In regions like the Gulf Coast, the southern half of TX, southern CA and the desert Southwest that suffer very hot summers and yet enjoy mild winters, fall transplanting is absolutely the best time to plant. In fact, the planting season in zones 8-10 extends through winter as well. This will allow the plants to establish their roots before the extreme heat of summer and makes the plants much less vulnerable to drying out too quickly or heat exhaustion.
For these USDA zone 7-10 regions, you can plant any regionally suitable species in fall, with the exception of zone 3 and 4 plants. It's too hot for these cold lovers to do well long term.