Gardeners often refer to any underground root used by plants to store food and energy for next season's blooms as bulbs. True bulbs are layered and contain the components of a new plant inside the bulb much like a seed. Other enlarged roots like corms, rhizomes or tubers serve the same purpose, although their structure is a bit different. Each makes and stores food from sunlight and requires the same basic care after blooming.
Remove faded blooms, but do not cut back foliage. Blooming depletes bulbs of their energy and it must be replenished in order to produce next year's flowers. Plants gather energy from the sun through the leaves and convert it to usable energy in the form of carbohydrates, sugars and proteins. Energy that is not needed to sustain the foliage is stored in the bulb for next year's flowers. Cutting back the foliage too early prevents the plant from storing the needed food for healthy growth the following year.
Apply all-purpose fertilizer to the area around the bulbs when blooming has ceased. This provides the nutrients needed for foliage to flourish and store food in the bulb. Keep the area weed free and treat any insect infestations immediately to prevent damage to foliage. Healthy foliage means the plant can use its energy to make food for next year's plants.
Water when the soil dries and keep soil moist. Stop watering when leaves yellow and die back. Foliage can be cut at this time, as it is no longer needed to produce food. Some plants continue to grow and produce lush foliage until fall, while others die back in mid summer.
Dig and store tender bulbs in the fall as soon as the foliage has dried. Use a garden fork or spade to dig under the bulbs and lift them free of the soil. Allow to dry in a shaded area for 2 to 3 days. Place 2 to 3 inches of peat moss in a cardboard box and layer bulbs in the peat moss. Cover with 2 inches of peat moss and repeat. Do not add more than three layers of bulbs. Moisten lightly and store in a cool area--between 40 and 55 degrees F--until spring.
Hardy bulbs remain in the soil over winter and produce new blooms in early spring. Divide hardy bulbs by lifting and separating the bulbs in late summer. Replant in a location with similar growing conditions. Water thoroughly and keep the soil moist until the ground freezes in the fall. A layer of straw mulch prevents heaving during winter freezes and thaws and protects bulbs from winter damage.