Carnegiea gigantea
Light: Full sun. Newly transplanted specimens may need temporary shade; preserve their original compass orientation to reduce sunburn.
Water: Very low water once established; established plants often thrive on Phoenix rainfall alone. During prolonged hot, dry weather, water deeply but infrequently, allowing soil to dry completely. Newly planted specimens need a transplant-specific watering plan; avoid watering immediately after planting if roots were damaged.
Soil: Excellent drainage is essential; use native gravelly or sandy desert soil. Avoid amended planting pockets, low spots, and locations receiving lawn irrigation.
Mature size: Typically 30–50 feet tall and 10–25 feet wide with arms; exceptional plants grow taller. Reaching full size takes many decades.
Bloom: White flowers appear mainly May–June in Phoenix. Flowering generally begins around 35–50 years of age, depending on growing conditions.
Evergreen / deciduous: Evergreen; green stems photosynthesize, with no persistent foliage.
Growth rate: Very slow, especially when young; established larger plants may grow several inches annually, depending on moisture and conditions.