How invasive is Acanthus?

I had a landscape designer plan my front yard for me, mostly she used plants I know and love (or at least like!) but one of the plants that I don't know as well which she included was Acanthus mollis. I know what it looks like so I was fine with including it, but now that I'm going through Plant Files to put all the stuff from the new landscape into my journal, I noticed that everyone from CA gave this one a negative rating because it's hard to get rid of. So I'm wondering how bad it is--should I rip them out before they have a chance to do damage? I had never before heard of it as being one of the "bad guys" but the comments in PF sure weren't flattering!

Edited to add...I'm pretty sure this isn't on an official list of invasive plants, I meant invasive more to mean aggressively spreading and taking over my garden!

This message was edited Dec 17, 2006 7:04 PM

It is very, very agressive. I had one plant when I move here, I was neutral about it for awhile, then decided I did not like it. I dug it out and tossed it. I probably have 6-7 plants continually coming up in that spot, but wait! Theres more! I think the birds maybe ate seeds, I have it coming up way on the other side of my property, about an acre away, and its down my driveway. My advice is if you like it, okay, if not take it out and make sure it never flowers. I say this because I don't think you can ever remove it. Some love it, I don't.
Rebecca

I'm lucky since I still have a chance to remove it--it was just planted 2 days ago so the roots haven't had time to go anywhere yet, and it's not blooming so I can dig it up if I need to and be rid of it forever. I do like the flower (like, not love!), but if it's going to take over places that I want other flowers then there are lots of other things I like better.

Rebecca is right!!! That stuff will start from a piece one inch long...and come up everywhere. It took me years to erradicate it. Even now, some 10 years later, a rogue piece still emerges now and then. It is also a gigantic snail magnet!!!!

If it would keep the snails off the plants I like better, that might not be a bad thing! Oh well, it's sounding like I'm going to be out there with a shovel digging it up the next time I get home from work before dark! Fortunately there are only two plants so it's not going to leave too much of a big gaping hole in the landscape. Any reco's for a good replacement that will be a similar size and enjoy the same growing conditions?

What else do you have growing around them? In other words, what "style" is your landscape???

A couple of plants I like that have that tropical look, nice big leaves, are fatsia japonica and rice paper plant. Since rice paper plant is new to me, I am in love with that one. It gets huge, eventually 8 feet or so and the leaves are huge. Very exotic looking but pretty hardy, done to about 15 degrees or so, if I remember right.

You might want to keep your acanthus in a pot. It does have nice foliage, you can clip the flowers before they go to seed. It is happy in a container on a patio, I have found they will do okay in sun or shade, like your basic weed, lol.
Rebecca

Hi, everyone.

When I lived in Montreal, I saw acanthus mollis used as a border at the botanical garden and immediately fell in love with it. I mean, what's not to like, those leaves were, IMOHO, "to die for". I tell you, it was love at first sight: a got-to-have-it-now thing.

I arranged, through one of my connections at the BG, to obtain a few specimens. They were allegedly able to withstand winters in Zone 4 and I live in Zone 5. I piled leaves on them in the fall. We had an unbelievably cold winter that year. They never came back the next spring: bummer.

My garden in Montreal comprised an eclectic collection of plants that had to meet at least 3 of the 4 following criteria: perennial in zone 4, large size, invasive and/or toxic. Why? Plants that fell in those categories are generally disregarded by gardeners. My back yard was like Alice in Wonderland on acid. I fondly remember an inula Goliath that grew to 14 feet every year and died back ever fall.

My friends at the horticultural society were horrified when they visited my secret garden. I never planted any annuals except for a row of dahlias in the front of the house, along the path leading to the front door. Acanthus mollis fit the bill on 3 counts. I even had rare specimens that fit the bill on all catgories. The grass contractor was not allowed alone in the back yard, for his own safety. I never re-planted any acanthus mollis after that.

The last time I saw acanthus mollis was in Barcelona last may, arranged in a border. My heart sank.

If you are contemplating getting rid of yours while it is still time, I would be more than delighted to acquire them. Please send me D-mail so we can arrange their shipping across the country. I've got just the place for them here.

Sylvain.

I really like my Acanthus Mollis. The leaves are really beautiful and it's easy to take care of. It does regrow easily from the roots--I often remove the leaves to tidy up the plant. It then regrows from the base. However, I have never found it to aggressively take over additional territory. The plants were in our yard when we moved here 10 years ago. They are in the same spot as they originally were and have not spread out to other areas.

If I compare it to other aggressive plants (like mint, for instance), I would call it stubborn but not agressive.

LOL...Alice in Wonderland on Acid...
"...Go ask Alice....when she's ten feet tall........"

Hi Lilystorm,
I found your post most interesting, I used to live in Santa Clara. I had this plant there as well, was there when I bought the house. Now the interesting thing is that it was not invasive, stayed in the same spot and when I thought it was not being a nice nieghbor I cut it back and we got along fine. I find it odd that here on the Oregon coast where its colder it really is a monster. I am used to people telling me plants are invasive and here they barely survive. If it behaved like the one in Santa Clara then I would let it go. Where ever its at, you should make sure you like it before putting it in the ground, its probably not easy to remove anywhere.
Rebecca

I wonder if it's something about coastal climate vs inland? Seems most of the people who've had bad experiences with it live closer to the water. So maybe it would be OK where I am since I'm even a little farther inland than Lilystorm. Any other thoughts from people who live a little farther from the coast? If chillier winters and hotter summers help keep it in check, then I may keep it. I don't mind something that's a little stubborn, just don't want it if it's going to take over my garden!

I drew the line at bamboo (the runner kind). Well, that's until a friend of mine dropped off a clump of the running variety that could go to over 10 feet tall. I couldn't resist the gift. I did plant it in a large galvanized steel tub, where it did very well.

When we moved, someone at the horticultural society wanted the tubbed clump so we dug up the whole thing - tub and all. I hear she wasn't as careful as I had been. She is now fighting a bamboo invasion of biblical proportions: Caveat emptor. Let the buyer beware, even if in this case no money changed hands.

Sylvain.

A rhizome barrier wouldn't be a bad idea... then you could probably plant this one 'safely' in the yard. . I have seen them planted inland in the San Fernando valley without a whole lot of problems, but they rarely looked good... this plant is a water lover, and it loves wet, clay soils. However, if you don't water much, it won't go very far... but it won't look good, either. But if you give it a lot of water (here in So Cal, unlike in the northern areas, water is a choice, not a way of life, so you can control this, and even running bamboos by witholding water)- look out. I had it planted in inland southern California, but under the protection of a shade tree, and in an area that got watered a LOT (had a ton of palms there). And though the plant was easy enough to chop down every time it grew up, it was there, and there to stay, and kept moving out into the yard year by year. I finally put a paved path around it and that stopped its outward spread, at least. But it made for intense root competetion with the plants in its area. No matter how much I dug up, it never even seemed to affect it. In fact, that seemed to stimulate it into growing more thickly. Scary plant!

Mine gets average water and looks good except in the heat of the summer. When I don't like the way the leaves look, I take them off and get rewarded with new beautiful leaves.

Don't get me wrong--it's not my favorite plant ever, but I like the foliage effects and have never felt like it was threatening to take over the yard. I have blackberry vines and other plants that are trying to do that, so I know what aggressive is... LOL

Maybe I will keep them then, sounds like they are less aggressive farther inland and I do like their looks. But I like the idea of putting a root barrier in just in case. I have lots of nice clay soil so that should make them happy. I don't water things a ton and most of my landscape will be somewhat drought tolerant once it gets established, so we'll see if they are happy with that or not. But they are in the wettest part of the yard, so they'll get the water I give them plus any excess irrigation water that runs down the hill so I think they should be OK except maybe in the hottest part of summer. I'll wait and see if any other comments come in before I make my final decision (the next day that I'll be home before dark will be Friday, so I can't dig them up until then anyway!)

ercrane,
I am thinking you worry too much, I do not think you could kill this..lol. And your are right, the foliage is nice if you keep the snails off it and it doesn't get heat burned. Lots of people really like it, but I would dig it up if its new and put it in a pot, then put the pot in the ground, perhaps with a barrier. Just in case you grow to hate it and cannot remove it.
Rebeccanne

I think everyone is correct about it being more of a nuissance in coastal areas. It IS a water guzzler, like Palmbob says...and it definitely thrives in wet clay soils. I see it growing here in the marshy areas, and is really is beautiful when it's lush and in bloom. The funny thing is that it never seems to get eaten by snails in those areas...but by then end of summer they're pretty thrashed looking.