I had two clumps of Acanthus in different parts of my garden that I wished
to remove. I tried digging it up, as you did, but the roots are long and
any piece left in the earth will send up more shoots. So I tried a
different method for each of the clumps and they've both worked - I'm
acanthus-free this year! I laid thick black plastic sheeting (I used an old
compost bag, spread out with the black interior face down) over the growing
shoots from one of the clumps, securing the sides down with bricks to shut
out all light - and left it in place for a couple of years. I put some pots
of flowers on top to disguise the plastic.

The shoots from the other clump I sprayed with Round-Up - they do die down
but will send up more, which you need to spray again until the root system
is killed off. The time to do this is when the leaf is growing, from late
spring onwards. It's not too late now but you may have to repeat from
spring next year, and that should do it.

I don't know why the experts on the gardening programmes enthuse so much
over Acanthus - it's spiny, and invasive, and not easy to get rid of. Mind
you, I can appreciate it for its structure - but only in the large garden of
some stately home!

NB. Before spraying the leaves with Round-Up, you must cover adjacent
plants (I put plastic shopping bags over them) as it's a systemic herbicide
and you might otherwise lose them. Obviously, take the bags off afterwards
once the spray has dried on the leaves (you need only a fine spray - don't
over-wet the leaves). Avoid a windy day as you will get spray drift, and
spray when there is unlikely to be rain for several days.

PS. I found Round-Up also successful at killing off Ground Elder, though it
took several seasons. I had loads of it in my garden and now I have none.

"p.k." wrote in message
...
Hazel wrote:

It laughed at Root Out, although I couldn't do a real job with it due
to other plantings

Hazel

I've had success with hoeing any new bits that appear - eventually it
gives
up after ho-hoing back at you for a few years!

pk