Peniocereus viperinus aka Peniocereus Viperinus

Peniocereus viperinus is a shrubby cactus with long, thin branches. It belongs to the cactus family, Cactaceae. Its native range covers Morelos, Puebla, and Oaxaca in Mexico. It grows in dry scrub and tropical forests that shed leaves. It also occurs in stands of tall cacti called cardonales. Wild plants grow at 3,281–5,577 feet [1,000–1,700 metres] above sea level. Growers have long known it as Wilcoxia viperina.

Plants can reach about 10 feet [3 metres] tall. Their many branches trail or scramble rather than stand upright. Thick, fleshy roots store starch beneath the ground. New growth develops when water becomes available. LLIFLE reports that aboveground parts die during the dry season. The grey-green stems bear fine hairs that feel like velvet. They are less fleshy than those of most cacti. Each stem has six to ten low, faint ribs. Small areoles carry dark grey to black spines. Some spines lie flat against the stem. Older stems lose their spines over time.

Flowers open during the day in summer. They grow from the sides of the stems. Their colour ranges from vivid pink to shiny red. Each can reach 0.30 feet [0.09 metres] long. The flower tube and ovary bear black bristles and white wool. The fruit has a pear-like shape and contains smooth seeds. People gather the fruit from wild plants and eat it raw. Useful Tropical Plants lists no known hazards. This does not establish safety for pets or every plant part. The same source records no known medicinal uses.

In cultivation, this cactus needs bright shade or some sun. Use a loose mix with ample leaf mould and good drainage. Enough water in warm weather supports fast growth. The thin stems need support as they lengthen. Cold tolerance is limited, so winter warmth matters. LLIFLE recommends a winter minimum near 50°F [10°C]. It reports brief survival at 32°F [0°C]. Growers can raise new plants from cuttings or seed.

Its partly upright form suits the middle foreground of planting beds. It also takes little space when grown in greenhouse pots. People grow it for ornament as well as fruit. Useful Tropical Plants reports an IUCN status of Least Concern. Farming and cattle ranching still damage its wild habitat. Some populations occupy protected land, but others occur in small, isolated groups.