Wednesday, 28 September 2011

Giant Hogweed and Parsnips - Burning Issues

Last year I noticed a particularly large fellow growing in our garden.

I didn't know him, nor where he had come from, and he became known as "that big bugger round the back".

We ignored him.

This year I was heard to exclaim "That big bugger round the back has brought his mates round!"

I have only recently learned his name - Heracleum Mantegazzianum or Giant Hogweed as he is less than affectionately known.

Unfortunately, with that knowledge comes other, more alarming knowledge.

It is not the fact that he is poisonous that alarms me.
We have plenty of poisonous plants, including Daphne who we introduced you to earlier this year.
And I am quietly impressed that he has chosen Daphne, Foxglove and Lily of the Valley as his 'bed mates'.

What does alarm me is that it is an offence under the Wildlife and Countryside Act 1981 to plant or cause Giant Hogweed to grow in the wild.

The Giant Hogweed is an escapee from the gardens of our Victorian Forefathers.
It's a familiar tale.
This particular plant is now a problem along our riverbanks and on derelict land. For some reason it can also be found in large numbers in Edinburgh City Centre.

The Giant Hogweed contains furocourmarins which can be released simply by brushing past the leaves. They affect the cell structure of your skin, making it more sensitive to the UV radiation in sunlight. This is known as photodermatitis.
It can cause severe burns, with long lasting scar tissue, and once your skin cells have been damaged it can take several years to rebuild your natural protection from UV radiation.
Casualties include people strimming the leaves in blissful ignorance,  and children using the stems as blowpipes.

Not a nice fellow, although he is quite splendid when in flower.
He is the tallest herbacious plant growing in Britain.
You can download an ID Sheet from here.

We are not required by law to destroy our "big bugger" and, whilst he and his mates have now seeded, the seeds do not fall far from the plant and we are unlikely to tramp them around on the soles of our shoes.

However, each plant can produce up to 50,000 seeds and they remain viable for up to 7 years. We shall have to be vigilant this coming year. Seedlings will have to be throttled and should we miss any, plants will need to be uprooted. At the very least, any flower heads will need to be removed before they set seed.

Scary stuff, eh?

Which brings me to the humble Parsnip.
He's a scary fellow too.
He also contains furocourmarins in his leaves.

It worries me that more is known about the furocourmarins in the Giant Hogweed than is known about the same chemical in a vegetable that is grown by gardeners across the land.

We do not know how concentrated the chemical is in Parsnips, nor whether the concentration varies at different stages of the Parsnip's life cycle.
We do know that handling the leaves may cause mild to moderate irritation. There have been reports of severe blistering and burning, although these appear to be few and far between.
I'm left dissatisfied with the information I can find.

All I can say, with a straight face, is

wear gloves when you're pulling your parsnips!


  1. Had to share this with you all:
    Genesis, no less!

  2. Take a look at Damo's blog
    Scroll down and you'll see what a parsnip burn is like, I'll always make sure I wear gloves when pulling parsnips from now on.

  3. It isn't just hogweed and parsnips. I did a quick search and turned up this snippet:

    "Members of the plant families Umbelliferae, Leguminosae, Apiaceae, Rutaceae, Moraceae, Rosaceae, Asteraceae, Brassicaceae, Clusiaceae, Convolvulaceae, Anacardiaceae, Fabaceae, and Ranunculaceae are noted to cause a phytophotodermatitis reaction. Common plants implicated in these families include celery, giant hogweed, angelica, parsnip, fennel, dill, anise, parsley, lime, lemon, rue, fig, mustard, scurf pea, and chrysanthemums"


    I was going to say that I haven't got hogweed or parsnips but it looks like I should keep quiet as I have several of the other potential offenders!

  4. That Hogweed sounds nasty, symptoms more associated with the tropics than the UK!

    We have a huge problem here with Himalayan Balsalm, it just spreads further and further each year down the river.
    It smells like burnt plastic when it's in flower and is a real nuisance, thankfully not because it's poisonous but because it kills off all other plant life as it grows and takes over.

    Take care with your Hogweed...I don't want to see any gruesome pictures of your escapades with its removal!

  5. I think a lot of people would be more than a little alarmed if they knew just how many 'ordinary' garden plants have a darker side.

    Interesting website here, chap used to work at The Poison Garden at Alnwick:

    or Alnwick itself:

  6. PS: In "And No Birds Sing", the first episode of Rosemary & Thyme (Felicity Kendal and Pam Ferris), nasty wife is systematically poisoning husband with Giant Hogweed in order to kill him off and marry her lover, who, conveniently, is the hubby's Doctor.

  7. Yeah, Jo, I remember seeing that now. I had forgotten that he had been burned. Thanks for the link for our readers though :)

  8. Thanks Wulf! I think! We have a fair few of those too.... now I have to go and find out what a scurf pea is...

  9. Kay, I cannot imagine any plant smelling of burnt plastic, yeuch! I wonder if that is an escapee too? And you guessed right, if I do get burnt I shall share all the gory details ;)

  10. That is very true, Bilbowaggins. Thanks for the links. I do use the first one and the garden at Alnwick has long been on my list of places to visit :)
    I love your PS! What a great little nugget of information :)


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