Seeds & seeding
In the How To article on meadow gardening, it recommends that a good chunk of your garden (50%-80%) should be native grasses. The kind mentioned in that article are typically warm season grasses. In what order should I plant - wildflowers in the fall and then grasses in the spring; grasses in the spring and then wildflowers in the fall; or both of them, either in fall or spring?
The Texas Department of Transportation has a good information sheet on seeding wildflowers on their website. They say "By and large, most Texas wildflowers should be planted in late summer or early fall, especially bluebonnets."
Also, the Wildflowers in Bloom website maintained by Dan Lineberger and Jerry Parsons has a lot of good tips about growing wildflowers that they have obtained from Wildseed Farms.
For information about seeding native grasses, take a look at the Native Prairies Association of Texas website where they have a page from their Tallgrass Restoration Manual. While most of their information is for large scale restoration, they do discuss the four prairie grasses and explain how to make seedballs - a fun way to seed.
They say ... Once the seedballs are dry, throw out by hand at the restoration site. The clay will protect the precious seed until rain arrives, then the seedball will melt and the seed will germinate. The clay will also keep the seed in place if the rain turns into a ‘gully-washer’.
So the timing of sowing your grasses is not as critical as with the wildflowers.