controlling hogweed
 

I mean regular hogweed, not the giant variety thank goodness.

Over the last 20 years (there was none at all then) it has installed
itself in the fields and likes to come up in cleared areas around trees
and shrubs. I've not had much luck with glyphosate, the huge root seems
to laugh it off. I've tried cutting the flower heads off, on the theory
that since it's biennial (I think) it will go away, but the seeds seem to
set anyway.

Yesterday I dug a bunch of it up as best as possible, but of course there
was a lot of root left in ground. Is it likely to come back, or is this
a good method.

Lots of info on the giant variety but not so much on regular hogweed; it
has the same chemical that causes sunlight activated burns, just not so
much of it, and the flowering stems can get to about 6 ft.

Thanks for any tips,

-E



--
Gardening in Lower Normandy

controlling hogweed
 

On 28/05/2014 11:15, Emery Davis wrote:
I mean regular hogweed, not the giant variety thank goodness.

Over the last 20 years (there was none at all then) it has installed
itself in the fields and likes to come up in cleared areas around trees
and shrubs. I've not had much luck with glyphosate, the huge root seems
to laugh it off. I've tried cutting the flower heads off, on the theory
that since it's biennial (I think) it will go away, but the seeds seem to
set anyway.

Yesterday I dug a bunch of it up as best as possible, but of course there
was a lot of root left in ground. Is it likely to come back, or is this
a good method.

It should be good enough to hit it with any broadleaf specific herbicide
assuming it is in grass or glyphosate if you don't mind a bit of
collateral damage and scythe it down in flower before it sets seed.

--
Regards,
Martin Brown

controlling hogweed
 

On Wed, 28 May 2014 11:27:10 +0100, Martin Brown wrote:

On 28/05/2014 11:15, Emery Davis wrote:
I mean regular hogweed, not the giant variety thank goodness.

[]

It should be good enough to hit it with any broadleaf specific herbicide
assuming it is in grass or glyphosate if you don't mind a bit of
collateral damage and scythe it down in flower before it sets seed.

I haven't found glyphosate to be effective, possibly I've been a little
late in the season. Do you have a particular boradleaf herbicide to
recommend? (If it kills dock and too, that would be just fine...)

Thanks,

-E

--
Gardening in Lower Normandy

controlling hogweed
 

In article ,
Emery Davis wrote:
On Wed, 28 May 2014 11:27:10 +0100, Martin Brown wrote:

I mean regular hogweed, not the giant variety thank goodness.

That's not a major problem, despite the tabloid hysteria. Yes, it's
a thug.

It should be good enough to hit it with any broadleaf specific herbicide
assuming it is in grass or glyphosate if you don't mind a bit of
collateral damage and scythe it down in flower before it sets seed.

I haven't found glyphosate to be effective, possibly I've been a little
late in the season. Do you have a particular boradleaf herbicide to
recommend? (If it kills dock and too, that would be just fine...)

The normal problem with using glyphosate is following the instructions
on the bottle :-(

It works better if you use it at HALF strength, and possibly repeat
it a few weeks later (in cool weather). And, yes, start as soon as
there is enough foliage.

Glyphosate is actually grass-specific, and will kill grass at levels
that leave most other plants alive. The only one more effective that
I know of is brushwood killer - but even that doesn't kill established
trees and shrubs in one go.


Regards,
Nick Maclaren.

controlling hogweed
 

On 28/05/2014 12:46, Nick Maclaren wrote:
In article ,
Emery Davis wrote:
On Wed, 28 May 2014 11:27:10 +0100, Martin Brown wrote:

I mean regular hogweed, not the giant variety thank goodness.

That's not a major problem, despite the tabloid hysteria. Yes, it's
a thug.

It should be good enough to hit it with any broadleaf specific herbicide
assuming it is in grass or glyphosate if you don't mind a bit of
collateral damage and scythe it down in flower before it sets seed.

I haven't found glyphosate to be effective, possibly I've been a little
late in the season. Do you have a particular boradleaf herbicide to
recommend? (If it kills dock and too, that would be just fine...)

The normal problem with using glyphosate is following the instructions
on the bottle :-(

I agree, but it is in the manufacturers best interests for people to use
more of the concentrate than is needed for optimum kill. You have to
wait a bit longer for the weeds to die but it gives the glyphosate more
time to translocate around the root system on pernicious weeds.

They sell a fast acting prediluted "Roundup" that contains something
else that kills the weeds before the glyphosate has time to act! Selling
impure water has very high profit margin (windscreen wash too).

It works better if you use it at HALF strength, and possibly repeat
it a few weeks later (in cool weather). And, yes, start as soon as
there is enough foliage.

Absolutely agree - slower but a more complete kill that goes deeper.

Actually persecuting any pernicious weed with whatever means you happen
to be using at the time is not a bad strategy. You don't have to leave
it for long growing unmolested with good leaves in the sun to lose control.

I find a combination of chemical attack followed by either scorched
earth or physically digging it out the most effective method. YMMV

It is easier to spot any green regrowth or weed seedlings against a
charred black background.

Glyphosate is actually grass-specific, and will kill grass at levels
that leave most other plants alive. The only one more effective that
I know of is brushwood killer - but even that doesn't kill established
trees and shrubs in one go.

The one thing apart from waxy plants I find it ineffective against is
buttercup. I have killed some larger areas with glyphosate and always
noticed that afterwards the buttercup is quickly back in business.

--
Regards,
Martin Brown

controlling hogweed
 

In article ,
Martin Brown wrote:

Glyphosate is actually grass-specific, and will kill grass at levels
that leave most other plants alive. The only one more effective that
I know of is brushwood killer - but even that doesn't kill established
trees and shrubs in one go.

The one thing apart from waxy plants I find it ineffective against is
buttercup. I have killed some larger areas with glyphosate and always
noticed that afterwards the buttercup is quickly back in business.

It has never killed regrowth from stumps for me, and kills field
bindweed only after several years' use. I have heard that horsetail
is also essentially immortal.


Regards,
Nick Maclaren.

controlling hogweed
 

On Wed, 28 May 2014 13:07:05 +0100, Martin Brown wrote:

On 28/05/2014 12:46, Nick Maclaren wrote:
In article ,
Emery Davis wrote:
On Wed, 28 May 2014 11:27:10 +0100, Martin Brown wrote:

I mean regular hogweed, not the giant variety thank goodness.

That's not a major problem, despite the tabloid hysteria. Yes, it's a
thug.

It's pretty invasive. There's now enough of it in the area that it will
probably be impossible to eliminate entirely.


It should be good enough to hit it with any broadleaf specific
herbicide assuming it is in grass or glyphosate if you don't mind a
bit of collateral damage and scythe it down in flower before it sets
seed.

I haven't found glyphosate to be effective, possibly I've been a
little late in the season. Do you have a particular boradleaf
herbicide to recommend? (If it kills dock and too, that would be just
fine...)

The normal problem with using glyphosate is following the instructions
on the bottle :-(

I agree, but it is in the manufacturers best interests for people to use
more of the concentrate than is needed for optimum kill. You have to
wait a bit longer for the weeds to die but it gives the glyphosate more
time to translocate around the root system on pernicious weeds.


I know how to use it. But the weather is not always propitious, and I'm
not always here. So sometimes it is catch as catch can.

They sell a fast acting prediluted "Roundup" that contains something
else that kills the weeds before the glyphosate has time to act! Selling
impure water has very high profit margin (windscreen wash too).

True. ;) I buy it from the ag coop. There may be a cheaper place but
not so much so that it's worth putting the time in to find.

[]
It is easier to spot any green regrowth or weed seedlings against a
charred black background.

I don't think burning the fields to spot new hogweed growth is a solution
that fits the size of the problem. :) But it is easy to see when it comes
into any mulched areas.


Glyphosate is actually grass-specific, and will kill grass at levels
that leave most other plants alive. The only one more effective that I
know of is brushwood killer - but even that doesn't kill established
trees and shrubs in one go.


Glyphosate wont kill shrubs outright, but it certainly does knock
Japanese maples back, and weakens them so that they're much more
vulnerable to verticillium. But, it won't kill even sycamore seedlings...

The one thing apart from waxy plants I find it ineffective against is
buttercup. I have killed some larger areas with glyphosate and always
noticed that afterwards the buttercup is quickly back in business.

I agree completely: glyphosate is not very effective against buttercup.
Sadly. Or, for that matter, yarrow.

-E

--
Gardening in Lower Normandy

controlling hogweed
 

On 28/05/2014 13:20, Emery Davis wrote:


I agree completely: glyphosate is not very effective against buttercup.
Sadly. Or, for that matter, yarrow.

It's very slow against Enchanter's Nightshade as well.

--

Jeff

controlling hogweed
 

On 28/05/2014 11:15, Emery Davis wrote:
I mean regular hogweed, not the giant variety thank goodness.

Over the last 20 years (there was none at all then) it has installed
itself in the fields and likes to come up in cleared areas around trees
and shrubs. I've not had much luck with glyphosate, the huge root seems
to laugh it off. I've tried cutting the flower heads off, on the theory
that since it's biennial (I think) it will go away, but the seeds seem to
set anyway.

Yesterday I dug a bunch of it up as best as possible, but of course there
was a lot of root left in ground. Is it likely to come back, or is this
a good method.

Lots of info on the giant variety but not so much on regular hogweed; it
has the same chemical that causes sunlight activated burns, just not so
much of it, and the flowering stems can get to about 6 ft.

Thanks for any tips,

-E



Have you tried Pathclear yet? It should persist for longer than
straight Glyphosate and it inhibits germination of seeds.

--
Spider.
On high ground in SE London
gardening on heavy clay

controlling hogweed
 

On Wed, 28 May 2014 14:08:39 +0100, Spider wrote:

Have you tried Pathclear yet? It should persist for longer than
straight Glyphosate and it inhibits germination of seeds.


Hi Spider,

Does pathclear turn inactive when it hits the soil? I have a lot of
surface rooting trees, so don't want to damage roots.

Thanks!

-E

--
Gardening in Lower Normandy

controlling hogweed
 

On 28 May 2014 13:14:11 GMT, Emery Davis
wrote:

On Wed, 28 May 2014 14:08:39 +0100, Spider wrote:

Have you tried Pathclear yet? It should persist for longer than
straight Glyphosate and it inhibits germination of seeds.


Hi Spider,

Does pathclear turn inactive when it hits the soil? I have a lot of
surface rooting trees, so don't want to damage roots.

Thanks!

-E

Pathclear will kill trees very efficiently. That what it's main
ingredient was designed to do.

Steve

--
Neural Network Software http://www.npsnn.com
EasyNN-plus More than just a neural network http://www.easynn.com
SwingNN Prediction software http://www.swingnn.com
JustNN Just a neural network http://www.justnn.com

controlling hogweed
 

On 28/05/2014 14:14, Emery Davis wrote:
On Wed, 28 May 2014 14:08:39 +0100, Spider wrote:

Have you tried Pathclear yet? It should persist for longer than
straight Glyphosate and it inhibits germination of seeds.


Hi Spider,

Does pathclear turn inactive when it hits the soil? I have a lot of
surface rooting trees, so don't want to damage roots.

Thanks!

-E




I was just about to check, but the others have got there first. Sorry,
Emery, it looks as if you can't use it safely near your trees.

It might help if you could stop the flowerheads before they form, so
that there is no seed to increase the problem, but I appreciate that is
difficult when you're not on site full time. It looks like digging it
out and laying ground sheets are the only answers. Best to start that
at the beginning of the year, when ground sheets will starve it of
light. Once the ground is covered, you can mulch thickly to disguise
the sheet which will look fairly decorative and keep your trees happy.

I can't help wondering, though, if you could use Pathclear as a barrier
between the offending field and your own plot to help keep the hogweed
at bay?
--
Spider.
On high ground in SE London
gardening on heavy clay

controlling hogweed
 

On Wed, 28 May 2014 15:29:59 +0100, Spider wrote:

I was just about to check, but the others have got there first. Sorry,
Emery, it looks as if you can't use it safely near your trees.


Thanks Spider and others. I feared that was the case. I'm very leery of
2,4D; I don't use any sort of lawn weed+feed since they usually contain
it.

It might help if you could stop the flowerheads before they form, so
that there is no seed to increase the problem, but I appreciate that is
difficult when you're not on site full time. It looks like digging it
out and laying ground sheets are the only answers. Best to start that
at the beginning of the year, when ground sheets will starve it of
light. Once the ground is covered, you can mulch thickly to disguise
the sheet which will look fairly decorative and keep your trees happy.


OK, looks like more digging is in my future! ;) (The more things
change...)

I can't help wondering, though, if you could use Pathclear as a barrier
between the offending field and your own plot to help keep the hogweed
at bay?

Thanks, but not practical. Anyway I don't think it would work: deer love
the seed heads, then come into the garden and spread them. Not to
mention most of the hogweed is upwind of the garden proper, so the wind
will probably bring seeds in too.

-E



--
Gardening in Lower Normandy

controlling hogweed
 

On 28/05/2014 14:42, Martin wrote:
On 28 May 2014 13:14:11 GMT, Emery Davis wrote:

On Wed, 28 May 2014 14:08:39 +0100, Spider wrote:

Have you tried Pathclear yet? It should persist for longer than
straight Glyphosate and it inhibits germination of seeds.


Hi Spider,

Does pathclear turn inactive when it hits the soil? I have a lot of
surface rooting trees, so don't want to damage roots.

No. Use Pathclear only on paths (new stuff isn't much cop).

From Scott's the maker's website

1. IDENTIFICATION OF SUBSTANCE / PREPARATION AND COMPANY
Product Name PATHCLEAR 3
Common name of active ingredient 2,4-D. Amitrole. Diuron
Intended use For use only as a Home Garden Weedkiller

2,4D was in Dow's Agent Orange used to defoliate forests in the Vietnam War.

That isn't a reason to fear it. They used 2,4-D because it was cheap and
effective the problem was they used a really cheap and nasty synthesis
route that also produced high levels of dioxins as well.

2,4-D is still used in some broadleaf specific formulations.

It is the persistent components of Pathclear that will cause trouble if
used incorrectly. My father unwisely used it to spot weed his lawn once.

The modern Pathclear is nothing like as good as the original.

--
Regards,
Martin Brown

controlling hogweed
 

In article ,
says...

I mean regular hogweed, not the giant variety thank goodness.

Over the last 20 years (there was none at all then) it has installed
itself in the fields and likes to come up in cleared areas around trees
and shrubs. I've not had much luck with glyphosate, the huge root seems
to laugh it off. I've tried cutting the flower heads off, on the theory
that since it's biennial (I think) it will go away, but the seeds seem to
set anyway.

Yesterday I dug a bunch of it up as best as possible, but of course there
was a lot of root left in ground. Is it likely to come back, or is this
a good method.

Lots of info on the giant variety but not so much on regular hogweed; it
has the same chemical that causes sunlight activated burns, just not so
much of it, and the flowering stems can get to about 6 ft.

Thanks for any tips,

-E

How about eating it!

See:-

http://www.torrens.org.uk/FFF/hogweed.html

--
Roger T

700 ft up in Mid-Wales