Plants that became pests

Over the years I've let some plants into my garden that, although seeming like a good idea at the time, turned into thugs intent on taking over the world. Among these have been Allium sphaerocephalon, Gladiolus byzantinus, Stipa arundinacea (Pheasant's Tail grass), Dianella tasmanica and Haloragis erecta.
Anybody else had similar experiences?

 

Don't think I've lived anywhere quite long enough for it to take over
Although, in one of my gardens, I bought a passionflower (the most common one) and that began popping up all over the place (and mainly places I didn't want it )

 

Dont think I've ever introduced a plant to my garden that has become a pest.

But a few years ago I bought a plant that that bitter cress growing in the pot.
Not been able to get rid of the stuff since.

 

None in my own garden (yet), but the two memorable instances in Mum's garden at the family house were:
* The "feral" Buddleia, which grew aggressively large every year no matter how it was pruned. It ended up about 9 feet tall and almost as broad, and got rather in the way of one end of the washing line!
* The Solanum (not 100% sure of the variety) at the other end of the garden, that Mum planted for some fence cover. And oh, DID it cover the fence! In the end, it was spread about 12-15 feet across the whole fence line, was about 6' tall, and the little bench Mum had hoped would sit nicely underneath it was all but devoured. I'm fairly certain she regretted the Solanum.

 

I wish my Dianella would spread, Nigel! Evey year it gets knocked back by frost and has to start all over again.....
Arundo donax variegata, now, there's a thug! And sooo hard to dig out.

 

Whenever I plant owt that I want to keep in check I cut the bottom off a large plant pot ( depending how large the area is I want it to fill ) and then plant it in that and sink it. Seedlings are easy to pull up and either move it dispose of.

For shrubs etc, I think it's more down to human error of trying too squeeze in something too large for the given area available or incorrect pruning etc.

 

Keria japonica was a pain. But we planted Bamboo rather naively and are still paying the price for that act of stupidity!
I inherited a garden with an ornamental cherry and the suckers from that are a pain in the ass. It also had Hemorocallis citrina (yellow Day Lily) which needs to be kept in check constantly.

 

Hi Woo,
I hope you've got your running shoes on

 

Forget me nots, Tiger lillies. What a nasty experience it was trying to get rid of those. Still have some lillies in beside a small tree but am afraid of hurting the tree so I just attack the wannabe lillies that come up outside of the original area.

 

Listen for three taps on the door, that'll be me with your tea

 

I don't regret it yet but I am sure I will from my reading, mile a minute I've put two plants in

 

Wouldn't quite class it a a pest, but ever since I scattered a few seeds of Evening Primrose (Oenothera) around my garden a few years back, it's been mounting a takeover bid. Pops up everywhere and is very competetive.