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