March is pretty much the last call for heavy pruning on flowering cherries. These need their pruning done in summer to reduce disease. While you are about it, you can prune plums and other deciduous fruit trees straight after harvest. This encourages them to set more fruiting spurs for next year, rather than too much leafy growth.
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.