I have had a lot of problems trying to have bluebonnets and paintbrushes in my yard till this year. Now I know that they will not grow on my clay soil unless I add sand and build up the level of the soil where they are planted. The rain must be able to both run off after a rain, and it must be able to penetrate the soil while it is raining. Beyond that, about all I have to do is protect them from the mower.
If you need a few seed, send me a message, and I will be able to send you a few in about a month.