Tulips and daffodils are spring favorites of many Iowans. Some individuals, however, are unaware of the wide variety of hardy, spring-flowering bulbs. Little known bulbs, such as snowdrops and Siberian squill, offer exciting opportunities for gardeners. Consider some of the following spring-flowering bulbs when planting this fall.
Ornamental Onions (Allium spp.) are grown for their colorful flower clusters. Flowers are white, yellow, or pink to purple. They bloom from late spring to early summer. Alliums grow best in full sun. The Giant Onion (Allium giganteum) produces pinkish purple flowers in a dense, globe-shaped cluster 4 to 6 inches across. The solitary heads are borne atop a 3- to 4-foot-tall stem. The giant onion usually blooms in late June. Lily Leek (Allium moly) bears yellow flowers in a loose umbel in late spring. Lily leeks grow 8 to 12 inches tall and are best utilized in borders and rock gardens. Blue Globe Onion (Allium caeruleum) produces clear blue flowers on 1- to 2-inch-diameter flower clusters. The flowers are borne atop 1- to 1 1/2-foot-tall stems.
Glory-of-the-Snow (Chionodoxa luciliae) is one of the earliest spring-flowering bulbs. Flowers are star-shaped, bright blue with white centers. Plant glory-of-the-snow in drifts in rock gardens, borders, and edgings. The 6-inch plants prefer sunny sites. 'Alba' and 'Pink Giant' have white and pink flowers, respectively.
Crocuses (Crocus spp.) grow well in either full sun or partial shade. Flower colors include yellow, blue, lavender, and purple. Many blossoms are striped. Plant crocuses in groups of 20 or more of the same color for maximum effect. They are best planted in rock gardens, around trees and shrubs, and among low-growing groundcovers. (Do not plant crocuses in the lawn. The grass will have to be mowed before the plant foliage dies down.) Plants are approximately 3 to 6 inches tall. The Showy Crocus (Crocus speciosus) actually blooms in the fall.
Fritillaries (Fritillaria spp.) are an interesting group of plants with distinctive, bell-shaped flowers. The Crown Imperial (Fritillaria imperialis) is a striking, unusual 2- to 3-foot plant. Large bell-shaped flowers are clustered atop a 1- to 2-foot stalk in mid-spring. The flowers are topped by a tuft of foliage. Flowers are available in shades of yellow, orange, and red. The crown imperial possesses a rather unusual characteristic. Its flowers and bulbs have a musky, skunk-like odor. The crown imperial does best in full sun to partial shade. Once planted, the bulb should not be disturbed. The Guinea-Hen Flower (Fritillaria meleagris) bears nodding, bell-shaped flowers in a distinctive checkered pattern in shades of purple, bronze, gray, and white. The Guinea-hen flower grows 12 to 15 inches tall and does best in full sun to light shade. The Persian Fritillary (Fritillaria persica) produces plum purple, pendant, bell-shaped flowers on 2- to 3-foot-tall flower spikes. Its foliage is grey-green.
Snowdrops (Galanthus nivalis) are among the first flowers of spring. The 6-inch plants produce white, drooping flowers. The solitary flowers are about 1 inch across. Snowdrops do best in partial to full shade. They are ideal for naturalizing under trees and shrubs or at the edge of woodlands. Snowdrops increase rapidly and soon form dense clumps.
Spanish Bluebell (Hyacinthoides hispanica) produces 12 to 15 nodding, bell-shaped flowers on 8- to 12-inch stems. Varieties are available in blue, pink, and white. Plants bloom in late spring. Spanish bluebells perform well in partial to heavy shade.
Hyacinths (Hyacinthus orientalis) are prized for their attractive, highly fragrant flowers. The flaring, out-facing flowers cover 8- to 10-inch, upright spikes. The flowers may be yellow, white, pink, red, purple, or blue. Hyacinths prefer partial to full sun and well-drained soils. They are most effective when massed in beds and borders. Hyacinths can also be forced indoors.
Dwarf Irises are bulbous species that bloom in late winter or early spring. Danford Iris (Iris danfordiae) produces bright yellow flowers with greenish brown blotches. The violet-scented flowers of the Reticulated Iris (Iris reticulata) are blue, purple, or violet with white or yellow blotches on their falls. The blossoms of Harput Irises (Iris histrioides) are light blue to blue-purple. Dwarf irises perform best in well-drained soils in full sun. They are excellent choices for rock gardens and the fronts of borders. Dwarf irises are generally 3 to 6 inches tall. Because of their small size, dwarf irises should be planted in large numbers to create an attractive display.
Spring Snowflake (Leucojum vernum) blooms in early spring. The drooping, bell-shaped flowers are white tipped with green and possess a sweet violet-like fragrance. Plants grow best in partial shade to full sun and are generally 6 to 12 inches tall. Plant masses of spring snowflakes in rock gardens or around trees and shrubs.
Grape Hyacinth (Muscari spp.) produces urn-shaped flowers (which somewhat resemble grapes) on 6- to 9-inch spikes. Flowers are various shades of blue or violet, but there are also white-flowered varieties. The Armenian Grape Hyacinth (Muscari armeniacum) is the most widely planted species because of its vigor and larger flowers. The grape hyacinths prefer full sun and are best utilized for edging beds and in naturalized areas. Grape hyacinths will often send up foliage in the fall, but will not bloom until the following spring.
Lebanon Squill (Puschkinia scilloides) blooms in early spring. Flowers are white to pale blue with dark blue stripes running down the centers of the petals. Lebanon squill performs best when planted in large masses. They multiply rapidly.
Siberian Squill (Scilla sibirica) produces bright blue flowers in early spring on 4- to 6-inch-tall plants. They are easy to grow and prefer partial shade to full sun. Siberian squill are most effective when planted in masses under trees and shrubs, but are also suited for rock gardens and the edge of woodlands. Siberian squill multiplies rapidly. 'Spring Beauty' has slightly larger flower spikes and deep blue flowers.