Answer: The chrysanthemums you find in garden centers are perennial; florist mums (typically found at the grocery store in the fall) are annual, because they are unable to develop enough runners to overwinter.
It's best to plant garden mums in the spring so that they have all summer and fall to develop extensive root systems before winter sets in. You can plant in the fall, but you'll want to find good sized plants with well developed root systems. Mums prefer a rich, moist, well-drained site. Provide them with plenty of water throughout the summer; flowering is affected by lack of water. These plants do not tolerate wet soils, especially in winter, so be sure the planting site drains well. Plant in full sun. In the spring, when new shoots appear, regularly cut or pinch them back to promote branching. Pinch about every 4 weeks, up to the beginning of July.
Enjoy your mums!
Q&A Library Searching Tips