The trellis is 12 feet tall and 8 feet wide. In that case, while I have never gardened in your climate and I've never grown either of these roses, I suspect these two roses might be worth considering: Climbing Mrs. Herbert Stevens Climbing Lady Hillingdon Both are climbing sports of tea roses (NOT "hybrid tea" roses). I can't easily grow either of these in my climate north of Boston (with really rare exceptions the tea roses like more heat in the summer and winter than I can offer), but in your Houston area climate I won't be surprised to learn there are other rose growers here (perhaps on the "Antique Rose" forum) from the Houston area who are familiar with both of these roses, and can tell you better than I can whether they are climbing roses that do well in your area (as I suspect they might both be). You may well not find either available in a garden center, but you will find them available via mail order from rose specialty nurseries.

I've never gardened in the South, so I have no personal experience with this rose, but if you're open to considering older roses, Climbing Maman Cochet is about 100 years old, but I believe it's still popular in the South (at least among knowledgeable Southern rose enthusiasts), where it grows best. It isn't a modern rose. It's one of the "Tea roses", which were the direct ancestors of today's "Hybrid Teas". Most of the Teas prefer the heat to the cold. They were bred from wild roses native to the Asian sub-tropics (that grew wild in southern China, northern Indochina, and northern India), so they're well adapted to hot humid summers. A 20' trellis is a tall trellis, but I believe this rose is capable of filling such a trellis. By the way, if your idea of "pink" includes the peaches, apricots, & salmons then there are several other Climbing Tea roses for you to consider, too. Oh, and one final thought. As a group the tea roses tend to have flower stems with "weak necks" that are incapable of holding the fully open flower upright. That can be a frustrating fault in a blooming rose bush, but on a 20' climber that's actually an advantage, if you're mostly looking up at the trellis from the ground. If that's the way you'll be looking at the trellis most, then a climbing rose with weak-necked flowers is a climbing rose whose open flowers nod down at you as you look up at them!

I am going to suggest pink Don Juan, it has big, beautiful rich pink blooms that smell wonderful and has been very healthy in my hot and humid Texas climate. I got mine from Chamblees last spring. It bloomed all summer and the blooms stayed vibrant in the heat, it also can handle a little bit of shade as mine stops getting direct sun around 3 pm.

Ramblers are not only usually bigger, but tend to have very pliable, whip like canes that can be easily trained. Many ramblers however are once bloomers. There are some reblooming rambling roses out there tho. There are a many climbing roses that also grow very large and have nice flexible canes, but many can have stiff canes that tequire more work to train. It seems your pergola is a very nice size and you have space for a very large rose or multiple smaller climbers. I would like to add another one for you to consider. Mel‘s Heritage is a very very nice healthy repeat blooming rambler. If you google it and find old threads you can see Lisa’s Mel that is magnificent and Jeri also has a gorgeous one. I have multiple of this rose because it is extremely healthy and low maintenance. It also can be wrapped about anything (just like a rope) 11 feet tall In less than 3 years . Please click to enlarge Another rose that comes to mind is Spirit of freedom. Helen posted a picture of spirit of freedom on her pergola and it is just stunning. It is a beautiful Austin and it gets pretty big.