Poliomintha longiflora aka "Mexican Oregano" likes full sun and blooms most
of the summer. Hummingbirds and butterflies love the blooms. It's usually
evergreen through mild Austin winters. A recommended xeric plant:

http://www.nativesoftexas.com/moregano.html

While it can be used as an herb in cooking, this is not the same plant as
the culinary Mexican Oregano (Lippia graveolens) or the culinary
Mediterranean Oregano:

http://www.herbsociety-stu.org/Oregano.htm

jjhnsn

I'm not a Master Gardener, but I sleep with one.