Friday, 27 March 2009


A plant which is appearing and coming into flower now, in late March, is the Butterbur (Petasites hybridus). Although it is fairly closely related to Coltsfoot (see my article dated 19th March 2009) it is an altogether stranger affair. There is something a bit fungoid about it and, indeed Geoffrey Grigson (1) reports that that an old Dorset name for it is ‘Early Mushroom’ – and it’s not hard to see why. It is particularly common on the river banks and some of the few (relatively) undisturbed areas that we have left.
Butterbur, like Holly (see my article dated 26th February 2009), is dioecious, that is male and female flowers occur on different plants. The squatter, pinker male plants tend to turn brown and shrivel once they have shed their pollen whilst the taller, more open female flower-spikes tend to elongate into ‘tassels’ once they have been fertilised and begin to bear seed. The top picture shows three male flower spikes whilst the bottom picture shows a group of female plants whose flowers have recently been fertilised. I have observed, over the years, that males and females tend to form separate colonies. A few years ago, near to the towpath of the Bridgewater Canal, there used to be a colony of male plants right next to a colony of female plants. I used to picture them as a group of nervous teenagers eyeing each other across a dance floor. Unfortunately, this site is now overgrown with brambles and the Butterbur is gone.
Once the business of reproduction is over, both sexes produce huge, rhubarb-like leaves (which I will discuss in a later article).
It is a curious fact that while Butterbur is quite common in many parts of the UK, female plants tend to be less so. As Professor Clive Stace (2) puts it: “male plant frequent throughout most of [the] B[ritish] I[sles]; female plant frequent in N[orth] & C[entral] E[ngland], very sporadic elsewhere.”
Fifty years ago, in a classic book on British wild flowers (3), John Gilmour and Max Walters discussed this distribution; they wrote:
“Professor Valentine has shown ... that the male plant of this species occurs quite commonly throughout the British Isles, but the female plant has a curiously restricted distribution, chiefly in the north-west of England – it is, for example, quite common around Manchester. Within this main area the female plants apparently produce abundant seed which in tests has germinated freely to give both male and female plants in the progeny. Valentine suggests that the restriction of the female must be due to some climatic factor which does not operate in the same way on the more adaptable males. He also suggests that some of the wide distribution of the male plant may be due to its having been planted to provide early nectar for bees.”
I am not aware of any more recent work on this question – but that doesn’t mean that it hasn’t been carried out (any information gratefully received).
Nevertheless, Butterbur is not only a curious and interesting plant but it is also, as the above passage suggests, of great local significance. It is a very characteristic of the Mersey Valley and is, I would also suggest, a key element of our local biodiversity.

Dave Bishop, March 2009

1. ‘The Englishman’s Flora’ by Geoffrey Grigson, Paladin 1975 (first pub. 1958)

2. ‘New Flora of the British Isles’ by Clive Stace, Cambridge University Press, 1991

3. ‘Wild Flowers’ by John Gilmour and Max Walters, Collins, 1959

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