Bulbs, corms, tubers, and rhizomes fall into the category of geophyte--the fat underground roots or stems that keep the plant alive during cold or drought seasons. A true bulb is a short stem and packed scales that contain nutrition and embryonic leaves and flowers, and is usually covered in a flaky paper-like tunic. Corms are enlarged stems containing a bud on top and covered with dry leaf bases. Tubers are swollen with food reserves and have several "eyes," while rhizomes are horizontal stems from which the stalk and leaves develop. Tender geophytes such as Gladioli and Caladium must be lifted and stored in cold climates. Tulips, Daffodils, Hyacinths, and Crocus, among others, are happier to remain in the ground for the winter, and some species actually require extremely cold temperatures in order to regroup for the following bloom season.


The traditional yearly calendar begins with January, but as we approach the winter holidays, it makes sense to start with this month. Our outdoor bulbs are settling in for the long sleep, but that doesn't mean we can't enjoy some lovely blooms indoors. Forcing bulbs for winter bloom is not a new concept, but one that brings a great deal of pleasure to those who practice it and those who receive the bounty.



Paperwhites (Narcissus tazetta) are native to the Mediterranean region, and are a winter favorite here at home. This highly-fragrant species is easy to force and does not need to be chilled prior to planting. They grow quickly and produce bloom in 3 to 5 weeks. Once the flowers are spent, allow the foliage to wither and the soil to dry out. If you live in a year-round warm climate, plant the bulbs outdoors in a sunny location. Cultivating details.



Amaryllis, from the Greek "to shine", certainly lives up to its name. This magnificent bulb produces bloom that stops most people in mid-step to linger and absorb the beauty. It is native to tropical regions of Central and South America. One of the easiest bulbs to grow indoors, hybrid Amaryllis often grow to almost 2 feet before opening the huge trumpets of bloom. Colors of the rainbow describe this beautiful winter addition to our homes. Choose a large firm bulb with many root buds at the base. Place the bulb into a pot just slightly larger than the bulb, one with room for roots and good drainage. Be sure the neck of the bulb is above the soil-line. Water sparingly for about two weeks when the first sprouts appear, then keep the soil evenly moist. Once the Amaryllis blooms, you can prolong the beauty by removing the anthers (the structures containing pollen). These treasures can be enjoyed year after year by allowing them to go dormant and feed through the summer months. To learn how, read "Amaryllis 101" by Jill M. Nicolaus.



Jewels in the snow. Exactly what we need at winter's apex! One of the first blooms in the year, Galanthus nivalis is the most common of the 14 Snowdrop species, one that blooms for up to 3 weeks. The name derives from Schneetropfen, a German word referring to 16th and 17th century drop earrings. These tiny bulbs flourish in moist semi-shade and sandy soil, producing white flowers. They are good candidates for indoor forcing, grow well in containers, and are perfect for naturalizing a landscape. All Galanthus species are perennial herbaceous plants, native to Europe. Cultivation details. Other "jewels in the snow" include the true blue flowers on Glory of the Snow (Chionodoxa) and butter-yellow Winter Aconite (Eranthus).



Crocus has long been called the harbinger of spring, and with good reason. In late winter, the myriad hues scattered over dull brown earth or dormant grass are enough to make anyone have hope that spring is around the corner. The name comes from the Greek Krocus--the word for saffron, a precious spice produced by this plant. Crocus are delightfully easy to grow, but extremely attractive to voles and mice, so some planning is required before setting out the corms. Crocus naturalizes quickly, so plantings along a path, the base of a wall, or next to a pond will become a wash of color in just a season or two.



No sweeter scent fills the spring air than Hyacinth. Legend has it that the flower was created by Apollo from the spilled blood of his friend, Hyacinthus, whom Apollo had accidentally killed. To grow these bulbs, find a sunny spot with well-drained soil and plant these hardy bulbs for a dazzling display of color. Native to southwestern Asia, southern/central Turkey, and parts of the Middle East, Hyacinths (Hyacinthus orientalis) do not adjust well to the alternate freezing and thawing of the ground in northern climates and, as the years pass, the flowers become smaller and rather straggly. Hyacinths are suitable for indoor forcing, growing in containers, cutting for bouquets, and they naturalize easily.



Everyone loves Daffodils, those cheeky yellow blooms that nod with every breeze, and defy even the deer. Greek mythology is again responsible for naming this flower after a vain youth by the name of Narcissus. Well-drained soil and plenty of sun will bring masses of bloom to your flower beds from late winter into spring. They are easy to force indoors, good for container plantings and cut bouquets, and they naturalize quickly and often with no effort on the gardener's part. Members of the Narcissus genus, Daffodils are native to Europe, North Africa, and Asia, and encompass between 50 and 100 North American species. For more information on growing Daffodils, read "Daffodils and Companions" by Jill M. Nicolaus, and "Daffodils" by Gloria Cole.



In 17th century Holland, the era of Tulip speculation brought a craze for the bulb, the likes of which had never been known. Throughout Europe, they became the ultimate status symbol, and for three years, fortunes were made and lost over this mania. The genus contains about 150 species, with a native range of southern Europe, north Africa, and Asia. They are perennial and one of the last bulbs to be planted in spring--plant them too early and they will begin top growth and be at risk for a hard freeze. Choose rich, friable soil in full sun or partial shade, protected from wind which will destroy the blossoms. Tulips can be forced indoors, used in containers and cut for bouquets, and will naturalize under the right conditions. For more details about using Tulips in your landscape, read Lori Geistlinger's article, "Weeks and Weeks and Weeks of Tulips."

Bearded Iris


Iris germanica bursts upon the June landscape with vibrant colors and breath-taking size, making this rhizome-based plant a favorite in gardens throughout the world. This plant is one of the oldest, with popularity in the Middle Ages as evidenced by the fleur-de-lis which adorns the French royal standard and is the symbol of Florence, Italy. Old-world varieties came to this country with the settlers who used the dried root in herbal medicines. Iris can be frustrating to cultivate, as they demand specific conditions. The rhizomes must be planted shallowly in well-drained soil. Only the roots should be beneath the soil surface. Without enough sun, Iris will not bloom, and if the rhizomes are planted beneath the soil, they will rot. Details on cultivation of Bearded Iris are covered in "Gardening with Bearded Iris" by Jill M. Nicolaus. Dutch Iris grow from true bulbs, and form more delicate blooms. They are suitable for indoor forcing, container plantings, and naturalizing.



One wouldn't think of Onions as ornamental parts of the flower bed, but Allium is one bulb with astonishing landscaping possibilities. These plants often grow to heights of 4-5 feet, with huge globes of bloom which attract hundreds of pollinators. This genus contains about 1,250 species--one of the largest plant genera in the world--and all of them are edible. In many cultures, onion bulbs were believed to repel evil spirits and ward off infection. Plant these bulbs in fertile soil which receives no less than a half day of sun. Keep moist, but not soggy. Allium can be naturalized easily. Cultivation details.



The star of summer is the Lily (Liliaceae) and no wonder--loved the world over, it is always associated with magic and mystery. Greece, Rome, China, and Japan have long built legends around this magnificent plant. The bulbs of true members of the Lily family are never completely dormant, and cannot be lifted and stored during the winter. Plant the bulbs in deep well-drained soil with plenty of sun or light shade. Lilies are considered stemmed leafy herbs, and their pungent scent confirms that designation. Over 100 species exist, but it is important to note that some plants with Lily as part of the name are not true Lilies; e.g., Day Lily (Hemerocallis) or Lily of the Valley (Convallaria majalis).



Gladioli are almost foolproof to grow, well-suited to the gardener who just wants to see the beauty year after year. The word gladiolus means "little sword," and dramatic sprays of flowers in every imaginable color and color combination regally command the garden landscape. Sun and light sandy soil will keep these fast-growing perennials happy; early planting produces bloom in about 120 days, while later plantings yield flowers in 90 days. These tender bulbs must be lifted and stored each winter except in frost-free areas. The corms are not permanent, rather each year new corms grow on top of the old. Ancient Romans planted these beauties over the graves of virgins, but the early 1800's saw the development of modern hybrid cultivars which now number in the hundreds. Bouquets of Glads are magnificent, and the blooms are a big favorite for late summer weddings. For detailed information on growing and enjoying Gladioli, read my article "Gladiolus: Summer's Magnificent Showcase."

Dutch Iris


And so we return to the beginning of the quiet season, a time to put the gardens to bed and think about what we'll do next year. This month is a good time to prepare any of the bulbs you wish to force indoors. In addition to those mentioned in this article, consider Grape Hyacinth (Muscari) or Squill (Scilla). Most bulbs will bloom in 2 to 3 weeks (except Amaryllis), and all but Amaryllis and Paperwhites require several weeks of cold in order to successfully bloom.

Photo Credits:

Allium courtesy of Dave's Garden member Melissa_Ohio

Daffodil by Toni Leland

Paperwhites, Snowdrop, Crocus, Hyacinth, and Tulip all used with permission under GNU Free Distribution License at Wikimedia Commons.

(Editor's Note: This article was originally published o November 6, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)