Most nursery centers carry the bulbs listed in this article. But if you are looking for additional sources, try the following mail-order catalogs. Buy early for the best selection.
Brent & Becky's Bulbs, 7463 Heath Trail, Gloucester, VA 23061; (877) 661-2852 or www.brentandbeckysbulbs.com.
McClure & Zimmerman, Box 368, Friesland, WI 53935; (800) 883-6998 or www.mzbulb.com.
Swan Island Dahlias, Box 700, Canby, OR 97013 (catalog $3); (800) 410-6540 or www.dahlias.com.