Many of the most colorful and exotic flowers in our gardens come from specialized tissue under the surface of the soil known as bulbs. Botanically, these may be "true bulbs" (daffodils) or "corms" (crocus). All are known as "bulbs" to the gardener and so are discussed together.

The bulbs provide a class of plants that are indispensable to season-long bloom in the garden. The bulbous plants provide the earliest bloom from the crocus, snowdrop, winter aconite, and netted iris to the last flowers in the fall, the colchicum and autumn crocus.

None of the bulbs are hard to grow if you follow a few basic principles. The starting place for success is a good bulb. Buy bulbs only from a reliable dealer. Beware of "bargain bulbs." These bulbs may be culls-damaged or undersized. You get what you pay for. Secondly, plant your bulbs in a sunny, well drained location. To determine if the proposed area has good drainage, consider these questions:

• Do perennials die out over the winter there?
• Does water stand there very long (over an hour) after a rain?

If either answer is yes, then look elsewhere for planting space for bulbs. Sun is not absolutely essential, but bulbs in full sun will bloom earlier and last longer. Any bulbs doing best in shade will be noted in the descriptive list. Do not plant your bulbs in a lawn area needing to be mowed before the bulbs have matured. The foliage of the bulb should not be cut off before it dies down. Most bulbs look best when planted in large clumps for bright showings at blooming time.

Once you have decided on a location, prepare the soil well. Most bulbs do best when left in the same location as long as possible. If possible, spade the area to several inches below the depth of the bulb. Bone meal and wood ashes are the usual fertilizers and are adequate. Use three to four pounds of each per 100 square feet of soil. If no bone meal or wood ashes are available, a general garden fertilizer will be just as satisfactory. Use two to three pounds of a 5-10-10 fertilizer per 100 square feet.

The depth of the planting will vary with the bulb you are planting. A general guide is two to three times the length or width of the bulbs. If in doubt, go deeper. Again, any variation will be noted in the descriptive list. Plant the bulbs slightly further apart than they are deep. For example, if you plant a tulip six inches deep, plant them seven to eight inches apart.

When digging a hole for the bulb, be certain the hole has a flat bottom. Do not make a V-shaped trough that might leave the bulb with air spaces under it. Put your fertilizer in the bottom of the hole first and stir it in well.

After the ground is frozen in the fall, mulch your bulbs with evergreen boughs or coarse straw. This is to prevent freezing, thawing, and premature growth in the spring. Fertilize the bulbs each fall with an application of fertilizer at one half the rate suggested for planting.

Never cut off the foliage of the bulbs while they are still green. These green leaves are building up food for next year's flowers. If the bulbs become crowded and do not bloom, it is time to divide them. Dig them as soon as the foliage turns brown. If possible, replant them the same day. If that is not possible, they should be cured or left to dry in a warm (not hot) well ventilated area. Then store them in a cool area with good ventilation.

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Descriptive List of Hardy Bulbs

Camassia - Creamy white to rich purple flowers on tall spikes. Most common forms are blue. Range in size from 1 1/2 to 3 feet. One of the few bulbs preferring a moist location and shade. Excellent in shady border or rock garden. Plant 4-5 inches deep, 9 inches apart.

Chionodoxa (Glory of the Snow) - A dwarf plant for naturalized planting. Pale blue with white center most common; white and pink also available. Blooms in March or April.

Colchicum - A plant which has foliage in the spring and flowers in the fall. The flowers look much like that of a crocus. Colors are white through lavender and orchid. The corms are large but should only be planted 3-4 inches deep. Flowers will be 4-6 inches high. Do not cut off the foliage in the spring, even though there are no flowers.

Crocus - Best used in naturalizing or against the background of shrubbery. Both spring and autumn flowering species are available. Colors range from white through yellow to lilac, purple, and blue. Multiplies rapidly. Plant fall-blooming species in July or August; spring-blooming species in October.

Eranthis (Winter Aconite) - One of the earliest flowering bulbs, blooming with the snowdrops. Winter aconite flowers seem to rest on a green collar of foliage. The plant grows 4-5 inches high. Plant these bulbs in late August or early September about three inches deep and four inches apart.

Fritillaria (Crown Imperial) - A very hardy but little-known bulb that grows in sun or partial shade. The flowers are drooping, bell shaped, and hang down in a cluster under a crown of dark green lily-like foliage. The stem is 2-4 feet tall. Plant the bulbs 4-5 inches deep in a sheltered location. Do not disturb them if possible.

Galanthus (Snowdrop) - A small, white, nodding flower with a heart-shaped decoration of green. Growing only a few inches high, they are most effective in drifts. Plant them three inches deep and three inches apart in September.

Hyacinthus (Hyacinth) - A familiar spike of many flowers, hyacinths come in many colors. Try them informally for something different.

Iris - Two bulb forms are dependably hardy in Pennsylvania. Dutch forms are well known as the florist's iris. They come in whites, yellows, and lilacs, and grow on a two-foot stem. Give full sun and some winter shelter. Netted iris (Iris reticulata) is very early, blooming in early March. It is a six-inch purple flower that has a delightful fragrance. Plant three inches deep and three inches apart.

Leucojum (Snowflake) - Similar to the snowdrop but taller, often 8-15 inches. It blooms in March through June depending on the species.

Lycoris (Hardy Amaryllis) - A "magic" flower that produces foliage in the spring which dies down shortly thereafter. In August, apparently from nowhere, appears a tall stalk of pink, amaryllis-like flowers.

Muscari (Grape Hyacinth) - A small flower with a spike of tiny round flowers. Colors are white, pink, and blue. Plant in large groups in the fall.

Narcissus (Daffodil) - Daffodils come in all sizes and shapes. Don't overlook the various forms when selecting.

Ornithogalum (Star of Bethlehem) - White starry flowers 6-8 inches high. Tolerates sun or shade. Naturalizes well.

Puschkinia (Striped Squill) - A spike of white flowers with blue stripes. Grows 4-6 inches high, and blooms in early April.

Scilla hispanica (Wood Hyacinth) - A tall spike of nodding flowers in white, pink, or blue. They naturalize well or look nice planted in front of evergreens. Height is one to two feet. Blooms in late May.

Scilla siberica (Siberian Squill) - A low growing, bright blue flower that blooms in early April. The variety 'Spring Beauty' has the most intense color. Plant this in large groups with other spring flowers or in front of evergreens.

Tulipa (Tulips) - A large group ranging from the common singles of any color through doubles, parrots, and into the species such as the little Turkish tulips only six inches high. The species are long-lasting bulbs, while the usual forms should be replaced every third year.

Southeastern Pennsylvania gardeners have a slightly larger selection of bulbs. In addition to the above are Anemone, Brodiaea, Calohortus, Erythronium, and Ranunculus.

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