When do dahlias bloom?

Dahlias grown in colder climates bloom from the middle to the end of the growing season, which is mid-summer, until the first hard frost. Dahlia flowers continuously in temperate climates like its native Mexico, where it is the national flower.

In climates with temperatures below 20 degrees Fahrenheit, dahlia tubers are dug up when the plant is dormant. They are stored in a cellar or garage for the winter and planted after the threat of frost is gone and the soil is warm.

The Aztecs grew dahlia tubers as a food crop and used the long, hollow stems of Dahlia imperalis to transport water.