Both Harris' Sparrows and Juncos are in the sparrow family, but look closely. While a Junco's back is gray, the Harris' Sparrow back is not. It's finely striped like other native sparrows - tan and white. Nor is its entire head dark gray.
In Texas, astoundingly, NOW is the best time of year to plant native prairie grasses. They don't need fertilizer, They need very little water, and grasses require only once-a-year maintenance. They're also mostly free of pests and diseases.
There are several kinds to choose from, such as Little Bluestem, Indian Grass, Gulf Muhly and Windmill Grass. Just be very sure it's a native prairie grass or it could be a problem.