Euphorbia francoisii
| Light | Bright, indirect to lightly filtered sun; strong light intensifies leaf colour |
|---|---|
| Water | Moderate in growth; let the top of the mix dry between waterings, drier in winter |
| Soil | Fast-draining, gritty mineral mix (see Soil and potting mix) |
| Temperature | Warm; keep above about 10 °C, no frost (roughly USDA zones 10–11) |
| Propagation | Seed (needs both sexes); also cuttings and grafting |
| Toxicity | Toxic — caustic milky latex, irritant to skin, eyes and if ingested; keep away from pets and children |
Euphorbia francoisii is a small, slow-growing, caudex-forming succulent from southeastern Madagascar, grown almost entirely for its extraordinarily colourful, patterned leaves rather than its tiny flowers. A member of the huge genus Euphorbia, it has been bred and selected intensively — especially by hobbyists in Thailand — into a dazzling range of foliage forms marbled and edged in green, cream, pink, silver, bronze and near-black.
Description
Euphorbia francoisii is a dwarf plant that builds a short, thickened stem or partly buried caudex from which a low rosette of leaves emerges at the top. The leaves are the whole attraction: often spoon-shaped with wavy or crinkled margins, and coloured in bands, marbling and contrasting edges that vary enormously from plant to plant. Selected clones can be strikingly patterned, and leaf colour typically deepens in bright light and cooler conditions.
Like all euphorbias, its true flowers are tiny and enclosed in specialised cup-like structures called cyathia, which are small and unshowy compared with the foliage. The species is dioecious, meaning individual plants are either male or female, so both sexes are needed to set seed. As with the rest of the genus, cut or broken tissue exudes a milky white latex.
Distribution and habitat
The species is native to southeastern Madagascar, where it grows as a small understorey succulent in seasonally dry, warm conditions, often in leaf litter and shade rather than in full exposure. As with many Madagascan euphorbias, wild habitat is limited and collection pressure is a conservation concern; all succulent members of the genus Euphorbia, this species included, are listed under CITES Appendix II. Fortunately, nursery- and hobby-propagated plants are widespread in cultivation, so there is no need to source wild material.
Cultivation
Euphorbia francoisii is a warmth-loving plant that dislikes cold and wet feet. Grow it in a very free-draining, mostly mineral mix in a snug pot, and give it bright light — filtered or indirect sun suits it best, and good light keeps the leaf colours saturated. Water moderately while it is in active growth, letting the surface of the mix dry between waterings, then ease right back through the cooler, darker months when the plant slows or partly drops its leaves.
Keep it reliably above about 10 °C and never let it freeze. Because it is small and shallow-rooted, it appreciates careful Watering and does not need frequent Repotting. Always handle the plant with care: the latex is a skin, eye and mucous-membrane irritant, so wear gloves when taking cuttings and wash up afterwards.
Propagation
Several methods work. Seed gives the most variation and is how new colour forms arise, but because the species is dioecious you need both a male and a female plant flowering together, with hand-pollination to set the explosive capsules. Cuttings can also be rooted: allow the cut end to dry and callus for several days first to stop the latex flow, then set it in a barely moist gritty mix. Choice clones and weaker seedlings are sometimes grafted onto a more vigorous Euphorbia rootstock to speed them up. See Propagation — seed and Propagation — cuttings for general technique.
Cultivars
E. francoisii has been selected primarily for foliage, and a great many named and unnamed colour forms circulate in the hobby, ranging from marbled greens and creams to intense pinks, bronzes and near-blacks. It also hybridises readily with related dwarf Madagascan euphorbias, and much of what is sold under this name in collections is the product of such selective breeding. Because these traits are maintained through seed selection and vegetative propagation, colour and pattern can vary between individual plants.
Common problems
- Rot — the commonest killer, almost always from a heavy mix or overwatering, especially in winter; the caudex or stem base softens and discolours.
- Faded colour and stretching — too little light leaves the foliage dull and etiolated; move to brighter light to restore contrast.
- Cold damage — chilling below its comfort range causes leaf drop and dieback.
- Pests — mealybugs (white fluff in the crown and on roots) and spider mites are the usual offenders; see Pests and diseases.
See also
- Euphorbia — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Propagation — cuttings · Pests and diseases