Looking beyond bulb basics
October 10, 2007
Fall is bulb-planting time.
Most people are familiar with the basic bulbs, such as daffodils and tulips. But, what about some of the plants commonly called bulbs that are actually corms, rhizomes, tubers or tuberous roots? All of these terms refer to the specialized underground structures that are storage organs for many of our spring-blooming plants. Through the growing season, they gather up nutrients, building up reserves that will allow the plants to survive through dormancy and burst into bloom at the appropriate time.
A true bulb is, in essence, a baby plant surrounded by scales that are modified leaves held together at the base of the bulb. The papery outer layer is called a tunic, which some bulbs have and others, such as lilies, do not. The tunic protects the bulb from drying out. Tulips, daffodils, hyacinths and narcissi are true bulbs.
Some other bulbs include the scilla or bluebell and grape hyacinth. Both show their heads early, foretelling spring. Scilla are bell-shaped or star-like, and range in color from white to deep purple. Grape hyacinths spread very easily, adding a lovely touch of blue throughout a garden bed.
A corm is similar to a bulb, but it doesn’t have scales. Rather, it is a solid, swollen underground stem. It also may have a tunic. Crocuses and freesias are corms. An interesting twist is that there are spring- and fall-blooming crocuses.
A tuber is also a swollen underground stem, but it differs slightly from a corm in that its roots grow from all over, rather than from the bottom. Cyclamen and begonia are commonly grown summer tubers, but not hardy for fall planting in our area. Anemones and winter aconite are also tubers and most are suitable for fall planting.
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A rhizome is actually a stem that grows underground or partially aboveground. Irises are the most common flowering rhizomes in our climate.
Finally, there are tuberous roots. These are true roots, rather than modified stems. They grow in a cluster. Dahlias are one example, and need to be brought inside for winter in this area.
Within all these classes of spring flowers are multiple varieties of each. An infinite palette of colors, textures, growth patterns, fragrances and styles are possible. Explore the wonderful options available now for fall planting, and express yourself by creating a spectacular spring display.
For more information, e-mail firstname.lastname@example.org or call me at 887-2252. You can “Ask a Master Gardener” by e-mailing email@example.com or call your local University of Nevada Cooperative Extension office. Check out many useful horticulture publications at http://www.unce.unr.edu.
• JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension.