Dahlia 'Black Jack' (Cactus)

Dahlia ‘Black Jack’ is a dramatic cactus variety that commands attention with its spiky, dark maroon petals that appear almost black in certain lights. It adds instant depth and mystery to the garden, serving as a perfect counterpoint to brighter, lighter blooms in a mixed herbaceous border.

This variety forms a bushy, upright plant with dark, lush foliage that enhances the moody intensity of the flowers. The pointed, tubular petals radiate outward, giving the blooms a star-like quality that adds texture and architectural interest to planting schemes.

Plant in full sun to help the dark pigments develop fully, ensuring the soil is rich in organic matter and well-drained. Like all dahlias, it appreciates a feeding of high-potash fertiliser once blooming begins to sustain its performance.

Support with stakes as the plant grows, as the stems can become top-heavy with flowers. Remove spent blooms to keep the plant tidy and productive, and lift tubers in autumn to protect them from freezing temperatures.

A brilliant choice for contemporary and gothic-inspired gardens, ‘Black Jack’ looks stunning when planted alongside lime-green foliage or bright orange flowers, creating a bold, high-contrast display.