What can I put in these planters that doesn't need much looking after?

[Caz10]

I bought 2 planters something like this last weekend, one is about waist height the other slightly lower. I'd like to put them out at the front of my house, with something in them that even I can't kill...any suggestions? Thank you!

lavender

I actually have a lavender plant I thought about moving in, but it is quite big - does it not spread? Or will it just be contained by the size of the pot? (sorry, novice here). Similarly I have a hebe (sp?) that I could put in, but again it's quite big?

I have a big lavender that is ancient but keeps going and I think is restricted by size of pot - otherwise it'd have taken over the garden...don't know about hebe

2 or 3 Cosmos plants in each pot - will give you clouds of flowers all summer. Lovely and look great as a statement out the front. They are annuals though.

We had a hebe that did very well in a container, and I can attest that they are VERY hard to kill.

one of those spiky purple plants. mine is massive i only got it for £1.99 when it was tiny

oooh what is the purple spiky one that sounds nice!

will look for cosmos, thank you.

this is my 1st venture into the gardening forum, and I am so impressed that the side-bar advert changes appropriately!

I do like my hebe - have never managed to kill it either - and think the bright green would look nice against the slate grey, iyswim

i don't know a something it's like a mauve yucca