Biennial or perennial herb mostly 0.5-1.5 m tall, hairy. Basal leaves ovate to lanceolate, long-stalked. Flower clusters extended, occasionally branched. Calyx lobes ovate to elliptic. Corolla 4-5.5 cm long, purple to pink or white, usually spotted inside. Fruit capsule ovoid.
This is the popular Foxglove of cottage gardens and perennial borders, a variable, lime-loving species. It is available in a range of cultivars and hybrid groups, notable among which are: 'Alba', flowers white; Excelsior Hybrid Group, which grow to 2 m tall with flowers in pastel shades; and Foxy Hybrid Group, which grow to 75 cm with flowers carmine, pink, cream, and white spotted with maroon.
subsp. heywoodii P.& M. Silva is occasionally offered; the whole plant is densely whitepubescent and the flowers are white, sometimes with a hint of yellow or pink.
D. ×mertonensis Buxton & C. Darl. is a hybrid, D. grandiflora × D. purpurea, growing to over 0.5 m tall with large pinkish flowers to about 5 cm long.
Source: (2002). Scrophulariaceae. In: . Horticultural Flora of South-eastern Australia. Volume 4. Flowering plants. Dicotyledons. Part 3. The identification of garden and cultivated plants. University of New South Wales Press.