my moterr in law , nothing grows there now lol

In mine it is without a shadow of a doubt the yellow Corydalis lutea.
It self seeds everywhere i look :-(((((((((((

Is it too late to dig her up cliffo ? Lmso, sorry couldn't resist.

Sansevieria would probably grow there Cliffo, The name of the one plant I regretted planting escapes me, but it is low growing with red/cream leaves ans small white flowers. I had to dig out an entire bed to get rid of the tiniest piece of root. can someone name it?

Right now, I regret planting Ranunculas ficaria 'Brazen Hussy' seeds everywhere and difficult to remove.

Acanthus -bear's breeches- for me, the more I dig it up the more it spreads. Oh and grape hyacinths in my rockery.

no good Heron to asinine , nothing wrong with the spelling lol

Passiflora. I have fought for years to get the monster out of my hedge. All my assassination attempts have failed. As soon as your back is turned, it reaches out with a tendril, coils it around your neck, and attempts to strangle you! And it LOVES weed killer!

A dwarf Bamboo called Sasaella ramosa. It only gets about 2ft in height but has already spread about 10ft and will keep on going. I'm going to have to restrict it with a barrier me thinks....

You could always just slab over that bit Cliffo although I would perhaps use coloured slabs over that particular section so you will know where you done the errr . . . . . planting

Weedpatch I have a pink geranium that no matter how small a section I plant it just completely takes over , so that would be mine

Everything!. I should have had the whole area covered in tarmac and made it into a car park!

LOL

can'tdo anything there without her interfering lol . sorry Weedpatch

Heron - that sounds like houttuynia cordata 'Chameleon'

I think I agree with Bluespruce - that celandine is a nightmare

For me its Houttuynai cordata chemeleon I even wrote a blog on it taking 5 years to get rid

Houttuynai 'chemeleon'.....'ll bet thats the one Heron is talking about...I have been having a battle with it for years...and it smells horrible!!

Orange Hawkweed, Viola labradorica, Sedum acre, Fairy Foxglove, Horsetail in the pond (true), Scillas, Fairy Thimbles, etc, etc.
No, don't really regeret planting them but they can take a bit of controlling at times.

Fargesia. Planted 3 years ago by a fence, did nothing the first year then spread deep under the fence gravel board into neighbours. Fortunitely into a raised bed. Dug it up which took hours and after much blood later (from skinning my fingers on already cut down canes hidden amongst think mass of bamboo leaves) it came out. Dried out soil, left bamboo leaves everywhere and the mass clump of strong fiborous roots left a crater in ground
Still appears ion the same spot now. Neighbours killed hers off but it wasn't as established as my side!

I haven't planted it but when people plant low growing roses in soil that is full of couch grass and you end up more damaged than the couch grass! Evil ideal and should be banned.

at the moment I cant think of one but given time I am sure there will be one. a potential might be the 'red dragon' or the yellow archangel. but so far so good.

i didnt plant it but i still have couch grass to get rid of.

What an intersting collection.
Don't really think your dilema can be beaten, Cliffo. Although you made me laugh Owdboggy. I feel like that myself sometimes.

Houttuynai, I don't even have to check it on google because of the way you describe it, especially the smell. I had to riddle all the soil, it took hours of graft. thanks.

I was going to enter houttuynai too. I hate the stuff, which I planted in the front border years ago. I dig/pull it up every year and as motinot says.
Another pest is lemon balm. One clump would be great, but it has come up all over the place.

Calendula. 'Oh, they're nice and bright and will fill up a space while I think about what to plant in the rest of the garden' I trilled while emptying the packet onto the virgin soil. Three years later and they're everywhere! Popping up in the middle of veggie beds; schmoozing up to my Hostas; threatening world domination in the rose bed; hiding in the middle of the lavender; sneaking round the side of the boilerhouse! I've dead-headed, cut back, pulled up by the roots ..... but there they are again - clashing with my red pelargoniums!