Welcome Shllyah!
Are you thinking of veggies or flowers?

Most deciduous shrubs are best planted now as they will make some root growth before winter. They grow away better in Spring too. Also, some herbaceous perennials can be planted now.

Moon_grower has an excellent blog on what edibles to plant in September, and she should soon have one for October, too. The September one is at:

http://www.growsonyou.com/moon_grower/blog/11676-what-to-do-and-grow-in-your-veg-garden-in-september