Topic: Problem with Rose Bay Willow Herb

[cacran]

We have some land which was covered with Rose Bay Willow Herb. I cut it back with a sythe then strimmed it I know it will come back.
I don not want to use weed killer really. I wondered if I could cover it with cardboard, then with soil. Would that kill these weeds off, do you think?

[gray1720]

I've not had to shift rosebay willowherb roots, but they're pretty big, and it's a PITA because it seeds so vigorously rather than spreading by root, so I wonder why you don't dig it out?

If it's because the ground is hard (not sure which side of the great rainfall divide you are), I can't see why you don't go for the cardboard. Though it seems a bit of a f*g moving the soil on and off it - or do you mulch the cardboard in?

Given that black plastic will even kill off couch grass (bindweed, sadly, is a different matter, I swear it survives for decades in the dark) I think anything excluding the light will help kill it, though as there's a lot of energy in those big roots it might take a while.

Adrian
 

[Digeroo]

Rose Bay has dreadful roots, and it is very easy to break a bit off and leave it behind.  We have it in the garden, but once you dig it out and then persist in removing it every time it raises its head it seems to go away.  Certainly not as difficult to shift as bindweed.   I also think digging it out is the answer.  It is a root so excluding the light will be no use, I think it will just pop up again when you remove the cover. 

[cacran]

Oh dear, I was afraid you would say dig it up. You should see the size of the plot, and it's full. Seems funny that it has not spread on to the other gardens, which but up to it.  I think it will have to be the dreaded weedkiller!!!

[Robert_Brenchley]

It's horrible invasive stuff, but black plastic will kill it.