Euphorbia mammillaris f. variegata
Common Name: variegated corn cob
Geographic Origin: Euphorbia mammillaris f. variegata is a nursery-created forma of E. mammillaris, which originates from the subtropical thorny bush-lands, steppe, and low-savanna within Little Karoo and the Southern Cape of South Africa.
Description: The variegated corn cob is a succulent shrublet that forms a dense cluster of club-shaped lateral branches. The thick stems are simple, ribbed, and covered in vertical rows of hexagonal tubercules, resembling an ear of corn. Although the straight species possesses dark green stems, the stem of the variegated forma will be cream-colored to greenish-white, with random sections of emerald green. Small, ephemeral leaves may be present on the extending tubercules, but the spines are scattered and do not emerge from the tubercules. Thick, blunt, and white, the extending spines are solitary sterile peduncles.
From late winter to early summer, succulents will develop a solitary yellow cyathia at the apex of each stem, possessing several bracts and yellow-green to purple nectar glands. Flowers will be followed by the obtusely lobed fruits and smooth ovoid seeds.
- Watering: Moderate
- Lighting: Requires full sun, but is capable of surviving moderate shade. However, plants grown under shady conditions must be slowly hardened off before placing in full sun, to avoid severe scorching.
- Propagation: The variegated corn cob may be propagated through offsets, cuttings, or seed. However, offsets are only rarely produced after several years, and seed may be difficult to find or germinate. As a result, the species is usually propagated by cuttings, which should be dipped in rooting hormone to ensure success.
- Cold tolerance: 20°F, USDA hardiness zones 9a to 11b.
- Special Accommodations: E. mammillaris f. variegata is very frost tender and should only be planted in frost-free locations. If grown in poor soil or outdoors, feed monthly with a half-strength cacti or succulent fertilizer. However, in summer, a high potassium fertilizer is required to ensure growth. When adequate heat, sun, water, and nutrients are provided, the species will show remarkable growth during the active growing season.