If you want to shape your own root barrier, maybe contact a bamboo nursery or garden supply that sells that type of root barrier by the foot.

Ever notice that the species gets zapped by quick change to hot weather when exposed to late day sun?

mdvaden -

Thanks for your reply. I've been reading more on the Internet about acanthus and am getting more concerned. There are people who say they have been battling acanthus roots for 20 years! I'm getting older now, and I think I'd better not take the risk of planting it, even in a barrier, because if there were a problem, potentially along the line physically I wouldn't be able to keep up with it. So I'll probably put it in a pot on my patio, but then the rest of the world misses out on it. (I meant to wow my neighbors with it :-) ). Actually online the type of comments I read about this plant were "wow"!, and "absolutely stunning," etc.

I've never grown acanthus before, but I was reading that it goes dormant for awhile in warm weather but soon has new leaves again.

We successfully eradicated it. It's impossible to get all the roots, but if you're persistent it eventually becomes weakened and goes away after a few years. Keeping it drier seems to help it be less invasive, and more easily eradicated.

Still, 'Tasmanian Angel' might make more of a statement in a pot anyways. (Like "look at me, I'm special!" LOL.)

Acanthus is a summer dormant plant in Mediterranean climates, popping back up in fall with cooler wetter weather. Yes, it can be very invasive and persistent, and it laughs at Roundup. Digging it out, every little fragment of cut-off root resprouts.

A nitpicking comment re precise terminology:

Invasive means the plant is capable of spreading far beyond the garden borders, such as with Buddleia which is now in mountain clearcuts and more.

Aggressive -- I suggest that "garden aggressive" is a better term for this -- is a plant that wants to take over its home garden.

And yes, I heartily agree that acanthus is garden aggressive. I've been after A. spinosus spinosissimus for about 5 years.

Resprouts this year were only 6 or 7. I removed them as soon as I saw them.

As has been said, doing so exhausts the roots.

You're scaring me a little. I planted a. Tasmanian Angel in dappled shade bed last Spring without giving it a second thought.

My only experience with acanthus before then had been an a. hungaricus that had never really thrived in three locations where I'd tried it - just a handful of somewhat weak stems each year and only blooming one year.