Dahlias are late summer bloomers popular for their extravagant blooms, diverse forms, and bright colors. They’re subtropical annuals grown each year from tubers dug up in the fall and overwintered in a cool, dry environment. The sale is sponsored by the Badger State Dahlia Society (badgerdahlia.org). For more information call 608-577-1924.

Olbrich Botanical Gardens

3330 Atwood Ave., Madison

608/246-4550 or www.olbrich.org for details.