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University of Minnesota Extension

Planting bulbs, tubers and rhizomes

Quick facts

  • The term "bulb" includes corms, tuberous roots, rhizomes and true bulbs.
  • Bulbs are available in a wide variety of sizes, colors and forms.
  • Flowering bulbs are easy to care for and add color and texture to the garden.
Types of bulbs (Left to right): Daffodil (true bulb), tulip (true bulb) and crocus (corm)
Orange and yellow striped tulips
An orange tuberous begonia

Bulbs and bulb-like structures provide energy for plants to grow, bloom and complete their life cycles each year. 

There are several types of bulbs and bulb-like structures:

  • True bulbs are divided into two groups: scaly bulbs like Asiatic lilies (Lilium asiatic) and tunicate bulbs like tulips (Tulipa species).
  • Tubers like dahlias (Dahlia hybrids) have leathery skin and have "eyes" that are buds.
  • Rhizomes such as iris (Iris hybrids) are really underground stems and grow just below or on the soil surface.
  • Corms, such as crocus (Crocus vernus) and gladiolus (Gladiolus hybrids) are a type of compressed stem that contains food and has a bud on top.

Bulbs may be hardy (spring- and early summer-flowering) or tender (summer-flowering).

Hardy bulbs

Hardy bulbs or spring flowering bulbs require a cold period to break their dormancy and begin spring flower development.

  • Plant hardy bulbs in the fall.
  • Hardy bulbs, such as tulips and daffodils, can be left in the ground to flower year after year.
  • Examples of hardy bulbs are tulips, daffodils (Narcissus species and hybrids), iris, crocus and lilies.

Hardy bulbs are quite easy to work with, require minimal care once properly planted, and come up every spring with a wonderful show of color.

Tender bulbs

Tender bulbs, including dahlias, begonias (Begonia tuberosa) and gladiolus, are planted in the spring for summer bloom. Plants with tender bulbs are popular for use in perennial borders, cutting gardens or as bedding plants.

  • Tender bulbs have fleshy bulbs, corms, tubers or roots.
  • They cannot survive cold winter temperatures and must be dug up each fall.
  • Store them for the winter indoors in a cool, dry place.
  • Tender bulbs are planted in the spring after the soil has warmed.


How to plant bulbs, tubers and rhizomes


Hardy bulbs and their care


Tender bulbs and their care


Mary H. Meyer, Extension horticulturist

Reviewed in 2018

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