Can't answer for Houston, but I use them here in the Dallas area and they thrive! They love the heat, and I haven't seen humidity present a problem...so???

I really don't see them used a lot either. Maybe it's just an underutilized, not well known plant. The only issue I have had is the bunnies eating them...but my liquid fence put a stop to that!

Thanks acalta. Do they come back year afte year in your garden?

Sure do. Any they grow very quickly. I actually just bought a new one to put where I had to rip out a dead lavender.

Another question for you acalta. During winter, do they completely die down or do they stay green. And what kind do you grow. Thanks.

Yes they do die completely down. They started coming back about a week and a half ago. I grow tickseed nana.

the Cruzin series of coreopsis is supposed to do well in Houston. Not easy to find, but I know Enchanted Gardens iin Richmond TX carries it. perhaps Arbor Gate and the ones in The Heigihts have them too. Call around

I bought 'Nana' at a Dallas area Lowes last week and generic coreopsis in previous years. Search your local store on their website to find out what varieties they MIGHT have in stock. Can also occasionally find them on their clearance/distressed sales racks.

they do great down here. You don`t see them a lot in landscaping because for the most part they are considered a wild flower, great blooms in spring then seeds then die back in our heat depending on the variety. Landscapers all like to use the same kind of stuff if you have noticed, raised in bulk, sold cheap and for the most part ugly.
Houston garden center always has a bunch of different ones, you can sow seeds in the fall.
I use them extensively in the garden and have them in my community garden plot. Some tend to get large, tall and straggly, not what landscapers want.
Tally Ho!