These established poppies, their third year, are blooming beautifully. Mid-March in Dallas.
Can you grow poppies in Texas? Yes, indeed. Will they come back? If you keep them watered in drought conditions, yes, they will return.
Will they return from seed? If you gather the seed and plant the seeds in the early, early spring but I have never had a good return from poppies or coreopsis returning without reseeding in the spring. I have had a poor experience with a natural reseeding. There might be a weak showing but very weak.
Poppies in wildflower field.