Chrysanthemums are an iconic autumn flower. Pots of blooming mums are sold at every garden center, supermarket, and roadside stand by the end of August. Their rich colors of garnet, purple, bronze and brilliant yellow or pale cream have tempted me many times. I buy them, but am mildly disappointed that even after I put them in the ground they maintain a strict military stance, never softening into a graceful slouch. Neither have I been able to overwinter…