Selenicereus grandiflorus
| Light | Bright light with some shade; a good climber for a warm greenhouse or bright indoor spot |
|---|---|
| Water | Regular during the growing season; reduce in winter but avoid a completely bone-dry rest |
| Soil | Rich but free-draining mix with added grit (see Soil and potting mix) |
| Temperature | Keep above freezing; happiest in warm, frost-free conditions (roughly USDA zones 10–11) |
| Propagation | Stem cuttings (easy); also seed |
| Toxicity | Not among the plants commonly listed as toxic to pets, but the stems and flowers have a history of medicinal use and contain pharmacologically active compounds — not a plant to eat; keep out of reach of pets |
Selenicereus grandiflorus is a scrambling, climbing cactus grown for its enormous, powerfully fragrant flowers that open for a single night. Its slender, ribbed stems clamber over rocks and through shrubs by means of aerial roots, and each summer they produce huge creamy-white blooms ringed with slender golden outer petals and carrying a rich, sweet vanilla-like scent — a spectacle that earned it the common names queen of the night and night-blooming cereus and made it a treasured conservatory plant and a classic of nineteenth-century folk medicine.
Description
Selenicereus grandiflorus is a sprawling, epiphytic and lithophytic cactus rather than a neat globular plant. Its stems are thin, cylindrical and ribbed, dark green, branching freely and reaching considerable lengths as they scramble upward. Small clusters of short spines sit at the areoles, and along the stems the plant throws out aerial roots that anchor it to bark, walls and rock.
The flowers are the whole point of the plant. They are among the largest of any cactus — broad, funnel-shaped and creamy white, surrounded by a ring of narrow golden-brown to yellow outer segments that give a starry, sunburst effect. They open after dark, release an intense sweet fragrance said to carry across a room, and are usually spent by morning. Blooming is concentrated in the warmer months, and a mature, well-grown plant may open several flowers over a season.
Distribution and habitat
The species is native to the Caribbean and parts of Central America, where it grows in warm, humid, frost-free conditions. In the wild it behaves as a climber and rock-dweller, threading through scrub and over limestone and tree trunks in dappled light rather than sitting in full desert sun. It has long been cultivated far beyond its native range and has naturalised in some warm regions.
Note that "queen of the night" and "night-blooming cereus" are loose common names shared by several unrelated night-flowering cacti (various Selenicereus, Epiphyllum and Cereus relatives), so plants sold under those names are not always this species.
Cultivation
Selenicereus grandiflorus is an easygoing plant for a warm, bright spot, and forgiving of a little neglect once established. Because it is a climber, give it room and something to climb — a trellis, moss pole or the framework of a greenhouse — and let the aerial roots take hold. Grow it in a rich but free-draining mix with added grit, and water regularly through the growing season, easing off in winter without letting it dry out as harshly as a desert cactus would tolerate.
Bright light encourages flowering, but protect the stems from the fiercest direct sun, which can scorch them; the plant naturally grows in partial shade. Warmth, maturity and a slightly cooler, drier winter rest all help bring on the celebrated blooms. See Watering and Repotting for general technique.
Propagation
The easiest method is stem cuttings. Sections of stem root readily once the cut end has been allowed to callus for a few days, then potted into a gritty, barely-moist mix — an ideal way to share this plant and to build up a fuller specimen. It can also be raised from seed, though cuttings are quicker and reach flowering size sooner. See Propagation — cuttings and Propagation — seed for full walkthroughs.
Common problems
- Rot — the usual cause of loss, from a soggy mix or cold, wet winter conditions; stems soften and blacken.
- No flowers — most often down to immaturity, too little light, or no seasonal change; young plants and heavily shaded ones are reluctant to bloom.
- Scorch — harsh midday sun can bleach or brown the stems of a plant used to dappled light.
- Pests — mealybugs (white fluff in the areoles) and scale are the most common, along with the occasional spider mite in hot, dry air. See Pests and diseases.
See also
- Selenicereus — the genus overview
- Propagation — cuttings · Soil and potting mix · Watering · Repotting · Pests and diseases