Medium to tall, hairless, erect, often bluish green plant to 1.5 metres. Leaves opposite, linear to oblong, untoothed and unstalked. Bracts oval-triangular, pointed, bright green. Umbels with 2 to 6 main rays, capsule 13 to 17 mm smooth.

Disturbed ground and waste places, gardens.

June and July.

Biennial.

Casual or established throughout Britain as far north as southern Scotland scarce in Wales.

Local and probably increasing in Leicestershire and Rutland. In the Flora of Leicestershire (Primavesi and Evans 1988) it was found in 4 of the 617 tetrads.

In the current checklist (Jeeves, 2011) it is listed as Alien (archaeophyte); scarce

It was on the 2011 VC55 Rare Plant Register (Jeeves, 2011) but was under-recorded. It is found in more sites than previously known, and does not meet the criteria for the current RPR (Hall and Woodward, 2022)