Flower or Weed

I've planted a good few new perennials in recent years but suspect that this is an invader. Can anyone help me identify this plant please?

 

It looks like a wallflower to me.

 

If it had a flower on top I'd say it was a crown imperial, but obviously not.

 

Do they grow 'blind'? It certainly looks like F. imperialis foliage.

 

Most of mine do.

 

Hmm! Thinking.

Don't think Fritillaria imperialis leaves are a good match.

 

Looks like a Alstroemeria to me

 

They remind me of florist Alstroemeria leaves but doing a search on www the leaves look much fatter.
If correct they will flower later in the summer.
I have never grown them and have no pics of the leaves..just the flowers.

 

Pictures of my alstroemeria indian summer leaves

 

Thank you for all your responses, I think that Alstroemeria could be the answer as I planted a small number of bulbs a couple of years ago. I'm surprised how thuggish it seems with the spread this year, A question of wait until Alstroemeria flowering time and see, I think!

 

Ah well, if thuggish .....then that fits Alstroemeria perfectly!
keep us posted.