Cylindropuntia fosbergii
mason valley cholla
Colorado Desert, southern California
Overview
Cylindropuntia fosbergii, the Mason Valley cholla, is a shrubby cactus of the Colorado Desert in southern California, forming a branched, upright plant 2-6 feet (0.6-1.8 m) tall. Its cylindrical stem segments are 2-6 inches (5-15 cm) long and about 0.6-1 inch (1.5-2.5 cm) thick, green to grey-green, and covered with raised tubercles. Each areole bears dense, spreading spines 0.4-1.2 inches (1-3 cm) long sheathed in papery straw-colored coverings that catch the light. Flowers open in spring at the stem tips, 1-1.5 inches (2.5-4 cm) across, in yellow to greenish-bronze tones, followed by dry, tan, spiny fruits. The barbed spines detach readily and cling to skin and clothing, which makes the plant hazardous to handle and limits its placement near paths. C. fosbergii grows on sandy and gravelly desert flats and bajadas, often among creosote bush scrub. It withstands intense heat and prolonged drought but is damaged by hard frost and by soils that hold winter moisture.
Native Range
Native to the Colorado Desert of southern California, in the Anza-Borrego region of San Diego and Imperial counties. It grows on sandy and gravelly desert flats, washes, and bajadas within creosote bush and cactus scrub.Suggested Uses
Used in desert and xeriscape gardens, cactus collections, and rock gardens in frost-free regions, where it forms a spiny barrier. It is placed well back from paths and seating because of the detachable spines. In colder areas it is grown in containers that can be sheltered over winter.How to Identify
Appearance
Size & Dimensions
Height2' - 6'
Width/Spread2' - 4'
Bloom Information
Flowering occurs in spring, generally April to May, with cup-shaped flowers 1-1.5 inches (2.5-4 cm) wide opening at the tips of the stem segments. Blooms range from yellow to greenish-bronze and last a few days each. Dry, tan, spiny fruits follow and persist on the plant into summer.
Detailed Descriptions
Flower Description
yellow to greenish-bronzeFoliage Description
green to grey-green stemsGrowing Conditions
Sun Requirements
Requires 8-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grow in full sun in sharply drained sandy or gravelly soil that mimics its desert origin. Water sparingly during the warm season and keep the plant dry through winter, as cold wet soil causes stem rot. It tolerates extreme heat and reflected warmth and needs no supplemental feeding in lean ground. Frost below the mid-20s Fahrenheit (around -4 C) damages the stems, so it is grown outdoors only in frost-free desert climates or kept in containers moved under cover. Propagation is simple from detached stem segments, which root where they fall. The barbed spines make routine maintenance slow, so generous spacing from walkways reduces contact.Pruning
No routine pruning is required. Overgrown or damaged segments are removed at the joint with long-handled tongs, since the spines and detachable segments cling to skin. Removed segments root readily, so they are discarded away from areas where new plants are unwanted.Container Growing
✓ Suitable for container growing
Minimum container size: 5 gallons