What’s in a bulb

Tue. Mar. 3, 2015

Click below to listen to my Garden Bite radio show:  What’s in a bulb?

What’s in a bulb? Is it really a bulb? Is it a rhizome? Is it a corm? Is it a tuberous root? And what’s the difference? Let’s start with what they have in common. They’re all underground storage units.

All the things they need to sprout and flower are stored in their fleshy structures underneath the soil.

The above photo is a little tough to read due to certain size restrictions for my uploads, however, in the upper left corner is a rhizome, the upper right corner is a runner (think strawberry), smack in the middle is a true bulb, lower left is a tuber and, finally, a corm in the lower right.

Once their leaves are up and at attention, those leaves will manufacture the food that will be sent back down to those fleshy structures underground for storage for next years flowers.


  • Bulb – tulips, daffodils, lilies, amaryllis
  • Rhizome – bearded  iris, cannas, calla lilies
  • Corm – crocus, gladiolas, ginger, bermuda grass
  • Tuber – dahlias, caladiums, begonias, potato

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