Chrysanthemums are the quintessential autumn flowers in this hemisphere, but the best time to plant them is now, in the spring. Buy "baby" plants but allow them plenty of room to grow and expand, as they will reach maturity and bloom their first year.
Mums need good drainage, and this is especially so in the winter so they don't rot. Pinch them back regularly this summer so that they become full and bushy by fall. Stop pinching by the 4 th of July so that they have plenty of time to set their buds.
There are many different types of chrysanthemum blooms:
It is best not to try to overwinter the full size mum plants that are purchased in full bloom in the fall. While occasionally one can be lucky with these and have them persist in the garden, more frequently they do not have enough time to get their roots established before the cold weather. It is more cost efficient to buy small mum plants now, and by fall you will have many lovely flowers on well-established plants that will last in your garden for years.