Heracleum branca-ursina

As we head into peak hogweed season I'm reminded that I never got round to posting these photos from last year. Bear's Breech Hogweed (Heracleum branca-ursina) is one of those Sell and Murrell taxa that is not fully resolved and merits further investigation. Seen as a colony it is striking and distinctive, typically well over 1.5m tall rather than the more usually waist high Hogweed (Heracleum sphondylium). The outer flowers (and seeds later) are also very large.

This all said, the two species do seem to overlap and I would be very cautious about recording the former based on flower size alone. Its not unusual to find perfectly normal Hogweed with flowers larger than stated in the Sell & Murrell key. In my view and based on relatively few encounters it is probably more defensible as a variety of Hogweed, rather than a distinct species or subspecies. I don't think there are any significant barriers to inter-breeding. One of my first encounters with this plant was at Sun Lane Nature Reserve (VC64) where there was a nice stand, and then plants with and grading towards Hogweed with increasing distance from the main stand.

The other big question is where it comes from. It seems to be an introduction, and a relatively short-lived one at that in the few locations where I have known it in the past.

Below is a selection of photographs taken last June in a sunny glade in plantation woodland at Temple Newsam (VC64).

Heracleum sphondylium inflorescence (left) and branca-ursina (right)

Heracleum branca-ursina with 2 pence coin for scale

Colony of plants 2m or more tall (I'm 5' 7'' and these towered above me)

Typical foliage which has quite a distinctive jizz, in terms of shape, size and texture. Hard to put into words and best understood firsthand