Hi Molly..I am just North of you on Lake Conroe in Willis..I find the pruning group 3's are the best to plant with Roses...the Viticella's are Hard pruned each late winter/early Spring and after their bloom period to induce another one as they bloom on current years vines/new vines...In our long extended growing season it's not impossible to get 3-4 bloom periods from them using the hard prune method after the heavy bloom period...You can go to COTW and click on Search and put the color of the Tepal/flower petals and then where it says pruning group click on the menu and put in Hard Prune 3
this will give you tons of clematis to choose from.. I really like buying Clematis from Dan over at http://www.brushwood.com and Chad over at http://www.Gardencrossings.com they have some beautiful well rooted clematis..remember in our Hot climate they need to have their roots stay moist..very important to plant them 2-4 inches deeper than the pots they come in with a couple handfuls of bonemeal in the planting hole...I like to plant mine at a slight 45 degree angle in the hole directed towards the rose or whatever you want it to climb on...I find mine do best where they get 6 hours morning sun and shaded from the hot afternoon sun..but if you stay ontop of keeping them watered they can do well with more..Hope this helps..if you need color suggestions please ask...some of the Viticellas/pruning group 3's that I grow are:
Hagley's Hybrid (lavender-pink)
Comtesse de Bouchard (pink)
John Huxtable (white)
Avant-Garde (gorgeous red and pinkish)
Jackmanii (Purple)
Royal Velours (Purplish-red)
Solina (light lavenderish-purple)
Etoile Violette (purple)
Purpea plens Elegans (dark dusty purple)
Polish Spirit (dark Purple)
Huldine (white)
Venosa Violacea..I love this one so much I have 3 (purple and white)
Jeanne

Here is a link that might be useful: COTW SEARCH

Thank you so very much Jeanne. The COTW website is awesome. It appears the brushwood website has nothing to do with clematis (typo error?), but the gardencrossing is great and I plan to order a couple of clematis from them.
Thanks again for the great info.
Molly

Molly..sorry ...Dan has his site listed as gardenvines.com...I have put the link for you..he is a great guy too!!...Jeanne

Here is a link that might be useful: Dan at Gardenvines