Dianthus is nice for edging. You can also use annuals like petunias. They're cheap in the six-packs.

Here, candytuft is an evergreen, not sure about your zone. And don't forget about creeping sedums. Many bloom and some are extremely cold hardy.

Ajuga and mazus are good groundcover perennials too.

I was given annual candytuft seeds. I didn't even know it was a perennial, and it's hardy to zone 3. That sounds like a great one to consider.

I had heard of bugleweed before but was concerned about its invasiveness. If it would spread and grow between the rocks that would be very welcome, but I don't want it taking over the perennial bed. I'll check around on its invasiveness in my area. And, a note on invasiveness, I had to deal with some serious invaders with my weeding last year. There was artemisia everywhere, but it was shallow-rooted and once pulled was gone for good. Piece of weeding cake. Then there's mint and wild strawberries. I'll never be rid of those. Trying to figure out if I can get the strawberries to fruit so at least their invasiveness will do some good. If bugleweed is easily pulled like the artemisia was then I won't mind. I just don't want deep hidden roots that I'll never get rid of.

Thanks so much for your prompt reply! (Too bad butterfly bush wouldn't work for edging-got plenty of those, right ;-) )

LOL. I bet your do.

Wild strawberries are all through my yard. They do fruit, but only tiny things that the birds gobble before they even ripen. Nothing to write home about.

I 2nd the candytuft
Phlox
Veronica: Georgia Blue
Perennial Dianthuses: Bath's Pink, Firewitch, itsaul white and many more
chives (for a little spike out in front!)
Coreopsis: Sweet Dreams and nana (mouse ears)
Heuchera
Tiarella
Woods asters
dwarf hardy grasses
miniature dwarf irises: I have the cutest pink called Betsy Boo blooming now!
Dwarf siberian iris (usually white or blue)
lambs ears

A great place to do a little research is on the Bluestone website. They have a nice variety and list the hardiness zones!

I had the same experienced the same thing when I used mulch over weedcloth. It was on an inclined area so naturally when rain came, the mulch washed off into the sidewalk. I finally had to remove the mulch.

Anyway, great edging materials for our zone:

evergreens: use boxwood every few feet. In between add the flowering perennials.

Lavenders
coreopsis (dies back into the ground each winter)
lady's mantle (reseeds though- easily controlled)
lamb's ears - although they do spread but are easily controlled
siberian iris
regular iris
heucheras
coral bells
sages

grasses:
blue fescu
fountain grasses

I have pink creeping phlox planted in the front of my flowerbeds. My candytuft and alyssum didn't make it in the coffee cups that I used to WS those seeds, so I am going to have to buy some starter plants. I know the pink creeping phlox is only going to be blooming for a short while. What would you suggest to go behind the phlox. I can fill in with petunias or verbenas between the creephing phlox plants. Don't you think a blue/purple upright plant, maybe spiky behind the creeping phlox? What about May night salvia or something like campunulas? I'm going for the cool colors in a cottage garden theme. I've got some WS purple shades of zinnias planted. What about some short versions of garden phlox, or daisies or coneflower but those are usually taller.

Arabis caucasica 8" plant 14 inches apart zone 4-8 Sweetly scented, available in white (snowcap) or deep pink (red sensation).

Artemesia stellerianna (silver brocade) 6" plant 20 inches apart zone 3-8

Lamium (sliver beacon/lavendar, nancy/white, pewter/pink) The leaves are varigated pale green/silver. It is a great ground cover that gets little blooms on it. It spreads and fills in nicely (easy to pull), I have it along my sidewalk in a mulched bed, full sun or full shade.

Armeria pseudarmeria Ballerina or dwarf sea thrift (bloodstone/deep pink, dusseldorf pride/red 8-10" plant 12 inches apart zone 3-9

Campanula Samantha deep purple 6" plant 15 inches apart zone 5-9

These are just a few possibilities. They are from the Bluestone Perennials catalog which you can order from their website. The plants usually come in 4-6 inch pots but they are priced 3/$one money, in most cases. Always very healthy in my experience. There are dozens more that would work for you in the catalog. Or just order online.

MeMo

My mom uses crocus as an edger along her sidewalk. They're very pretty in the spring and then she has alyssum that reseeds and comes up to fill in as the crocus dies back.

She's in zone 5 and once she plants the white alyssum, it comes back every year. It's usually much fuller when it reseeds, than when she buys the annual packs to set out. I'm going to try the same thing with the lavender alyssum this summer, in the front of my perennial beds :)

I have several different low growing plants along the edges of my flowerbeds - I'm not a great fan of that "long line of all the same" that can result when you choose just one. That's just me, though. I've seen pretty spectacular photos of beds edged in nothing but lambs ear.

I use candytuft and creeping phlox as others have mentioned. I also have soapwort and golden alyssum that I just love. There are a few clumps of German catchfly and dianthus (the one that makes a mat of blue green with bright pink flowers above - I can't think of the name of it just now). All of these are very hardy and pest free and I love the variety as well as the way they relate when repeated in one section of the border and another.

Not sure how hardy Dianthus is in your area but I planted it for the first time last summer and it's already up and ready to bloom. It's really spread out and doing great.

It bloomed for me all summer long, and it's in a flower bed that had a solid sheet of ice on it for a couple of weeks.

These are plentiful and great suggestions. They will be a HUGE help to me! I can't thank you enough.

Off to do some plant research!