Mints!

[coreopsis]

Don't think you can really kill mint, it always pops up somewhere.

Hmmm,not sure.Had 2 pots with mint,no sign of any growth yet.It's supposed to be a bit warmer next week so I'll have a look if anything sprouts there

[sewer rat]

I have three mints growing at my own place - each is planted in a 5 litre bucket which had the bottom cut out of it and was then sunk into the ground - these contain the mints and has been successful in stopping it spreading for 3 going on 4 years.