I have a Pakistani mulberry, which is a tall commercial mulberry tree, and a couple of native mulberry trees. There are two mulberry trees native to Texas, the Texas Mulberry (rough, sandpaper leaves on both sides of leaf) and the Red Mulberry (rough top surface of leaf, fuzzy underside). The Texas Mulberry grows in the western 2/3rds of Texas and the Red Mulberry grows in the eastern half of the state. If you can't find a native in a nursery near you, try contacting the Lady Bird Johnson Wildlife Center in Austin.
Silkworms go through a lot of leaves, even when newly hatched.