Hello Neil,

In the spring, creeping phlox is pretty and has nice foliage after the flowers.
Currently I have Hardy Geranium in bloom and I like that also.
Sedum is a nice fall groundcover.
Veronica Speedwell is nice but picks up speed quickly when happy and Vinca is another I like.

These are only a few suggestions but I've had good luck with them.

Enjoy!
Kim

Sedum!
I have lots of it growing beside paths and edges. In this image things are yellow and, in a few days from now, another huge patch will be purple. I just love the stuff.
Once established weeds have a tough time.
Not all blooming sedum is "steppable" though.
{{gwi:60170}}

I'm actually in Illinois, Lake in the Hills. Am I correct that we don't need to put mulch if we're putting ground covers? And are the sedum perennials? Where can I buy those? Your garden is really awesome!!!!!!! :D

They are perennial and spread quickly. My sedums are patched with creeping phlox (as a previous post suggested), creeping and wooly thyme and some other thing I can't identify.
I'm not totally happy with the creeping phlox. While it's a blast of colour early in the season I find that, in the sort of full sun heat that the sedums enjoy, it tends to wither away until the next spring.

No mulch around sedums or other groundcover that you want to spread. Many sedums spread by putting down roots where their stems touch the ground. So you need them to contact the soil. (This also means that you will need to weed around the edges of your sedum patch as it expands)
You can buy these just about anywhere. Even the box stores sell them. Get the ones that are showing the densest growth - some sedums have long, lanky branches that don't cover very thickly and you'll end up with weeds.

Check with friends, too, before you spend money on these. I am constantly giving away pieces of my sedums and you barely notice where I've chopped. Considering the ease of managing these plants it's hard to believe people pay money for them - but you have to start somewhere, don't you?

Once planted they'll spread quickly and you can soon divide things up to start new patches. These plants are a breeze to move since they are shallow rooted. Just lift out a piece, make a nice mudpuddle elsewhere and plunk it down.
Best of all, these plants like stinkin' hot sun and can handle droughts.

I'll post another picture of the other side of this bed, with the purple ones, in the next few days. I can't wait till it's blooming! (Can you tell I'm a big fan?? :)

C.