Bulbs

A true bulb is a complete or nearly complete miniature of a plant encased in fleshy leaves called scales that contain reserves of food. Generally, however, a flower bulb is considered to be any plant that has an underground food storage capacity. Bulbs fall into two main categories: spring-flowering, which are planted in the fall, and summer-flowering, which are planted in the spring. A better grouping might divide bulbs into hardy and tender varieties. As a rule, spring-flowering bulbs are considered hardy. They are usually planted in the fall before the first frost and can survive the winter months. They provide early color before most perennials and annuals. Summer-flowering bulbs, on the other hand, are tender and cannot survive harsh winters. They should be planted in the spring after the last frost.

Bulbous plants can be annuals or perennials and can be grown from true bulbs, corms, tubers and rhizomes. Corms are the base of a stem that becomes swollen and solid with nutrients; it has no fleshy scales. The tuber, which is an underground stem that stores food, differs from the true bulb or corm in that it has no covering of dry leaves and no basal plate from which the roots grow. Usually short, fat and rounded, it has a knobby surface with growth buds, or eyes, from which the shoots of the new plant emerge. Tuberous roots are the only ones from this group that are real roots. Their food supply is kept in root tissue, not in stem or leaf tissue as in other bulbs. Rhizomes, also called rootstocks, are thickened stems that grow horizontally, weaving their way along or below the surface of the soil and at intervals sending stems above the ground.

Use 1 pound of Vigoro^® Ultra All Purpose Plant Food 12-5-7 or Vigoro Bone Meal for a 5 by 10 foot area or a small handful for a cluster of bulbs. Place a 1- to 2- inch layer of organic matter over the bed. Thoroughly mix the fertilizer and organic matter with the soil. For individual planting holes, loosen the soil below the depth the bulb is to be planted. Add fertilizer and cover with a layer of soil (bulbs should not contact fertilizers directly). Set the bulb upright in the planting hole and cover with amended soil.

It is best to check correct planting depth for each bulb with a successful local grower or other good local source. As a general rule, bulbs should be planted 2 to 3 times the diameter of the bulb in depth. It is important not to plant bulbs too shallow, as this will encourage frost heaving. Normal rainfall usually provides enough moisture for bulbs. But during dry weather, water plants at weekly intervals, soaking the ground thoroughly. Be especially careful not to neglect bulbs after blooming.

Mulching: In the winter, mulch bulbs 2 to 4 inches deep with organic material such as straw, pine bark, hay or small ground leaves. A winter mulch prevents alternate freezing and thawing which damages bulbs and plant roots. Apply mulch after cold weather arrives. You may damage the bulbs if you mulch while soil temperature is still high. Remove mulch as soon as danger of severe freezing has passed in early spring. If mulch is left on the ground after new growth starts, tops of the new shoots will be pale green or colorless, and new stems and foliage may be broken.

After bulbs bloom, fertilize them lightly with Vigoro All Purpose 10-10-10 or Vigoro Bone Meal. Use no more than 1 pound for a 5 by 10 foot bed. Avoid high-nitrogen fertilizer. Be sure to keep fertilizer off the leaves and away from the roots; it will burn them. In addition to the Vigoro All Purpose 10-10-10 or Vigoro Bone Meal, you can use bone meal as an extra source of phosphorus.

Buying Bulbs

Spring bulbs usually become available toward summer's end. Summer bulbs become available in early or mid-spring. Look for plump, firm bulbs. Select on a basis of color, and size for intended purposes. For example, small bulbs are good for naturalizing and large ones to stand out as specimen plants. If bought before planting time, keep bulbs cool (60°- 65°) and dry until planting. Temperatures higher than 70° will damage the flower inside the spring-flowered bulbs. Rhizomes, tubers, and tuberous roots are more easily desiccated than bulbs and corms and should be stored in peat, perlite or vermiculite.

Establishing Bulbs

As a general rule, the colder your climate, the sooner you should plant spring-flowering bulbs. They always should be planted before the first frost.

Most bulbs need full sun. Select a planting site that will provide at least 5 to 6 hours of direct sunlight a day. Bulbs left in the ground year after year should have 8 to 10 hours of daily sunlight for good flowering.

Good drainage is the most important single factor for successful bulb growing because most bulbs will not tolerate poor drainage and rot easily in wet areas. Beds should be dug when the soil is fairly dry. Wet soil packs tightly and retards plant growth. Spade the soil 8 to 12 inches deep. While digging, remove large stones and building trash but turn under all leaves, grass, stems, roots and other objects that will decay.

When flowers fade, cut them off to prevent seed formation, which takes stored food from the bulbs. If leaving bulbs in place for bloom next year, do not cut the leaves after flowering until they start to wither. Green leaves produce food for plant growth next year. After leaves turn yellow, cut and destroy the stems and foliage of the plants. Dead foliage left on the ground may carry disease to the new growth next year. If moving bulbs from one place to another, or if a planting has become crowded and ceased blooming, move only after the foliage has faded. Bulbs dug and moved before foliage fades are useless.

Many summer-flowering bulbs should be dug and stored, as they are tender. This is done when the leaves on the plants turn yellow. Use a spading fork to lift the bulbs from the ground. Wash off any clinging soil except those that are stored in pots or with the soil around them. Spread the washed bulbs in a shaded place to dry. When dry, store them away from sunlight in a cool, dry basement, cellar, garage or shed at 60°-65°. Avoid temperatures above 70° or below 50°. Be sure that air circulates around stored bulbs. Never store them more than two or three layers deep as that generates heat and causes decay. Leave the soil on achimenes, begonia, canna, caladium, dahlia and ismene bulbs. Store these bulbs in clumps on a slightly moistened layer of peat moss or sawdust in a cool place. Rinse, clean and separate them just before planting.