The last month of Autumn is an excellent time for gardening. The summer hiatus in the ornamental garden is over but temperatures should stay mild well into May.
There is some time left in the growing season for plants to settle in. It is a better planting time than spring, because the plants can establish themselves and prepare to put on a show as soon as the weather warms after winter.
Summer is a good time to give some attention to water gardens and ponds. You are less likely to suffer from hypothermia and the water can start to get pretty green and algae ridden as temperatures rise. If you don't have fish, you are providing a breeding ground for mosquitoes unless your water is flowing.