Stenocereus Pruinosus Flowers

The Cactus

• The cactus is a ribbed cactus whose new growth is the site of the flowers. The plant has six to 10 ribs with aureoles from which spines and the flowers emerge. The spines are arranged in groups of 28 and start out rose to magenta, then mature to a light gray or white. Stenocereus may produce numerous branches or it may grow as a single column. The color is gray-green and has a whitish cast from waxy secretions. The branches are narrower at the base and will show distinct growth notches.

The Flowers

• From the aureoles on the ribbed part of the cactus, the flowers bloom. They are usually single and slightly tubular. Each aureole only produces one flower which stays open day and night until pollination takes place. The interior of the flower is filled with bright yellow stamen and the exterior may be white, rose-red or yellow. The base of the flower is covered in fine spines that are almost like hairs. The flowers arrive in March through May.

Pollination and Fruit

• Over three-fourths of the pollination of the flowers is by nocturnal creatures. Bats sip at the nectar as do moths and other evening insects. In the course of their dinner the organisms collect and distribute pollen. When the flower is pollinated it will shrivel and lose its petals. The ovary at the center swells as it develops into a fruit. The fruit is 1 to 34 inches across and a rosy red. The interior is fleshy and juicy and when mature the fruit often splits.

Cultivation and Use

• The American Horticultural Society places Stenocereus in heat zones 12 to 10. A zone 12 receives more than 210 heat days or days over 86 degrees Fahrenheit. The cactus must be grown in very arid and hot areas. It is tolerant of drought and does equally well in sand or loam. Stenocereus needs very little irrigation once established and may be mulched with rock or gravel to prevent weeds. The cactus would make an attractive addition to a rock garden or as a container plant.