Another vote for Corydalis heterocarpa, and it has a horrible, sickly sweet, retch-inducing scent to the leaves released when pulling out the masses of unwanted seedlings. The labrador violet is a profligate seeder and makes tangled mats, though it's in bloom now and I must say it unifies by running along the pathway. Just gotta keep it out of the main beds. And Stipa tenuissima, renamed but can't remember it, seeds itself everywhere and in some of the most striking places, but enough's enough.

I am sorry to hear about Clara Curtis...I just got some last spring and loved it in the fall...Oh my, now I am worried I will have to be digging it out.

Ajuga - esp the type with bronze/purple foliage. Spreads by runners and likes to infest green grass, too. Impervious to Roundup.

Forgot Lamiastrum (yellow archangle)...ground cancer.

Lariope! It has taken over! I keep pulling it up, and pulling it up and DIGGING it up...and...it STILL keeps coming!

All you folks who want to get rid of the malvas might want to take a few deer off my hands. They not only ate them, they dug them out by the roots. They eat most everything, but this was a little bit more extreme than their usual table manners.

My favorite hate-it plant is ajuga which I planted 36 years ago and have been trying to control/eliminate for the last 34.

George

Amen to plume poppy. It took me a couple years to get all of mine out. Each tiny piece of root can grow a whole new plant.

I think it depends somewhat upon the site. Chasmanthium planted on a dry,rocky slope, behaves well for me. However, one plant that I am still battling is Houttuynia cordata, which seems to like it everywhere in my yard.

Susan.

Plantago major 'Rubrifolia'/'Atropurpurea' - purple-leaf plantain. It's the purple version of a common weed. It's a lovely plant but there are always a few that I forget to deadhead, and they seed absolutely everywhere (especially in the lawn).

Reading all these posts, it seems like what is invasive depends quite a bit on one's climate. Shadyplace mentioned Lobelia siphilitica. It's native here, growing at stream edges and I'm always trying to get more of it..lol! And my liriope makes neat litte clumps and never seems invasive.

vegangirl, you make a very good point, a cherished plant in one zone can be an invasive monster in another. One man's trash/another man's treasure. Think twice before planting goes both ways.

A......

I'm a beginner & you all have me scared half to death. Besides other plants I'm planning on planting (& I'll read this post before purchasing anything) I planned on planting Pennyroyal Mentha pulegium (in the mint family) ... to help keep the fleas down (not only have dogs, back up to a wooded area that has lots of insects). I haven't read this particular plant name mentioned in this post, but am I nuts to plant this plant - I read to avoid it becoming invasive, plant in containers or in confined areas.

I also saw the area that stated where I could look about invasive plants & I'll go there.

lily of the valley...not hard to pull up but the roots extend for miles. You can pull up one and the root will run a quarter a mile lol :P.

Great...I've seen three plants listed that I was intending to purchase this year. Jacob Cline Monarda, Clara Curtis Daisy and Yarrow. Do I need to rethink that decision? :)

I have never had a problem with Clara Curtis where I live, it actually died on me after two years. :o(

A......

So the bottom line is....it's hard to know!

Yep. Many of the plants listed here I'd actually like for them to grow some! Like lily of the valley. I have it in dry shade, where it is very well behaved. Liriope I am considering getting rid of this year because it never grows. One plant that seemed to creep everywhere was Sweet woodruff. It would be lovely planted under trees in an open area. Too vigorous for a flower bed. Ajuga is well mannered for me and gorgeous. I couldnt do without this plant.

Jen

That's encouraging! Thanks!

When I first moved to this property, there was a small patch of lily of the valley growing in dry shade. It did not even flower. After 14 years and lots of organic matter added to the garden, the Convallaria blooms like crazy and has turned thug. I am now eradicating it and replanting small bits in sunken pots. (I can't bring myself to get rid of it completely!)

I was going to try sweet woodruff, but in a pot. Hopefully that will help.

A word about Bishops Weed/Snow on the Mountain. It is sold in garden centers here as a groundcover, and it will most definitely cover the ground. So well, in fact, that it seems impossible to get rid of. Sun or shade. I'm in the middle of trying to eradicate it (last summer, this spring). It laughs at RoundUp, and I'm running out of ideas. I'm impressed by whoever said they got rid of the Bishops Weed.

But unless you have an area with poor soil (sun or shade) that you need covered, that you'll never want to plant anything else in again . . . I wouldn't go for the Bishops Weed.

I've got Sweet Woodruff in a cement planter outside my back door, When it finishes blooming I cut it right down, then it grows again, looks neat and tidy for the rest of the season. I usually put pots of something or another on top of the S. W., the S.W. softens the look.
I would imagine one could plant summer flowering bulbs with S.W. in a container, could look very attractive.

A......

I can't get sweet woodruff to grow for me! I've tried three years running to get it established, and was just out the other day looking where it is planted, thinking how I may just finally give up, because there is no sign of life.

Dee

Anyone close enough to Baltimore can come and dig as much Sweet woodruff as they want...About the Bishop's Weed...my husband spent a long time literally pulling all of it out by the roots...you have to be diligent but it works.

Happygarndparent, talk to your local extension agent for information about what's either a garden pest or invasive in your area. Garden pests are like mint; they become a nuisance in your garden but don't actually threaten native species. Invasive species are different - you may not have much of a problem in your garden, but birds could be spreading seed far and wide and creating a much larger ecological problem. It's important to understand and respect both kinds of plants.

Usually your state's land grant university has a list of problem plants for the state on its web site. The extension agent should know about that.

Gymnaster savatieri (Japanese aster). This started the season as a 1-quart perennial and ended it as a solid mat of rhizomes 6 feet in diameter. Its first year of bloom was unimpressive, which is perhaps not surprising, given that the plant was obviously putting its energy into world domination.

Nothing I read about this plant said it was a thug -- perhaps it's my garden conditions (thin, rocky, alkaline soil).

Lily-of-the-Valley is one of my favorite flowers. I have a hard time getting it to grow.

About the only plants I have trouble getting rid of are honest to God weeds, like Buffalo Bur. I spent most of last summer pulling it and barely made a dent.

I live in east central Mississippi, and can add a couple of thoughts about some of the thugs mentioned. Liriope comes in two forms: runners and clumpers. The clumpers will never give you any problem. The clumps will get bigger, but are not a problem. The runners..........well, they are pretty in the right place, but you'd better like them there, because they're going to stay a long time.

Clara Curtis Chrysanthemum is a spreader, but as long as you root prune it each spring, it's reasonably manageable here. Ditto for Mary Stoker. If in doubt, try this: plant a division of the plant in the middle of a large nursery pot: (3 to 5 gallon usually) and sink the pot into the ground. The sides of the pot will contain the stolons. Each spring, lift the pot, reduce the division inside it again and plunge it back into the ground. Do check the pot every year. I have had a few like Setcreasea, for example, actually split the pot by the end of the winter.

Another one to be very careful about is Coreopsis integrifolia. It's a lovely plant, but boy does it run during the winter. For newbies, it's a good clue to look for the word "stolonifera" in the Latin name of the plant. If that's there (and it won't be for all, by the way), it's a good clue to start the plant in a sunken pot until you see what you have. Also, if a plant catalog uses the word "vigorous", "quickly spreading", or says something like "will make a three foot clump in one year", they are tactfully trying to warn you. Remember, they are in business to sell plants, so they are trying to balance their desire to sell with their desire to be truthful.

Amusingly enough, my sis has Bishops Weed/Snow on the Mountain planted up against her house [was there when she bought it]. It is just barely suviving & she has never done anything to control it.

One plant that hasn't been mentioned here but whose post has once again resurfaced ... yucca. Vile vile plant. If you have any doubts, read the post on it.

Alstroemeria psittacina is driving me crazy. Anybody want some? The hummingbirds love it. Also, my Hakonechloa macra is spreading into my other plants and it's really hard to pull out.

Tradescantia ohiensis aka spiderwort... I dont know if this plant has been mention but it is the plant from hell. It is even growing in my gravels under my carport. I sprayed them with a weed killer. They came back healthier than ever.
And to think it started off with a one inch clipping. And if you dont dead head them they are so ugly. Anybody want some? lol...........
Ladysmom

Bishop's weed, even the variegated one. The Latin name is Aegopodium podagraria, and the English call it Ground Elder (when they aren't simply cursing it). Okay, so the variegated one is a good groundcover for very tough places if you don't want to grow anything else there. And it's attractive. I'd consider using it in dark, dry, shady spots in urban plantings, alongside buildings and stuff like that.

My comfrey, my 'Clara Curtis' chrysanthemum and my Plume Poppy are all big, but not too far out of bounds. Sometimes it's good to live in a desert...

I use the Plume poppy where NOTHING else grew, and it's still the only thing that will grow there, but manageably. The Comfrey went in a similar spot right up against a Tree of Heaven for competition. The Chrysanthemum is out front in the xeric garden, and that holds it back a bit.

Oooh, I'm glad this post was brought to the front where I noticed it. Interesting stuff, and (too many) plants I have here. Purple coneflower? I had no idea. Achillea? Again, no clue. Sheesh, I'm in for trouble.

At the moment, I'm battling bishops weed, as noted in another post. ,b>shadeyplace - you said you eradicated it by pulling it up by the roots? I am surprised, I have been unable to get roots when I pull, the stem always breaks. Do you have a special trick for pulling?

Another I would add to the list is the common orange daylily - I don't know its scientific name, but you often see it by roadsides. It took over an entire bed before I started dealing with it. Yanking it out was useless, it left rhizomes that grew new plants, we eventually resorted to roundup with this guy.

Orange ditch lilies! My husband even dug a TRENCH and put roof flashing between my garden and the fence along my neighbor's driveway. They have two inches of soil and have planted ditch lilies, purple loosestrife, bishop's weed and geraniums there.
It's enough to make a grown woman weep.

Although it is beautiful in the early summer Missouri Primrose (Evening Primrose)seems to want to take over my herb garden. Every year I yank it out and every year it is back! The same is true of Chocolate Mint ( I should have known better).

Did anyone mention goutweed ? Ought to be illegal.

Morning Glory, for all its beauty, is also a bit of a pain. Looked super for the first few seasons but after that it came up everywhere to choke other plants. It needs to be planted all by itself somewhere.

Labrador violet (or is that newfoundland violet) gets into everything, including the driveway and isn't even as pretty as some other violas.

Corydalis Lutea seeds like crazy, but it easy to yank by just scraping around the surface of the soil while the seedlings are still tiny.

Raspberry. Not meant for a small garden. That said, if I had the property, I'd have brambles everywhere. I love fresh berries.

For many plants that I do not trust, but want (mint, ribbon grass, verigated japanese knotweed), I plant in pots with the rim set 1-2 inches above the ground. Some of these pots are quite big (15 gal), which gives you a nice sized clump. My mint is double potted because I really don't trust it.

I get these pots by going to a good nursery which has a landscaping division. Their dumpster is filled with used pots.

If you need to get rid of lily of the valley, just plant some pachysandra.....

Prairie Love, don't fret about your perennials. As mentioned earlier, part of it depends on your zone. I see your zone is a lower zone. I'm in zone 5 and coneflower and achillea are not invasive here. I doubt you will have any trouble there.

The yucca took four or five years to kill and multiple doses of everything. Sometimes I think it is only sleeping and has become one of the "undead" in horror movies. I want to add chameleon -- it's a five year effort and still crops up here and there. Perennial geranium is persistent too. I gave up on campanula, though it is controllable with vigorous, constant pulling. Mint belongs in a container, along with every other invasive plant. Good luck to us all.

I love my Ajuga and my Tradescantia. My mint is planted under the deck where it is not bothering anything. It won't grow in the sun- too hot here. My vote for most invasive goes to Wisteria!!! The Chinese kind- it spreads by seeds and by runners and can run over the entire yard. Oh it takes over and you can't get rid of it! I am so glad there is none in my yard. Brandy

No one has said Queen Anne Lace yet? Allow me! I am going to launch a major offensive again this weekend. This year I plan to break down and use chemicals which I have avoided in my former attempts to tame the Q.A. Lace. Don't plant this baby unless you are ready to be invaded.

Kate

I vote for Tamerask. When I first saw it one spring, I loved the pink blossems. No more! We have a creek going across our 5 acres. Years back, some eco-nut planted Tamerask all over the creek beds in our area. It has taken over, crowded the creeks and takes over our driveway and the road out front. We cut it back, but it comes back each year to claim more of our land.

A tip for those with Queen Anne's Lace: this was told to me by a neighbor who owned a cemetery, so he knew a lot about grounds care. We were plagued with this until learning this trick. It has a root like a carrot. If you pull it before it blooms, the root will break and you will get more plants. But if you pull it while it's blooming, the entire root will come up!

can someone tell me what artesmia is? I just purchased one of these today, because the clerk said it was beautiful. I am researching trying to find info on it, and can't find anyting , except it mentioned in a post here....
Thanks...
sandraj1955@bellsouth.net

sandraj, it depends on which Artemisia you bought. The little ones like 'Silver Mound' are pretty well-behaved. The Artemisia ludoviciana ones can get thuggish in favorable conditions, as can the variegated green-yellow one being sold in a lot of nurseries. A. tridentata (sagebrush) requires excellent drainage, bright sunlight and very low humidity, so unless you live in the far West, you might have trouble growing it at all.

I hate Jewellweed Can't get rid of it! But it is good for poision ivy rash.

To those of you who are struggling to get rid of your Bishop's weed, my sympathy to you and good luck - you will need it. It certainly does not need the Bishop's prayer to survive. I have observed that a single viable node of a tiny piece of rhizome is enough to grow into a new plant.

The only solution to the problem is to move house, hope that potential buyers are not knowledgeable about the resilience of this plant.

We inherited three horribly beautiful but horribly invasive trumpet vines. We are in the process of trying to rid our yard of them...yeah right...we'll see. I got a plant from a friend and it must have had a little piece of mint root in it because now I have mint growing in a flower bed! It has only been there one year (I noticed it last year but was pregnant and couldn't do anything at that time about it) so this year I am ready. What are my chances of simply painting the leaves with roundup and letting it take it into the roots? Do I really have to dig and dig and dig???

I've gotten some surprises since I moved from Northern CA to OK. Plants that were invasive in CA are not here, and vice versa. My all-time hated plant for taking over the world is Hypericum, in any of it's varieties. I would never ever consider planting it unless erosion control was desperately needed on a hillside. The root system is very tough and can turn into a nearly solid mat, killing anything else in its path. Once it's really established, I think it would take a tractor and a lot of weed killer and several years to eradicate it.
Lily of the Valley can spread out over a huge area and be all but impossible to control. Coreopsis in CA is like a weed. Start a plant or two and it spreads everywhere. Here in OK it doesn't seem to be nearly as much of a problem. In fact, I tried scattering seed in hopes that I'd get a crop of new ones, but nothing happened. However, I found that the spiderwort likes this climate and had a dozen babies the first year.
The remaining ones are vinca major or minor, which can be really hard to control; sweet woodruff that was mentioned above, which has such tiny roots that it's easy to keep where it belongs; monarda, which began as 8 plants and is now over 8' wide; and evening primrose (oenothera) which spreads like crazy. I'm using it to fill in an ugly patch and it's doing a very good job of it, very fast. Six little starts last year turned into an area that's about 8'long and 5' wide. Also, honeysuckle in OK is an invasive weed, climbing over, under, around and through anything in its path. I'm growing Goldflame, which is well mannered, with an extremely long bloom period.