September is an excellent time to walk around your garden and take stock.
Check to see what plants need to be divided and/or moved. I usually divide plants that I know I could not possibly live without and put new starts of them in different parts of my yard. I like to have the same plant in more than one spot so that if one dies over the winter I have some left in another spot.
Remember to give transplants at least 6 weeks for their roots to get established before a hard freeze.
Now is the time, too, to cut flowers that you want to dry. Globe amaranth (gomphrena), blue annual salvia, and any varieties of hydrangeas can be cut and stripped of their leaves and hung upside down in bunches in the air-conditioned house for later use in winter bouquets.
Also, try to get rid of as many weeds as you can before they scatter seeds that will germinate next spring. Areas of the yard that are all weeds can be covered with a thick layer of newspapers, which is then watered to make it heavy. Then cover the newspapers with a thick layer of mulch so that any plants beneath are smothered all fall and winter.
There is also still time to buy any sale items that you need to fill bare spots in a bed.
If you don't already have a crepe myrtle shrub, do try to plant at least one this fall, and next August when it blooms you will be so glad that you did.
And make some notes to remind yourself what you want to do in the garden next spring.
Of course, plant as many bulbs as you possibly can, choosing some that bloom early and mid and late spring to extend the show.