Update: see MM video Conservation Grazing part 2 Simon Berry/DWT mentions grazing and dropwort at around time point 1.10.00
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Good question, Claire. I've looked online and can't find any further advice re Dropwort which is extraordinary considering both how common and how poisonous it is.
I remember when I was helping with communal ground, the reported advice from the local council officers was - don't you deal with the dropwort, it's too dangerous, leave it to us - so perhaps, Claire, your local environmental council officers would advise you about dug up roots.
I've only strimmed my own dropwort so far, not had time to pull any roots out. Strimming seems to knock it back hard for the year. But dug up dock roots and thistle seedheads are a similar issue. I've asked elsewhere here what people do with these when there is a large volume. I guess that being a marginal plant, the dropwort roots have tannins like docks to withstand rotting, so no good dunking in a little water for a long time and hoping they'll rot (but see suggestion below). If you have a bonfire going anyway, stick them on that, or perhaps as I have heard gardening advice for bindweed - stick it inside a black rubble bag and leave to rot down for a couple of years until mushy but then I suppose you still have poisonous mush, or bag up and black bin it. (My council says do the last with docks.)
Guernsey advice re noxious weeds inc hwd - cut repeatedly, then burn or bag up.
https://www.gov.gg/CHttpHandler.ashx?id ... n%20plants. Says animals are particularly attracted to dug out roots. Says children at risk, touch it, then put fingers into mouths.
Lots of professional forum members here - can any of you help please?
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PS actually tried to pull up the roots - surprisingly easy if you wiggle it as the video says, where the roots are directly in damp ground, but not possible where the plant sits on dry ground with its roots further down towards a stream. What to do with the roots? As I was in a deep stream gully where no grazing animals can possibly come, I did what I do with nettle roots and hung the stems and roots on a tree branch or fence to dry out and die. (And no, I don't do this with dog poo bags! - saw a notice on a Nat. Trust meadow recently, saying they ought to, but can't, sell their meadow hay because visitors leave dog poo and dog poo bags all over the meadow..)
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PPS
https://www.theguardian.com/uk-news/202 ... rt-parsnip A slightly excitable article with good pictures of the roots and flower head.
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And a further thought - if you don't want to burn dropwort roots, you could try drowning them in deep water. I did this with a huge volume of dock roots. I threw the docks in because I didn't want to burn or black bin them and my reasoning was that I've never seen docks growing in deep water. I don't know whether it would work with dropwort, which is a marginal but not, as far as I know a deep water plant, but I think it might be worth a try or at least some further investigation (perhaps I'll try drowning some in an old dustbin this year.) I have a newish pond about 3-4' deep in places. Rather alarmingly, the docks rooted and grew on the earth pond floor for a few weeks, but then they died. Granted they will have enriched it, but probably only marginally, and there is water running through to keep it fresh.