An annual or short-lived perennial growing to a maximum of 2.5 metres (8.2 ft), it has erect purplish stems and rounded umbels of minuscule white or pale pink flowers in late summer.

[4] However it tolerates a range of conditions including fields, hedgerows, open woods, marshes and fens.

It has recently been determined to be an invasive weed in New Brunswick and Cape Breton, Nova Scotia, Canada.

The cultivar 'Ebony', with pink flowers, has gained the Royal Horticultural Society's Award of Garden Merit.

The stem was eaten fresh, and the leaves could be boiled to a stew for storage or cooked with milk.