If you have oaks, hunt the acorns till they are gone. Plant your perennial clover, with a cereal grain, that last week in September or the first week in October. Again, this is for where you are in SC and me in Georgia. This is true for your brassica's and annual clovers as well!
Your perennial clover, will come alive, again in September, with the cooler temperatures and hopefully some rain.
One major problem we can have down here, if anything is planted too soon, in the fall, is army worms. They can decimate a cereal grain crop very quickly, so don't get too anxious to plant before the end of September. At that point their "cycle" is over. Besides, September is usually one of our drier months down here.
Also, again hunt the acorns and plant your crops, so that they are young, growing, tender and delicious, when the acorns are gone. Make sense? Take good notes on what you planted, when and where, for next year! It is habit forming!