Dahlia 'Black Diamond' (Ba) — Bushy, clump-forming, tuberous perennial

Overview

Dahlia 'Black Diamond' (Ba) is a bushy, clump-forming, tuberous perennial bedding in the genus Dahlia, part of the Asteraceae family, with green, occasionally dark-leaved foliage. Dahlia 'Black Diamond' (Ba) grows best in full sun, and tolerates loam soils and neutral pH. Its UK hardiness is rated H4. Suggested uses include borders, containers and cut flowers.

About

Dahlia 'Black Diamond' is a clump-forming, tuberous perennial in the Asteraceae grown as bedding and for cut flowers. It produces stems and blooms across the summer into autumn, flowering July to October. The foliage is generally green, sometimes showing darker leaves. Plant in a south-facing, sheltered spot in loam kept moist but well drained.

About the genus

Dahlias come from the high meadows of Mexico, and somewhere in that heritage is the explanation for how they behave here: tender to frost, hungry, generous beyond all reason. No other plant gives you quite so much for so little. One tuber, planted after the last frost, becomes a shrub's worth of flowers by August — and the more you cut, the more they come.The range is faintly ridiculous. Tight pompoms, spiky cactus types, singles the bees adore, dinner-plates the size of your face. Whatever your garden's mood, there is a dahlia that agrees with it, which is probably why every generation falls out of love with them and then, a decade later, falls straight back in.They're at their best when much of the garden is winding down — late summer into autumn, flowering hard until the first frost calls time. I think of them as the encore. And they always play it.

Written by Henry

In the garden

Dahlia 'Black Diamond' belongs to the genus Dahlia within the Asteraceae and, like its relatives, arises from swollen tubers that resprout each season; the genus originates in Mexico and Central America. As a bedding and herbaceous perennial it is commonly used where summer-to-autumn colour and cut stems are required. Flowering occurs from July to October. Give it a sunny, south-facing position with some shelter from strong winds. It prefers loam of neutral pH and soil that retains moisture without waterlogging; heavy clay or very dry soils will restrict performance. The plant is rated H4 (average hardiness), so choose a protected site in colder districts or provide winter protection where late severe frosts are possible. Treat it as a tuberous perennial: plant in free-draining, enriched soil, keep moisture consistent during the growing season and locate where flowers can be cut for vases. Dahlia 'Black Diamond' works well in borders and containers where a succession of cut stems is needed, and its tuberous habit means the same clump can supply stems repeatedly through the July to October period.