Chrysanthemum bloom times are dependent on the length of daylight as well as temperature and duration of night, longer nights bring on earlier blooms.
The catch-22 is that the sooner they bloom, the sooner they will also 'bloom out' in which the flowers tend to turn brownish and fall off. To keep your garden full of Mum blooms for the longest amount of time, you should install early, mid, and late season blooming mums!
Just some helpful info from a local gardener,
Coltyn Hehn
