Plant Primer: Golden barrel cactus

Golden barrel cactus

Light: full sun

Height: 3 to 4 feet

Spread: 2 to 3 feet

USDA Hardiness Zone: 9

Origin: Mexico

Golden barrel cactus (Echinocactus grusonii) is a good-looking and colorful plant. These cacti are perfectly round when young but elongate as they mature, taking on the barrel shape for which they are named.

The golden appearance comes from the yellow spines. Cactus spines are modified leaves that serve this plant in a variety of ways. First, the sharp spines protect the cacti-water-storing flesh from being eaten from thirsty desert predators (nobody wants a mouthful of sharp spines).

They also act as a sort of sunscreen from the desert sun; while one spine creates only a sliver of shade, hundreds of spines create more coverage.

Unlike other leaves, however, the spines are not where photosynthesis takes place. Instead, this happens through the blue-green surface of the golden barrel cactus. During the rainy season, the ribs will expand and hold water, reserving it for times of drought.

The golden barrel cactus reaches flowering maturity at about 20 years old, when small yellow flowers appear on the top, like a crown.

See the beauty of the golden barrel cactus in the Desert Biome at Franklin Park Conservatory and Botanical Gardens.

— Barbara Arnold

Franklin Park