Good thread! I've seen similar in the past, but with so many new plants being introduced, it's a good time for an update.

I believe that my biggest mistake has been Euphorbia cyparissias. I moved here from the midwest, where euphorbias are not that common, and fell in love with them. So I bought this cute little fluffy thing in a 2' pot at Molbaks (shame!).

It has since taken over my front yard. It *is* a pretty plant in small, contained clusters, but unfortunately it has free rein in my yard. I still love the alien-like buds when the new plants push up in the spring... and the late spring... and the early summer... and the late summer, but if I had it to do all over again, I would plop it in a pot on the deck.

Here is a link that might be useful: description of cypress spurge

Some of my "cheep-o" friends love to dig up plants at sites that are about to be bulldozed into new lots. They convinced me to go along, only once. When I got to the property, the crew gave us the thumbs up and I decided I would rescue a colony of sword ferns from certain death.

It's been about 5 years now, and the sword ferns are perfect, the buttercup that I unintentionally planted, is a nightmare. I managed to get most of it, but every year...

Lily of the Valley!

Oh, this is a funny thread!

Some ground cover (or so I thought) started growing around my primroses. I had a nice primrose garden, and worked hard to encourage growth of the new mossy-looking stuff. Goodness, it went to seed or something, and started popping up all over my flowerbeds, clear across the yard even! I'm fighting it, still. Horrible stuff. Ripped it all out once I figured out it is awful, but didn't get it soon enough. I hates that stuff, I do!

Martin

NWNatural - Me too, I found some mature blueberries after much ado, and they brought along their buttercup friends. I found that a thick coating of mulch did most of them in, but every year.... And I better not even think of disturbing the soil in that area!

Martin - I think I have some of that too, it made it into the lawn in the thin patches, but I will win.....maybe.

Has anyone else out there had that experience with Lily of the Valley? If so I am going to light a fire in a special part of my yard. I have had it there over a year, and so far it hasn't even bloomed, or grown much.

Lily OTV has been OK for me in a spot it doesn't compete with other plants. It has such a short bloom season, though, or else my plants are too crowded to bloom much.

Lamium galeobdolon- love that silvery variegated foliage, but it has been a nightmare for spreading and overrunning other plants. I've decided to go for total elimination if possible. I dig ones that come up in the areas I've cleared and plan a newspaper blanket for the solid patch this winter. In the right neglected dry shade location it can look lovely, though.

Herb Robert- It looks great but self-seeds widely and turns into a pest of gigantic proportions.

Lemon Balm- not only the tenacious roots of the other mints, also invasive pests, but also self-seeds and comes up all over other beds as well.

Back when perennials were my passion, I planted a few I wished I hadn't - plume poppy (still a dramatic plant but such a thug!), a perennial sunflower related to Jerusalem artichoke that took me YEARS to eradicate, tradescantia (about which I have nothing good to say) and a few, too aggressive vines like golden hops and trumpet vine. Not much else has proved to be a problem, unless you count not picking the correct placement the first time (or the second) and moving the same plant around several times. And there have been a few plants that reseeded much more enthusiastically than I would like - eryngiums, with their nasty tap roots, euphorbias that pop up everwhere, a couple of ornamental grasses. But gardening is all about making mistakes and learning from them :-)

I have always wondered about the problems folks have reported with LOV as well. My own clump has never been very aggressive, sending up a few, relatively sparse leaflets each season and some flowers. Grown in a situation I would have thought ideal to LOV. Another clump of the variegated leaf form is doing much better in a less hospitable location, but still posing no threat of spreading rampantly.

Oddly, although my garden seems to be well suited to the growth of most other plants and they are all robust and doing well, groundcovers establish very slowly and seldom demonstrate very aggressive spreading tendencies, even those like vinca, creeping Jenny and LOV that other folks love to hate.

Artemisia, I think the variety was limelight? I had no idea it would grow so fast or spread so aggressively! I haven't put a lot of effort into it yet, but I think digging it out will be really tough. It's got runners going everywhere!

In ten years my little patch of LOV has smothered many more desirable perennials including ferns, bleeding hearts and hostas. It is in somewhat dry shade. It has spread over ten feet along this bed. I love the fragrance but it only blooms for a week and the leaves look really ratty from slugs and root weevils too. IF I can ever get it all out, I'm going to grow the pink and the variegated versions in pots.

I keep digging and I keep spraying with Round Up but I'm not making much headway.

If anyone in the Portland area wants any, there is plenty available at the moment.....

My LOV is in full sun, maybe that is why it is not thuggish there. Odd how we can have different results when we all live so close. I guess it means that most of these plants just have the potential to be invasive.

Artemisia, so many plants in that family are so well behaved. I guess there is always one bad seed.

One year I planted a cover crop mix that included rye. That was a mistake. The rye is ugly, and I was afraid it would turn into foxtails that would dig into the dogs' coats and burrow into their flesh, and there's no getting rid of it once it goes to seed.

The other huge mistake was to build raised beds and then fill them with wonderful soil without first putting down wire mesh to keep the voles out. The voles just went to town in all that nice soft dirt full of potatoes and carrots. I couldn't harvest anything. On a similar note, letting the chickens run freely through the yard is picturesque but they're worse than dogs when it comes to digging up the veggie garden.

Not an invasice, but I plated wooly thyme in between some of my footpath stones, and instead is this nice green tuckin inbetween stone, it looked like big blothy spots. Yuck! Then they grow all those weeds in them, which you can't get out. The wooly thyme ended up biting the dust.

I'll second the motion on Euphorbia cyparissias being a scary plant. I bought mine at a well know specialty nursery....such a pretty airy plant with blue green foliage and hints of red plus the flowers. it seemed to be the perfect groundcover looking wonderful as it spread between shrubs. After one year in the ground it began spreading into the grass and I realized that it was "too good to be true". It took 3 years of digging out every sprout that appeared but i believe it is finally gone. jwww

Own root shrub and old garden roses right next to the driveway.

Just about any knotweed.

Running bamboos can be amazing, sumac and clerodendrum also apt to venture forth suddenly. Then there's Aralia elata...

I have the Euphorbia cyparissias and it does spread rapidly, but as long as I think it won't seed around I will leave it because it is an isolated bed that needs a groundcover to defeat weeds. It does look nice. My garden has a lot of invasive plants just because I need plants that succeed in difficult situations like dry shade, infrequent watering in our long dry summer, and weed pressure, and they do.

Some of my drought tolerant (very little to no water in summer once established) invasives I like-
Vinca major in the right place- in a ring around tall cedars;
Vinca minor, much shorter and more mannerly, ditto;
Symphytum grandiflorum also dry shade and to suppress weeds around trees in my orchard, for photos see my post in the groundcover forum;
Phalaris arundinacea- will beat out all weeds for difficult borders like along a driveway strip, can be mowed down if it gets too tall, nice variegation, dormant in winter so needs to be trimmed;
Aegopodium podagraria or Bishop's Weed- lovely variegated foliage, so far has not spread by seeding, fills in well, looks great next to the Phalaris, dormant in winter;
New Zealand Burr-very low-growing, ferny leaves, I have a couple- Acaena saccaticulpula Blue Haze- blue-green leaves, makes burrs; Acaena inermis purpurea- purple leaves, I haven't seen it make burrs; I have these in a mini rose bed and it does seem to hold the weeds back some but not the really tough ones like sweet clover; related to Salad Burnet which is a self-seeding nightmare;
Ajuga- lots of varieties, some more spreading than others, hold weeds back some but not totally, so vigorous I worry about it under roses.

Here is a link that might be useful: Symphytum grandiflorum

A few years back a friend of mine gave me some seeds from a beautiful mallow or malva zabrina. It is a beautiful tall bushy flower; purple with pink striping blooming early all the way through summer and fall, but it reseeds profusely! Now it is everywhere! It is now throughout my courtyard flowerbeds, and in our driveway which is gravel. I have given many of the plants away to friends too - whoops~ I am sure that I will be fighting this for years! I feel so guilty for giving it away too!

Aegopodium podagraria or Bishop's Weed-had it at a rental house, horribly invasive for me there.....Lovely foliage though

Mary, I tried growing Malva Zebrina but it didn't survive the winter or reseed for me. But I have a pink Malva that gets 4 or more feet tall. I looks pretty good for a while then starts flopping and going to seed, and reseeds all over. I'm about to try to get rid of it.

I've spent 5 years trying to get rid of the Aegopodium podagraria that previous owners planted. Some reverted to non-variegated and is even more invasive. It's almost gone now but a few patches continue to pop up.

It also took as long pulling out English Ivy and hardy geranium. These too still pop up occasionally, 5 years since starting to pull them out.

Scilla hispanica is more insidious, since it goes dormant in the Summer and I forget about it. Each Spring I pull out tons of it. Little bulbs break off, and reestablish in the same location. Now that I've reduced them to a few areas, I'll probably leave them alone because they do look nice and take no care at all.

Moonflower vine. Not me, but a previous resident. Supposed to be an annual but in my yard in PT it wasn't. Or it was moonflower's evil twin. I'd had part of the tiny yard rototilled before I knew it was so invasive or the extent of its spread...you guessed it - like a starfish, every little bit of root spawned its own plant. It was awful. The sweet autumn clematis was also a real bugger. But the moonflower vine was the worst! I bet it's still there, years after I've moved on...

As much as I love euphorbias, I beginning to rethink their presence in my garden. I managed to avoid the cypress spurge, E. cyparissius, but I still have seedlings of E. dulcis 'Chameleon' popping up years after using it in a container planting. The bigger problem now is seedlings of wulfenii, which are everywhere and grow with such speed that if you don't get on them immediately, you have a full grown plant on your hands before you know it! The mother plant was removed a couple of seasons ago, but these seedlings still keep appearing and at considerable distance. I'll concentrate now on the sterile hybrids instead for my euphorb fix.

btw, a planting of variegated 'Tasmanian Tiger' has done very well and is very robust with no signs of seeding (which I assume would most likely be nonvariegated). It is planted adjacent to a Carol Mackie daphne and the contrast in variegation between the two is really quite striking. I can't remember if I planned the combination or if it just seemed like the best spot for the euphorb, but whatever the motivation, the placement turned out to be rather smashing!!

Gardengal...When in doubt, take credit! is my credo.
(for serendipitous combos)

So, Pam, tell me about euphorbia 'Rudolph,' which has a large presence in my front garden. :) Will kinnikinnick and Rudolph coexist peacefully?

As far as mistakes, I wish I had chosen vine maples more carefully: in the fall for color, and with an eye to branch structure, and with understanding of mature size. I just took out the third and final 5-year-old vine maple.

Thanks riprap - since it is MY garden, I'm more than happy to take the credit but many of my better plant combos tend to be more serendipitous than actually planned :-)) Ma Nature is obviously a much more talented designer than I!

Marcia, IMO 'Rudolph' is one of the better new euphorbs on the market - great coloring, modest stature, resistance to PM and since it is a hybrid, less chance of wanton reseeding. It should coexist nicely with the kinnikinnick. Is it time for breakfast?

Name the day. :)

Bishops Weed! glad I moved. It was coming up in the grass.

Chinese Wisteria, again, glad I moved. I drive by the old house and shudder! I told them to prune it constantly, but they didn't listen -serves them right for being lazy. I'm convinced, the tenticles will consume a small child.

Passion vine is very invasive, in my greenhouse, it's growing through the floor and popping up outside in the lawn - about 6 feet from the greenhouse.

Speaking of euphorbs, beware Gopher's Purge. My plants were getting 5' tall, loaded with seeds that sprong off everywhere. Then I started getting a skin rash from the sap. My 18 mo grandson brushed some when visiting and developed blisters that looked like burns, which freaked out my daughter. I'm on an irradication program and see them coming up everywhere still. I haven't had much reseeding from wulfenii, though.

I moved a Chinese Wisteria into the lawn away from my deck, and they are still coming up from the old roots several years later. Last winter killed off the Passion Vine, though, which was getting too vigorous there too. Now I have a climbing rose there that may turn out to be a house eater.:-)

I refer to certain enthusiastic self-sowers as my "be careful what you wish for" plants. Myosotis sylvatica (Forget-me-not) is one that I couldn't get started at all until I ripped up a few plants that were growing alongside the road and planted them in my garden. Now I rip it out by the wheelbarrow load. Gallium oderatum (sweet woodruff) is another thug that I now rip out in huge mats.

Princesskatja, I wonder if you have bindweed (Convolvulus arvensis) instead of moonflower. The flowers are nearly as large and a quite lovely, but the vine is a horrible, choking thing. It's pretty common around here.

Here is a link that might be useful: Field bindweed