There's some perennials you could choose from, such as Scabiosa 'Butterfly Blue' or 'Butterfly Pink', Oxalis, Katie's Dwarf Ruellia, although it spreads a lot. I'm trying to think of those that can handle shade and sun, stay low, and have a long bloom period. I'm sure others will come up with more. My garden is cottage style, or probably better described as hodge podge, but I don't have a single plant as an edger.

Sally

Wilo and I last year got some scabiosa at the end of the season and scraggly for .50. I got them home, deadheaded and they have bloomed ever since all through the winter even.
Another one that bloomed all winter was prairie verbena, also low
The hardy ice plant didn't bloom but stayed green

A cottage garden always looks complete with lavender, and they do very well in the Austin area.

Just make sure that you mix in lava sand with your normal dirt or your lavender will be angry with you and not bloom/grow. They don't like having their feet wet.

Laura Bush petunias or Drummond phlox. Use the link, then do a site search for the phlox.

my favorite is dwarf ornamental peppers. they offer color in the hottest summer sun and take part shade too.

Here is a link that might be useful: Laura Bush petunia

There are a couple good sites to look up some perennials and annuals that do well here in Texas. One is Texas Smartscape - www.txsmartscape.com and the other is linked below - Texas Superstars. You will see the Laura Bush petunia there along with other really good plants for Texas. Just go to the plant search database and select the size of plant, bloom color, etc. you want and it should give you a list of plants.

How about mixing in some burgundy sun coleus with your border - beautiful foliage and nice contrast to other plants. Mexican firebusy would be pretty mixed into the border and its leaves turn a coppery green in the fall. Some other nice plants from the Texas Superstar list are duranta, trailiing lantana, John Fanick or Victoria phlox (maybe a little taller than what you want, but would be beautiful in an English style cottage themed garden), plumbago and/or New Wonder scaevola.

Here is a link that might be useful: Texas Superstar Plants

Pink Skullcap,a TX native reminds me of Snapdragons. It's a very hardy perenial that might work as a subtitute.PJ

Here is a link that might be useful: snap dragon replacement???

Do you want a low plant? Lantana is good and will bloom all year. Salvias are also nice, bat-faced cuphea, winecups, prarie verbena, prostrate rosemary and coreposis. Texas Rock Rose and Turk's Cap will get up to about 24". Texas Gold Columine is nice in shady areas too.

I found dianthus to be very long bloomed here, working as a tender perennial. And then fit nicely in front of my lorepetulum shrubs.

Some varieties of lantana get to be 5' tall, so be careful which you choose. If you go for lantana, be sure to choose one of the trailing varieties. Turk's cap will easily get to be 4' or 5' tall, also, especially in the sun. Both could be planted in the back of the border, but not at the front. Salvia nemerosa, S. superba, S. splendens (an annual) would be among the Salvias to choose, but again, there are hundreds of species and cultivars of Salvia, some of which get very big, so be careful which you choose.

Sally

Hey guys
I am surprised nobody has mentioned Catmint. New to Texas please check this out. Great perennial with gray blue green foliage--dies down in winter only to bounce back at this time of year with beautiful blue soft flowers that you will fall in love with. I will try to post a picture for you when I remember how to do that.
Also Lambs ear --the bigger one Helen Von Stein --is super. For just an annual I like the Zinnia Angustiflora (sp?) which comes in hot orange, pink, or white usually. Thyme is great and sprawls nicely at edges too. Just green though. Snapdragons are a pretty spring temporary plant for pots and little spots in the yard hear and there just for show to me --cannot bear our heat.
Welcome to Texas ! Liz

Liz, I can't believe we didn't either, lol
There are so many plants, my mind swirls most of the time trying to think of them, lol
jolana

Oregano and curly leaf parsley are excellent low plants. The oregano even blooms!
The white and pale purple trailing lantanas mound just a bit, but they may cover everything if you aren't careful.
Not that it matters since they provide easy, beautiful color.
There are lots of trailing verbenas. They have a lovely variety of colors although the plants aren't much to look at when out of bloom.
A mix of plants will give you good coverage and (almost) year round color/texture.

You're right, I did forget that one. My catmint stays pretty much evergreen, but with a bit of a twiggy appearance.

Sally

You might try bearded irises. Before and after blooming they are pretty low growing. They like dry conditions and sun but will bloom even in shade. Plant different selections for a longer bloom season.