic cactus with flattened, scalloped stem segments that trail and arch from the mossy branches and rock ledges it calls home. Together with Schlumbergera truncata it is one of the two wild species behind the familiar Christmas cactus hybrids of the houseplant trade, and its later, gently drooping flowers earn it the name true Christmas cactus.
Description
Schlumbergera russelliana is a leafless cactus whose "leaves" are in fact flattened green stem segments (cladodes) joined end to end into arching, eventually pendent chains. Each segment is oblong with shallow, rounded scallops along the margins — noticeably softer and less toothy than the sharply pointed segments of Schlumbergera truncata, a difference that helps tell the two species and their hybrids apart.
Flowers open from the tips of the segments and hang more or less symmetrically, with tiers of pink to magenta tepals and a projecting bundle of stamens. Compared with S. truncata, the blooms are radially balanced (rather than tilted upward) and tend to arrive later in the season — closer to true midwinter in the northern hemisphere, hence "Christmas" cactus. As with other members of the genus, the flowers are triggered by shortening days and cooler nights.
Distribution and habitat
The species is native to the Serra dos Órgãos and neighbouring mountains of Rio de Janeiro state in southeastern Brazil, where it grows as an epiphyte on tree branches and as a lithophyte on shaded, mossy rock in humid Atlantic Forest. In these cloud-forest conditions it enjoys constant humidity, filtered light and roots that are never waterlogged but rarely fully dry — a useful picture to keep in mind when growing it.
Cultivation
Grow Schlumbergera russelliana as a forest cactus rather than a desert one. It wants an open, humus-rich mix that holds a little moisture yet drains freely, bright but filtered light, and steady warmth and humidity through its growing season. Water regularly while it is in active growth and flower, then reduce watering for a rest afterwards — but avoid the long, bone-dry droughts suitable for desert cacti. See Watering and Repotting for general technique.
To bloom well the plant needs a cool, short-day autumn: several weeks of long nights and cooler temperatures will set the buds. Once buds have formed, avoid moving or rotating the plant, as sudden changes in light or temperature can cause bud drop. It makes an excellent hanging-basket subject, where its trailing segments and pendent flowers show to best effect.
Propagation
Propagation is easy from stem-segment cuttings: detach a short chain of two or three segments, let the cut end callus for a day or two, then root it in a barely moist, open mix. Cuttings root readily and quickly build into flowering plants. Growers also graft segments onto an upright rootstock such as Pereskia or Hylocereus to create a fast, tree-form "standard." Seed is possible but slow and mainly of interest to hybridisers. See Propagation — cuttings for a full walkthrough.
Cultivars
Pure S. russelliana is grown mostly by collectors and by breeders working on the genus; the plants most people own are hybrids. Crossing this species with Schlumbergera truncata produced the horticultural group long known as Schlumbergera × buckleyi, the classic winter-flowering Christmas cactus sold in a wide range of pinks, reds, whites and bicolours. See the Schlumbergera genus page for an overview of the cultivar and hybrid groups.
Common problems
- Bud drop — the commonest frustration; usually caused by moving the plant, draughts, sudden temperature swings, or letting it dry out while in bud.
- Rot — overwatering or a dense, airless mix causes segments to yellow, redden or go limp and mushy at the base.
- Poor flowering — too little cool, short-day autumn conditioning, or too much artificial light at night, prevents bud set.
- Pests — mealybugs (white fluff in the segment joints) and root mealybugs are the usual culprits; see Pests and diseases.
See also
- Schlumbergera — the genus overview
- Schlumbergera truncata — the other parent of the Christmas-cactus hybrids
- Propagation — cuttings · Grafting · Soil and potting mix · Watering · Repotting · Pests and diseases