Bulb Basics: Understanding Corms, Rhizomes, and Tubers

Not All "Bulbs" Are True Bulbs

Gardeners often use "bulb" as a catch-all term, but botanically, only lilies are true bulbs. Many popular flowering plants grow from different underground structures:

• Corms: Swollen stem bases with a growth point on top (gladiolus, crocus).
• Tuberous Roots: Fleshy, potato-like roots (dahlias).
• Rhizomes: Horizontal thickened stems growing at or below soil surface (cannas, callas, tuberoses).

Nature's Built-In Pantry

Despite their differences, all these structures function as underground food storage organs, storing energy to fuel the plant from one season to the next. This built-in reserve makes them remarkably forgiving of occasional neglect.

Mail-Order Sources for Quality Bulbs

For the best selection, order early from these reputable suppliers:

• Brent & Becky's Bulbs – 7463 Heath Trail, Gloucester, VA 23061; (877) 661-2852; brentandbeckysbulbs.com
• McClure & Zimmerman – Box 368, Friesland, WI 53935; (800) 883-6998; mzbulb.com
• Swan Island Dahlias – Box 700, Canby, OR 97013; (800) 410-6540; catalog $3