Senecio mandraliscae
| Light | Bright light to full sun; colour best in strong light |
|---|---|
| Water | Occasional deep soak, then dry out fully; nearly dry in winter |
| Soil | Fast-draining, gritty succulent mix (see Soil and potting mix) |
| Temperature | Best above freezing; hardy in USDA zones 9b–11, briefly to the high 20s °F |
| Propagation | Stem cuttings (very easy); division |
| Toxicity | Mildly toxic if eaten; sap may irritate skin |
Senecio mandraliscae — now more correctly placed in the genus Curio as Curio talinoides var. mandraliscae — is a low, spreading succulent grown for its striking powder-blue, finger-like leaves. Widely sold as blue chalksticks or blue fingers, it is one of the most popular succulents for drought-tolerant groundcover and colour contrast in xeriscape and rock gardens.
Description
Senecio mandraliscae forms a sprawling, low mound of trailing to semi-upright stems that root where they touch the soil, spreading steadily into a dense mat. The plant typically reaches around 30–45 cm tall and spreads considerably wider over time.
Its most distinctive feature is the foliage: slender, cylindrical, slightly upcurved leaves 5–10 cm long, tapering to a soft point and held like clusters of upright fingers along the stems. A pale blue-grey waxy bloom (farina) coats the leaves, giving the whole plant its characteristic chalky, ice-blue colour — most intense in bright light and on new growth. Small, dull white flower heads appear in summer, but the plant is grown almost entirely for its foliage rather than its bloom.
The very similar Curio repens (also called blue chalksticks) is more compact with shorter, plumper leaves; the two are often confused in the trade.
Distribution and habitat
The species is native to South Africa, where its relatives grow in dry, open, well-drained sites. In cultivation it has become a mainstay of Mediterranean-climate landscaping worldwide — particularly in California, the American Southwest, Australia and southern Europe — valued for thriving in poor soils, heat and drought.
Cultivation
Senecio mandraliscae is one of the easiest succulents to grow and a good choice for beginners. Give it a very free-draining, gritty mix and as much sun as possible; strong light keeps the growth compact and deepens the blue colour, while too little light causes stems to stretch and flop, and the blue to fade toward green.
Water deeply but infrequently, letting the soil dry out completely between waterings, and cut back to almost nothing in winter — like most succulents it rots quickly if kept wet in cold conditions. See Watering for general technique. As a groundcover it is nearly self-maintaining: trim back leggy or wandering stems to keep the planting tidy, and use the trimmings as cuttings.
It tolerates light frost once established but can be damaged by hard freezes; in colder regions grow it in containers that can be moved under cover, and repot every few years as the mat crowds its pot.
Propagation
Propagation could hardly be easier. Take stem cuttings of any length, let the cut ends callus for a day or two, then lay or insert them in gritty soil; they root readily in warm weather. Because the trailing stems root as they spread, established clumps can also simply be divided and replanted. Cuttings are the standard method, and one plant quickly yields enough material to fill a bed.
Common problems
- Rot — the main killer, caused by overwatering or poorly draining soil, especially in winter; stems go soft, mushy and translucent.
- Etiolation and flopping — in too little light the stems stretch, lean and open up in the middle, losing the tidy blue mound; cut back and move to brighter light.
- Loss of blue colour — the powdery bloom rubs off with handling and fades in shade; new growth in strong sun restores it.
- Pests — mealybugs can hide among the crowded stems and root zone; aphids occasionally attack flower stalks.
See also
- Curio — the genus overview
- Propagation — cuttings · Soil and potting mix · Watering · Repotting · Pests and diseases