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14 messages
18/07/2013 at 14:21

Has anyone got any ideas how to manage this problem? This is the 3rd year that I have removed as much of the root as a spade slice at 45 deg will get to prevent seeding, however this is a chore. Colonisation by wild flowers is increasing and now have a healthy colony of Southern Marsh Orchids which precudes a chemical solution. I intend to cut the meadow in September as before. Hoping someone has the answer to this dilema.

18/07/2013 at 14:38

Am I right in thinking you can cut the stems and pour Roundup down inside the hollow stem? Or is that Japanese knotweed? 

18/07/2013 at 14:55

Sounds like a recipe for toxic overload as I have maybe 500 plants. Not a job I would fancy. Sure it would work

18/07/2013 at 15:25

Cover anything you don't want to harm with a flower-pot or bucket and use an agricultural formulation of Roundup.

It is a weed that will multiply if you cut the root.  You may have compounded your problem.

19/07/2013 at 08:39

I know it would be a real chore but could you use a contact weed killer rather than a spray  to make sure you only get the hogweed. Also cutting off the flower heads before they set seed wil help, if cutting the roots exacerbates this problem then doing this to prevent seeding may be the better option?

19/07/2013 at 17:37

Isn't giant hogweed a bi- or tri-annual? If you manage to get every plant every year so none of them ever produce a seed, it should be scarce four years from now. I think the seeds have been known to wait up to seven years and then sprout again, though, so you'd have to stay vigilant, and if you have a riverbank in that meadow it'll get seeds washed up from further upriver.

Some sprayers have an optional sponge attachment that you can use to wipe weedkiller on to leaves without spraying at all, but you'll get sap on the sponge, so don't touch it afterwards!

Actual eradication plan if you are on a river:

Get an army.

Start scouts at the tops of tributaries, each equipped with a map and a pen. Each scout follows one side of a watercourse downhill, marking on the map every hogweed found.

Copy all hogweed finds onto your master map at HQ, and mark them with the date.

Send out sprayer crews to the hogweeds furthest up each watercourse. Each crew needs a spotter to make sure they don't do something stupid, a sprayer to deliver the toxin and a chopper with a really long spear to lop off flower heads. Each crew marks as far down the river as they got before they ran out of ammo or the wind came up.

Repeat spraying on suitable days until your teams get downstream of you.

Repeat the whole process next year, and the year after that, and the year after that and so on for eight years. Starting in year nine, you can start your scout teams a little further downstream, because any watercourse where no plants have been found in 8 years can be declared clear.

Once the scouts are starting downstream of you, you can declare local victory, and then find out that someone's transported seeds or contaminated soil to a site upstream of you and the b*****d things are BACK.


So, ah, which river valley are we doing first?

20/07/2013 at 08:10

Sorry to say, Charlie November has a point!

We have the full works here hogweed, knotweed and himilayan primrose. Happy days.

On top of this we have about an acre of what we would like to be meadow if it were not for the braken. Our plan is to get a good mower and cut cut cut. As someone says above, after a couple of years you'll loose the existing plants but the seeds will still be germinating for up to seven. After that it will be straglers drifting in which should be more manageable & you can let your meadow develope.

Seems like a long time to wait I know.

Sundays job for me is to de-flower all the hogweed in hard to reach places which has come up this year to at least stop more seeds. Those in open areas have been mowed.

20/07/2013 at 10:02

Cut all the flowers off and remove.  

Get a knapsack sprayer fill with glyphosate/Roundup and spend an evening or two walking over every inch of your meadow spraying every individual hogweed plant - then leave well alone.  They'll be well and truly dead by the time you mow the meadow in September.  

You might have to do this every year for the next few years but it'll be worth it and it's the only way to do it.  If I did this over three grazing meadows a few years ago and it worked.

I was also digging out ragwort at the same time 

We had orchids, fritillaries and other precious things growing there - they weren't harmed. 

08/08/2013 at 18:12

Thanks everyone for the advixe, game on!

08/08/2014 at 06:37

I've just encountered Japanese Hogweed for the first time on a trip to West Sussex. The gardener of the place I was staying had been asked to remove it; he wore gloves but they got wet in the rain and by that evening his hands were covered in blisters. Three MONTHS later his hands were just recovering from being covered in black, oozing blisters and sores! Do NOT touch this stuff - have a look at the various articles on the internet. Here's a link to one:


08/08/2014 at 07:14

The Original Post was about the British Native Hogweed Heracleum sphondylium, a common weed of pastures and hedgerows. It is not dangerous except for people who have a specific allergy.  

As a child I gathered buckets and buckets full of it for pet rabbits - it's one of their favourite foods. 

08/08/2014 at 16:39

Aha - my mistake - with it just saying Hogweed, I assumed .......silly me 

08/08/2014 at 16:40

  British Native Hogweed is much more common than the alien Giant Hogweed. 

08/08/2014 at 16:42

and a right pain in the......... meadow.

Those enormous leaves swamp everything

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