Citrus Trees are Technically not cold hardy in Central Texas. This means sometime In a 20 year period they are likely to experience a hard, killing freeze.  We do have a fair amount of customers(friends really) who have planted some varieties in the ground, outside with really good luck.(mostly Miho Satsuma, Owari Satsuma & Meyers Lemon).  We do Still strongly suggest you plant yours in a 20” clay pot, using our really great potting soil.