The temperatures are becoming cooler, which is your signal that it is now a great time to plant any new trees. Just make sure to dig a hole 3 times the size of the root ball.
Cool weather lawns like fescue can now be fertilized and warm weather lawns like Bermuda can now be winterized.
Peony plants can now be planted.
Begin to think about where you will plant your bulbs for the Spring, but do not plant them until much cooler weather, possibly in October.
You can now overseed warm season lawns with cool season perennial rye grass or annual rye grass. This will provide a green lawn in the winter months.
There is more to fall color than just Mums! You might also want to consider planting aster, ironweed, sedum, Confederate rose, and goldenrod.
Cool season ornamental grasses can now be planted.
Consider starting a compost pile for your fallen leaves.