Stenocereus beneckei
| Light | Full sun to bright light; acclimatise gradually to protect the waxy coating |
|---|---|
| Water | Moderately in the warm growing season; keep dry and cool in winter |
| Soil | Fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; happiest in warm, frost-free conditions (roughly USDA zones 9b–11) |
| Propagation | Cuttings (readily) and seed |
| Toxicity | Not known to be toxic; sap can irritate, so handle with care |
Stenocereus beneckei is a shrubby to sprawling columnar cactus from the hot, dry country of south-central Mexico, instantly recognised by the chalky, powder-white wax that coats its grey-green stems. That ghostly bloom, together with its relatively sparse spines and slender arching branches, has made it a prized oddity among collectors of columnar cacti. It belongs to the genus Stenocereus and was for many years placed in its own genus as Hertrichocereus beneckei.
Description
Stenocereus beneckei is a much-branched shrub, typically 1–2 m tall, that either stands loosely upright or sprawls, with slender stems that lean, arch and sometimes trail as they lengthen. The stems are grey-green and carry several prominent ribs, but their most striking feature is the dense, chalky-white waxy coating that overlays the epidermis, giving the whole plant a pale, frosted, almost ghostly look. This bloom rubs off easily where the plant is handled, revealing the darker skin beneath.
The areoles bear relatively few spines — typically a single stiffer, dark central spine with a handful of shorter marginals — so the pale ribbed stems remain the visual focus. Flowers are borne near the tops of the stems and open at night, sometimes staying open into the following morning; they are dull-coloured, brownish on the outside and whitish to cream within, rather than the bright hues of many relatives. These are followed by fleshy fruit that ripen reddish.
Distribution and habitat
The species is native to south-central Mexico, where it grows in hot, seasonally dry tropical deciduous woodland and scrub, on rocky slopes and cliffs at moderate elevations (roughly 1,200–1,400 m). It occurs in the states of Guerrero, Morelos, México and Puebla. It is a plant of warm, sun-baked slopes with a pronounced dry season, conditions that are worth keeping in mind when growing it.
Like all cacti, Stenocereus beneckei is listed on CITES Appendix II, which regulates international trade; it has been assessed by the IUCN as Near Threatened.
Cultivation
Stenocereus beneckei is a warmth-loving cactus that rewards a bright, sunny position and a strongly free-draining, mostly mineral mix. Water moderately through the warm months once the soil has dried, then keep the plant dry and rather cool over winter; like most desert columnars it resents wet, cold roots and will rot if kept soggy.
The prized white waxy coating is delicate. It is a natural bloom produced by the plant and cannot be restored once wiped away, so handle stems as little as possible and avoid overhead watering that streaks the bloom. Bright light helps the plant produce a good, even coating; too little light gives thin, etiolated growth that colours up poorly. See Watering and Repotting for general technique.
Propagation
The species roots readily from stem cuttings: take a length of stem, let the cut end callus for a week or two in a dry, shaded spot, then set it in a gritty, barely-moist mix until roots form. It can also be raised from seed sown on a warm, mineral surface, though seedlings are slower to reach display size.
Common problems
- Rot — the usual result of overwatering or a poorly-draining mix, especially in cool weather; stems soften and discolour from the base.
- Lost bloom — the white wax rubs off with handling and does not grow back on that spot; plan your handling and watering to preserve it.
- Etiolation — too little light produces thin, pale, weakly-coated growth that flops.
- Pests — mealybugs (white fluff in the areoles, easily confused with the natural wax) and red spider mites are the most likely troublemakers.
See also
- Stenocereus — the genus overview
- Soil and potting mix · Watering · Propagation — cuttings · Propagation — seed · Pests and diseases