Tubers, Corms, Rhizomes, and Bulbs... What's the Difference?

Over time, the term "bulb" in gardening terminology has come to describe any type of root form that is planted in the ground to produce a plant. However, only a few of these plants can truly be defined as bulbs. There are four different types of reproductive structures, including Tubers, Corms, Rhizomes, and Bulbs. We'll explain exactly what the true difference is between these four terms!

Dahlia TuberDahlia Tuber
Dahlia Tuber
Saffron CrocusSaffron Crocus
Saffron Crocus Corms
bearded iris rhizomebearded iris rhizome
Bearded Iris Rhizome
Tulip BulbsTulip Bulbs
Tulip Bulbs

Tuber

Tubers are formed from a stem or root. They store nutrients that allow the plant to grow the following season. Shoots grow upwards from many different places on the tuber. Examples of tubers are Dahlias, Begonias, Anemones and Potatoes. 

Corm

Corms are actually enlarged underground stems that store nutrients, surrounded by papery outer layers. After stems sprout from the corm, buds form on top of the stem. Corms at their center are solid tissue, whereas Bulbs are immature layers of leaves. At the end of the growing season, a new corm typically grows on the base of the spent one, and plants regrow from new corms each season. Examples of corms are Gladiolus and Crocus.

Rhizome

Rhizomes are stem-like structures that grow horizontally across the ground, forming roots from the bottom while sending shoots upward. Buds form at different parts along the structure, not necessarily at the top. Rhizomes store nutrients for newly growing plants. Examples of rhizomes are Bearded IrisCanna Lilies, and Calla Lilies.

Bulb

A bulb is comprised of a plant's stem and leaves. The bottom of the bulb is a compacted stem, and roots grow from this part of the bulb. Layers of nutrient-filled leaves sit at the bottom of the bulb and surround a bud that eventually becomes the flower. Examples of bulbs are Tulips, Lilies, and Daffodils.

 

Whether your plants are growing from a Tuber, Corm, Rhizome, or Bulb, all of these plant structures are sure to produce a spectacular show in the spring and summer months. Happy Gardening!

If you have questions about how to grow these plants, visit The Tool Shed, our source for helpful planting guides! Or, contact us to speak to our team for friendly garden advice.

Shop Flower Bulbs (and Corms, Rhizomes, and Tubers!)

  1. Colorful Cutting Garden Collection

    Our Colorful Cutting Garden Collection provides gorgeous flowers for bouquets or vases. Create different arrangements based on when flowers are in bloom. Enjoy them for yourself, or ...

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    Colorful Cutting Garden Collection Colorful Cutting Garden Collection
    $79.98 Sale $39.99
    Per Collection of 32
    Our Colorful Cutting Garden Collection provides gorgeous flowers for bouquets or vases. Create different arrangements based on when flowers are in bloom. Enjoy them for yourself, or delight your neighbors, friends, and family. If you crave fragrance look no further than 'Double White' Freesia with creamy-white, double-petals. The color palette of 'Nashville' Calla Lily's pale buttermilk blooms overtaken by magenta-purple, helps blend hues of 'Otto's Thrill' Dinner Plate Dahlias 8-10" cotton candy pink flowers and 'Blue Bayou'® Anemone Dahlias lavender-blue petals. This collection is easy to grow in full sun and produces blooms from late spring until frost. Collection of 32 bulbs.
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  2. Apricot Impression Darwin Tulip, Tulipa Apricot Impression

    Graduated pink and tangerine blooms top a stately 22-inch stem in 'Apricot Impression' Darwin Tulip, creating a glowing effect in beds and borders. These large, softly radiant blooms...

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    Apricot Impression Darwin Tulip Apricot Impression Darwin Tulip Tulipa Apricot Impression
    As low as $9.99 Sale $7.49
    Per Bag of 10
    Graduated pink and tangerine blooms top a stately 22-inch stem in 'Apricot Impression' Darwin Tulip, creating a glowing effect in beds and borders. These large, softly radiant blooms are held on slender but strong stems in mid-spring. Like many Darwin tulips, 'Apricot Impression' has a long-lasting bloom season, allowing the gardener to get the most from the planting, and making a great choice for the cut flower garden! (Tulipa)
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  3. Peppermint Stick Tulip, Tulipa clusiana Peppermint Stick

    Treasured for its dual-toned blooms and a tendency to return year after year, 'Peppermint Stick' Tulip is a low-growing species tulip with plenty of punch in a petite frame. In mid-s...

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    Peppermint Stick Tulip Peppermint Stick Tulip Tulipa clusiana Peppermint Stick
    As low as $13.32 Sale $9.99
    Per Bag of 15
    Treasured for its dual-toned blooms and a tendency to return year after year, 'Peppermint Stick' Tulip is a low-growing species tulip with plenty of punch in a petite frame. In mid-spring, the delicately pointed blooms reveal pure white centers flanked by outer petals with a red-pink reverse. 'Peppermint Stick' is an RHS Award of Garden Merit winner and naturalizes in a well-drained, sunny spot. (Tulipa clusiana)
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  4. Purple Saffron Crocus Bulbs, Crocus sativus, Saffron Crocus

    Saffron is worth its weight in gold, so it pays to grow your own! These beautiful purple crocus flower in fall and offer you pure, prized edible saffron on each flower's stigmas. Ea...

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    Saffron Crocus Saffron Crocus Crocus sativus
    As low as $10.65 Sale $7.99
    Per Bag of 15
    Saffron is worth its weight in gold, so it pays to grow your own! These beautiful purple crocus flower in fall and offer you pure, prized edible saffron on each flower's stigmas. Easy to grow and exceptional in containers. (Crocus sativus)
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