Fall is a good time to think about creating new gardens.
Just remember to get plants into the ground at least six weeks before the ground freezes so they can get their roots established.
If you are planning a shade garden remember that there are different categories of shade:
In a hot climate one can plant many different species in partial shade, especially if the shade occurs in the afternoon. The plants benefit from the sunlight in the morning but get protection from intense afternoon heat.
Roses and other shrubs and perennials that need strong light to bloom well, need at least 6 hours of direct sunshine.
Site each plant in a spot that fits the requirements stated on its tag, as the correct location is crucial to long-term success.