Mid-September to the first of October is the time to plant your mums and other fall plants.  This is still the growing season until the first hard frost in your geographic area.  Planting now will ensure your fall plants have time to get established and a good chance they will come back again next year.

This is not the time though to plant Spring bulbs because they may start to come up and it's not their time.  Wait until mid to late October to plant Spring bulbs.  However, if you already have bulb plants in the garden and want to move them, it is okay to do that now.  More than likely, they will not restart their growth.

Annuals by this time have pretty much reached their peak.  So, consider clearing them out of the garden.  Some annuals will remain hearty like Impatience and geraniums.

Clean out clay pots and store for the winter.  Leaving them outside in the winter will cause them to crack from the freezing and thawing.

Fertilize all your plants according individual plant requirements.  Contact your local garden center for fertilizing instructions.

Perennials, shrubs and bushes can be left as is until Spring.  That is when you can cut them back for new growth to come through.  Look for new growth before cutting back.