Dracaena hanningtonii
| Light | Bright light to full sun; tolerates some shade but colours best in strong light |
|---|---|
| Water | Sparingly; let the soil dry completely between waterings, near-dry in winter |
| Soil | Very free-draining, gritty mineral mix (see Soil and potting mix) |
| Temperature | Warmth-loving; keep above about 10 °C, USDA zones 10–11 |
| Propagation | Division of the rhizome and offsets; leaf cuttings; seed |
| Toxicity | Mildly toxic to cats and dogs (contains saponins) |
Dracaena hanningtonii — long known and still widely sold as Sansevieria ehrenbergii — is a robust East African succulent commonly called the blue sansevieria or sword sansevieria. Instead of forming a rosette, its thick, tapering, blue-green leaves grow in two opposite ranks along a short rhizome, so a mature clump fans out in a single flat plane like the spokes of an open hand. It is one of the leaf-succulent "snake plants" — the former genus Sansevieria, now merged on DNA evidence into the broader Dracaena genus.
Description
Dracaena hanningtonii produces stiff, upright to gently arching leaves that are thick, laterally flattened and deeply channelled (grooved) down the upper face, rounded on the back. They are a distinctive waxy blue-green, often edged with a fine reddish-brown or white margin, and taper to a hard point. The two-ranked (distichous) arrangement is the plant's signature feature: rather than spiralling into a rosette, successive leaves emerge on opposite sides of the growing point, building a flat, fan-shaped clump that spreads slowly by a stout underground rhizome.
Over time a colony forms a low thicket of these fans, and older leaves can reach a substantial size in ideal conditions. Flowering is infrequent in cultivation; when it occurs the plant sends up a slender spike of small, pale, tubular flowers that open toward evening and are lightly fragrant.
Distribution and habitat
The species is native to the dry country of East Africa, ranging through parts of Kenya, Tanzania, Ethiopia, Somalia and neighbouring arid regions. It grows in hot, seasonally dry bushland and semi-desert, typically in stony or sandy ground among thornscrub, where it endures long droughts, strong sun and poor soils. These origins explain its heat tolerance and its dislike of prolonged damp.
Cultivation
Blue sansevieria is undemanding and well suited to growers who tend to underwater. Plant it in a very free-draining, mostly mineral mix and give it the brightest position you can — it takes full sun happily and keeps its best blue colour and compact habit there, though it will cope with light shade. Water thoroughly only once the soil has dried right through, and cut back sharply in winter, keeping the plant nearly dry and above roughly 10 °C.
The commonest cause of loss is rot from overwatering or a soggy mix, so err on the side of neglect. The rhizome spreads sideways, so a wide, shallow container suits it; see Watering and Repotting for general technique. In cold climates grow it as a houseplant or move it under cover before the first frosts.
Propagation
The easiest and most reliable method is division: lift an established clump and separate the rhizome so each piece carries a fan of leaves and its own roots, then pot up and keep barely moist until re-established. See Propagation - offsets and Propagation - cuttings. Leaf cuttings are also possible — a healthy leaf can be cut into sections and set upright in gritty compost to root — though variegated or specially selected plants are best divided, as leaf cuttings usually revert to the plain green form. Seed is used less often and is slower; see Propagation - seed.
Common problems
- Rot — soft, discoloured leaf bases or a mushy rhizome, almost always from overwatering or a slow-draining mix.
- Cold damage — translucent, water-soaked patches after exposure to low temperatures; the plant is not frost-hardy.
- Pests — mealybugs (white fluff tucked into leaf junctions) and occasionally spider mites in hot, dry air; see Pests and diseases.
- Dull, floppy growth — a sign of too little light; move it somewhere much brighter to restore firm, blue-toned leaves.
See also
- Dracaena — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation - offsets · Propagation - cuttings · Pests and diseases