Question
When can i plant (south alabama) what kind of mix where to purchasej

Answer
i'm in southern NJ. as long as the ground & air temps are above 50 degrees, and your local garden center still has some seed in stock you should be able to do it.  you will need to till the area 1st.  they are perennial plants and should come back every year.  the key this time of the year is to make sure the area stays moist so the seed will germinate quickly and not die.
get to a local garden center/nursery and quiz them on planting wild flowers this time of the year in your area.
buy your products from them and they should be more than happy to help you.  
good luck
rick
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