08 April 2010

Bulbs, Corms, Tubers and Rhizomes

Bulbs, corms, tubers and rhizomes all have a place in a garden. They are a plant-them-now, enjoy-them- later proposition, unlike the established plants purchased at a garden center. Bulbs, tubers and corms are an energy storage unit that grows roots, leaves, stems and flowers months after they are planted.

A collection of hardy bulbs will give your flower beds, and areas under trees, flower s that will return for several years. Many bulbs will reproduce, giving you the bonus of more plants over the years.

Bulblets form at the base of the mother bulb on gladiolus and along the underground stem on some lilies. Other bulbs make bulbils, or tiny, new bulbs, up toward the top of the flower stems.

Tulips, hyacinth and daffodils grow and bloom from bulbs planted in the fall. Lilies grow from bulbs planted in the spring or the fall.

Tall, stately, Gladiolus grow from spring planted corms; crocus bloom in late winter snow from corms planted in the fall. Corms are actually stems. They multiply by producing small cormels around the base of the mature corm.

Single, double, bearded and water iris grow from rhizomes. So do canna lilies and lily-of-the-valley. Rhizomes are a stem structure whose main stem grows just below the soil surface.

Caladiums grow from tubers, or modified stems. Tuberous begonias and gloxinia develop tuberous stems at the surface of the soil. Dahlias, daylilies and sweet potato vines grow from tuberous roots.
Most gardeners call the whole lot of them bulbs.

To improve your luck with any of these flowers, start with a sunny location. When selecting a planting spot, remember that after the bulbs bloom, the stems must remain in place until they turn yellow. During that period, the leaves of the plant are absorbing energy to feed the bulb for the following year’s flowers.
As the bulb’s leaves are gathering energy for next year, they will stop being attractive so put them where other perennials or annuals will hide them.

Bulbs need a spot with good drainage. If you can situate them on a slope or have a mounded or raised garden bed, either one could give your bulbs a place where water drains away. Another solution is to plant them near trees and shrubs so the tree roots will take up any extra rainwater.


Choose bulbs based on their cold hardiness, bloom time and size. Hardy bulbs such as daffodils and hyacinths will come back next year no matter how cold the winter, so plant those unless you want to replant ever year.

Fall-planted-spring flowering bulbs are sometimes called Dutch bulbs in catalogs.
Summer flowering bulbs tend to be less cold hardy but some bloom longer. Summer bulbs include crinum, caladium, canna, crocosmia, elephant ears, ginger, gloriosa climbing lily, pineapple lily, Peruvian daffodil, tuberose, lycoris and dahlia.
Familiar fall blooming bulbs such as red spider lilies and fall crocus are cold hardy.

Small bulbs are called minor and include crocus, squill, chiondoxa, aconite, anemone and hyacinth. These tiny bulbs have sweet little flowers that provide a carpet under the larger flowers.

Most bulbs like soil pH of 6.0 to 6.9. Add horticultural lime if a soil test indicates the need. Fertilize bulbs at planting time at the bottom of the planting hole. Be sure to fertilize again when they are up and blooming. Some gardeners prefer to add a layer of compost rather than using chemical fertilizers.
You can snip off the flowers when they fade but leave the leaves in place until they fall over.

In addition to local stores, you can find bulbs online. Sources include: Bloomingbulb.com, Easytogrowbulbs.com, Brentandbeckysbulbs.com, Brecks.com, Colorblends.com, Johnscheepers.com, ScrheinersGardens.com, VanEngelen.com, Touchofnature.com and Oldhousegardenbulbs.com.

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