Overview

Dahlia 'Black Diamond' 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' 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 cultivar of the Dahlia genus, which comprises perennial plants with tuberous roots and finely dissected leaves, known for their prominent flowerheads. This bushy, clump-forming herbaceous perennial thrives in full sun on south-facing, sheltered sites with moist but well-drained loam soil of neutral pH. It is hardy to UK zone H4 and is suitable for borders, containers, and as cut flowers. Cultivation involves growing in fertile, humus-rich soil, pinching out growing tips to promote bushiness, and staking if necessary. Tubers should be lifted and stored frost-free in colder areas after the first frost.

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.

Growing conditions

Best soil and position for Dahlia

Sunlight
Full sun
Soil type
Loam
Soil pH
Neutral
Soil moisture
Moist but well-drained
Aspect
South-facing
Exposure
Sheltered
UK hardiness
H4

Plant details

Dahlia 'Black Diamond' size, habit and characteristics

Plant type
Bedding, Herbaceous Perennial
Habit
Bushy, clump-forming, tuberous perennial
Foliage
Green, occasionally dark-leaved
Suggested uses
Borders, containers, cut flowers

Care notes

Pruning and caring for Dahlia 'Black Diamond'

Propagation
Division, cuttings, seed
Pest resistance
Generally pest-resistant
Disease resistance
Generally disease-resistant

Frequently asked questions

Where is the best place to plant Dahlia 'Black Diamond'?

Dahlia 'Black Diamond' prefers full sun. It suits sheltered positions.

What soil does Dahlia 'Black Diamond' need?

Dahlia 'Black Diamond' grows best in loam soil. It prefers neutral soil. Aim for soil that stays moist but well-drained.

Is Dahlia 'Black Diamond' hardy in the UK?

Dahlia 'Black Diamond' has an RHS hardiness rating of H4, meaning it is hardy through an average UK winter, tolerating -10 to -5°C.

How do I propagate Dahlia 'Black Diamond'?

Division, cuttings, seed.

More in the Dahlia genus

Browse all Dahlia