I think it may be the Solanum ptycanthum, thanks for the ideas!

It could also be Boltonia asteroides, which incidentally I think it still is :) (not renamed yet.....) Probably not good for a formal flower bed...great in a mass planting or a prairie restoration, in either case. Butterflies love all asters and boltonias though...so it does have worth there too. I've seen migrating monarchs flock to them. This post was edited by dbarron on Wed, Sep 10, 14 at 8:12

It is Lobularia maritima, sweet alyssum. Although not native, it is often included in "wildflower mixes". If you shear it back by half, it will bloom again, if a freeze doesn't get it. In my climate, it is an eager self-sower; one of those once you have it, you can't lose it plants. Here is a link that might be useful: Lobularia maritima, sweet alyssum

Doesn't look like any thyme I know. It appears to have fleshy leaves. There are lots of Lamiaceae family members which are scented, including mint, basil, sage, catmint etc. I was just trying to narrow it down a bit. Can you tell us the dimensions of the leaves?