Cereus stenogonus
| Light | Full sun to bright light; tolerant of strong sun once established |
|---|---|
| Water | Moderate in summer growth; keep dry and mostly rainless through winter |
| Soil | Free-draining mineral-rich mix (see Soil and potting mix) |
| Temperature | Keep above freezing; USDA zones 9b–11, brief light frost tolerated on established plants |
| Propagation | Seed and stem cuttings |
| Toxicity | Non-toxic to cats and dogs |
Cereus stenogonus is a tall, tree-like columnar cactus from the lowlands of Paraguay, northern Argentina and adjacent parts of Bolivia and Brazil. It is prized for its striking blue-green to glaucous stems, which carry only a few deep, sharply-angled ribs that give the column a bold, sculptural profile. Like other members of the genus Cereus, it is a vigorous, easy-going grower and a large plant in time.
Description
Cereus stenogonus grows into a branching, tree-like plant that can reach several metres tall in habitat, eventually forming a short woody trunk with a candelabra of upright arms. The stems are notably thick and coloured an attractive blue-green with a waxy, glaucous bloom that is heaviest on fresh growth.
The species is distinguished within the genus by its low number of ribs — often only four or five — which are prominent, deep and rather thin-edged, giving the stem a strongly angled, almost winged cross-section (the epithet stenogonus refers to these narrow angles). Areoles along the rib margins are spaced well apart and bear short, modest spines rather than the dense armament of many desert cacti.
Large flowers open along the upper stems in the warmer months. As is typical for Cereus, they are funnel-shaped and sizeable — around 20 cm long, with a long, slender tube — but, unusually for the genus, they are a distinct pink to rose rather than white, opening at night. Fertile flowers are followed by fleshy red fruit.
Distribution and habitat
The species is native to the Gran Chaco and surrounding lowlands of Paraguay, northern Argentina and adjacent parts of Bolivia and Brazil. It grows in seasonally dry woodland and scrub, typically in warm, frost-free conditions with a distinct wet summer and drier winter. In these habitats it often stands as an emergent column above lower thorny vegetation.
Cultivation
Cereus stenogonus is one of the more forgiving columnar cacti and grows readily for beginners. Give it a large, deep pot or an open bed and a free-draining, mineral-rich mix that never stays wet. In the growing season it appreciates more water and feeding than a typical desert cactus — this fuels its fast, thick growth — but the soil should still dry appreciably between waterings. See Watering for general technique.
Grow it in full sun to very bright light to keep the stems compact, blue and upright; too little light causes thin, etiolated growth that leans and loses colour. Keep the plant largely dry through winter and protect it from hard frost. Established plants tolerate a brief, light freeze, but young or well-watered stems are easily damaged. Large specimens grow quickly and become heavy, so plan for Repotting into stable, weighty containers.
Propagation
The species is easily raised from seed, which germinates freely in warm, humid conditions. It is just as readily grown from stem cuttings: a severed section is left to callus for several days in a dry, shaded spot, then set on a barely-moist mineral mix to root.
Common problems
- Rot — the usual cause of loss, from a mix that holds water or from watering during cold, dark spells; stems soften and discolour, often from the base.
- Etiolation — insufficient light produces pale, narrow, weak growth and loss of the blue colour and bold ribbing.
- Frost damage — scarring, corky patches or collapse on stems exposed to hard or prolonged freezing.
- Pests — mealybugs (white fluff in the areoles) and scale are the most common; watch also for red spider mites in hot, dry, still air. See Pests and diseases.
See also
- Cereus — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — cuttings · Propagation — seed