White Cactus Dahlias are stunning, spiky flowers grown from tuberous roots. They produce massive 8 to 10-inch pristine white blooms with petals that curl backwards, creating a needle-like, sculptural appearance. They thrive in full sun and well-draining soil, typically blooming from mid-summer through the first frosts. [1, 2, 3, 4, 5]
How to Plant and Grow
- Planting Time & Depth: Plant the tubers (often mistakenly referred to as bulbs) in spring once the danger of frost has passed. Dig a 6 to 8-inch hole, and lay the tuber flat with the growing points (“eyes”) facing up. Cover with 2 to 3 inches of soil. [1, 2, 3, 4, 5]
- Watering: Do not water immediately after planting to avoid root rot. Once the green sprouts appear above the soil, water deeply every few days. [1, 2]
- Sunlight: They require full sun (6-8 hours a day) to grow strong stems and promote heavy blooming. [1, 2, 3, 4, 5]
- Support: Because the blossoms are so large and heavy, most tall varieties require staking to prevent them from drooping or breaking in the wind. [1, 2, 3]
Popular White Cactus Varieties
- Dahlia ‘My Love’: Produces elegant, semi-cactus white blooms with gently curled petals, reaching 36 to 48 inches in height.
- Dahlia ‘Kenora Challenger’: Features large, pure white, show-stopping blooms.
- Trelyn Kiwi: A slightly shorter variety that starts with white petals, gradually flushing with pale pink as they mature. [1, 2]
