A darker shade of inky blue for autumn colour

ACONITUMS or monkshood are mostly of deep blue colour, indigo and violet, although there are some paler blue kinds too and some have pale yellow flowers. Most of those seen in flower borders are deep-blue in colour, especially at this time of year. The inky blue of monkshood makes a great contrast with late summer and autumn flowers, many of which are yellow, such as rudbeckia, helianthus, coreopsis and helenium.

Contrasting blue with these colours can give added richness to a border combination. Just a few clumps of aconitum dotted through a bed or border can be very effective. The plant sends up tall flowering stems from a basal clump of leaves.

The flowers are carried at the tops of the stems and on branches lower down. The topmost flowers open first and are followed by the flowers on the side-stems. When the first flowers have gone over, they can be snipped off to encourage the production of late flowers.

The flowering period is mid-summer onwards, well into autumn, with some kinds flowering earlier and some later. The lovely variety ‘Bicolor’ has blue and white flowers fading together. ‘Newry Blue’ has medium blue flowers, not as deep as others, and it flowers from mid- to late summer. ‘Sparks Variety’ is a really deep brooding violet, flowering to late summer. ‘Stainless Steel’ is grey blue, a real beauty.

‘Arendsii’ is deep blue and late-flowering, often well into October, and is a most valuable plant for its late-season, contrasting blue colour. Aconitum is a very good cut flower and by cutting some for use indoors, the garden can benefit from an extended display.

Wolf ’s bane is yellow-flowered, a different species, quite a pale yellow, with much smaller flowers than the usual kinds, almost tubular in shape, flowering in late summer.

Aconitum is part of the buttercup family, and many members of this family like slightly heavy soil, moisture-retentive, but not wet, as does monkshood. If it is grown in soil that is too light and well-drained, the plants tend to be stunted in growth with fewer flowers, but in very rich soil they can grow too tall with a tendency to blow over in a strong wind.

Aconitums grow quite well when shaded for part of the day but they flower better in open sunshine.

Plant now for flowers next year.