Sunday, April 18, 2010

Insect Fuelling Station

Butterbur is in full flower all along the banks of the river Wear, where its creeping rhizomes thrive in silty soil left by winter floods. They're often buried to a considerable depth by silt after floods but the starch food reserves in the rhizomes provide the energy needed for early growth before the flowers and leaves force their way up into the light, in much the same way that colt'sfoot's rhizome food reserves allow it to tolerate burial. Butterbur is a plant that seems to be sensitive to winter climate because after very mild winters - of the kind we experienced for a decade before the most recent - it will often begin to produce leaves at the same time as flowers, but after severe winters, like the last, it reverts to its normal behaviour and delays producing any leaves until flowering is well underway. When they finally expand the leaves are spectacularly large, but before that happens the flowers are an excellent food source for insects in spring....
.... when bees visit for pollen and nectar....
.... and the nectar is an irresistible lure of newly-emerged peacock butterflies.
Butterbur exists as separate male and female plants, with their creeping rhizomes forming very large clonal, single gender patches. In some parts of England only male clones are present but here in the North East we have both sexes. The plants at the top of this post are males but the females (immediately above) are easy to spot because once they've been pollinated their stems elongate very rapidly and within a week or two they begin to produce large numbers of tiny plumed seeds. They do seem to expand their leaves more readily than the males, presumably because of the need to supply sugars to the developing seeds once the bees and butterflies have done their work.

13 comments:

  1. Hi again, Phil: Many thanks for your comment/identification of the Hazel catkin. This item on the butterbur is very interesting to me. I have always liked the butterbur and was intrigued, when a child, to learn that the large leaves were used in earlier times to wrap up butter to help keep it fresh, hence at least one source of the plant's name. I'll pop down to Kirkwhelpington again to see if I can find any females.

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  2. An impressive and valuable plant. I don't think I've seen it on the IoW.

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  3. I was going to do a similar post (but not as factual or scientific and not with the photographic quality you produce) as I have been looking at a couple of sites in Northumberland where female flowers are and one of them is only a few miles from here but it will be next week before I'm off work again. Fascinating post Phil.

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  4. Thanks Nigel, they really are impressive flowers. Sometimes, when the river scours away the silt, the network of rhizomes is exposed and they're amazingly tough - I suspect that play quite an important role in stabilising riverbanks

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  5. Hi Emma, I made the mistake of introducing its close relative winter heliotrope Petasites fragrans into my garden - it has a distinctive marzipan smell but it's spreading like a triffid..

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  6. Hi Rob., there are some fine displays of it at the moment along the riverbank below the cathedral in Durham...

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  7. Fascinating post Phil, and excellent pictures.
    I came across this a few days ago, just coming into flower. Masses of it. Impressive to see.

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  8. Hi Keith, while I was photographing it I noticed that the heads of some of the bees were almost white with a dense layer of pollen - it must be a very good food source for them...

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  9. Hello Phil. Just the other day I took daughter and a couple of her friends to a nice park at Langley Moor. We had a walk along the riverside and there were many large groups of Butterbur. I was pleased to see how many insects and butterflies were visiting them. As your title says, they really are a fuelling station for the insects.

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  10. I saw a patch on thursday at a churchard at Castle Eden churchyard clustered in a particular sunken corner of the graveyard, probably more water-logged on than the rest of the graveyard. Probably best not to dwell on where it's getting all its nutrients from!

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  11. Hi Dougie, A grim thought! I seem to remember reading somewhere that its rhizomes were used for treating the Black Death(unsuccessfully). I noticed some coming into flower around the river bank in Durham on Friday.

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  12. Hi Phil, I'm starting to see this everywhere! Walking along the Sands this morning I came across a chunky cluster next to a large Willow tree next to the Wear. I walked up and down either side trying to figure out whether there was perhaps some local feature or condition that would favour its development as it seemed to be concentrated in that one area. It's absent upstream and downstream from this one spot so it's curious that it should favour this one area round the willow tree. I suspect I'm just over-analysing and it's just being fickle!

    http://www.flickr.com/photos/djnisbet/sets/72157626408034448/

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  13. Hi Dougie,I think it forms big clonal patches - there's a very stout underground branching rhizome. I wonder how it becomes established in the first place - seeds would need to be somewhere where they wouldn't become washed away before they can establish. Bits of rhizome broken off during floods must spread it too, I guess...

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