AN INTRODUCTION TO BULBS

The term ‘bulb’ refers to a plant’s underground vertical shoot which usually has thickened leaf bases (i.e. modified leaves) that serve as food storage centers. The food stored in the bulb is used to nurture the plant in its time of dormancy. This allows the plant to survive adverse conditions with a self sufficient food supply for quite some time. In some cases, the thickened leaf bases may overlap and surround the center of the shoot (for example, in lilies) or surround the bulb’s inner parts (onions for example).

A BULB’S LIFE

Bulbs are usually perennial i.e. living at least two years without perishing. After their period of growth and flowering, bulbous plants go into dormancy. Spring bulbs cease growing in late spring or in early summer and start re-growing in autumn.

TYPES OF BULBS

General plant bulbs can be divided into five main types on the basis of their storage structure. These are: true bulbs, corms, tubers, tuberous roots, and rhizomes.

TRUE BULBS

True bulbs are characterized by the presence of five main parts: the basal plate (bottom of bulb that lets out the root), fleshy scales (storage tissues), tunic (skin-like protective cover over the fleshy scales), the shoot (growing flower and leaf buds), and lateral buds. True bulbs are subdivided into two types. One of these is the tunicate bulb with a papery covering (called tunic) which serves to protect the scales from drying and from injury. Daffodils, tulips, and hyacinths are all examples of true bulbs. Imbricate bulbs lack the tunic and hence need to be kept moist all the time, before planting, in order to prevent them from drying out. Lilies are the prime example of imbricate bulbs.

CORMS

A corm is a plant bulb formed by the swollen base of stem that acts as the storage tissue. Unlike true bulbs, corms do not show storage rings when cut in half. Gladiolus, crocus, and autumn crocus are well known examples of plants with corm type bulbs.

TUBERS

Unlike both a true bulb and a corm, a tuber lacks a basal plant from where roots develop and it also lacks a tunic. The potato is the most famous of all the tuberous plants. Other plants with tuber type bulbs include caladiums, oxalis and anemones.

TUBEROUS ROOTS

In tuberous roots, the nutrients are actually stored in roots rather than in the enlarged underground stem. Dahlia and begonia are examples of plants with tuberous roots.

RHIZOMES

The distinguishing feature of rhizomes is that they grow horizontally underground. They can become quite invasive in, for example, plants like lily of the valley.

FLESHY ROOTS

Some plants have fleshy roots that resemble bulbs but are not bulbs as such. These roots store the nutrients. Daylilies and peonies are examples of such plants.

PLANTING BULBS FOR A FLOWER BULB HOME GARDEN

Flower bulbs offer rich source of choices to adorn your yard with a variety of colors. Much needs to done but, if you are a true flower bulb lover, you will think it is certainly worth it. The following is a stepwise guide to growing your flower bulb home garden.

PREPARE THE SOIL

The primary requirement for growing your flower bulbs is preparing the right kind of soil. Soil should allow good soil drainage. Adding compost, or some other type of organic content in the top 300mm to 455mm (12 to 18 inches) of soil makes the right kind of soil for planting bulbs.

USING FERTILIZERS

Phosphorous is an important element for the development of roots. For better results, phosphorus should be mixed in below the bulbs. You can use blood & bone or use composted cow manure in the lower part of the soil while preparing the planting bed. Additional fertilizers are needed if you want to maintain the plant bulbs for more than one year in the beds. Remember not to fertilize spring flowering bulbs once they start flowering. It can cause the bulbs to rot and shorten the life of the flowers. For summer and fall flower bulbs, fertilizer should be added monthly. It is worth remembering that bulbs flourish best in soil with a pH range of 6 to 7. A soil test is, therefore, a good idea. If the soil is acidic you can add gypsum & composted horse manure to balance it.

LOCATION AND DEPTH OF PLANTING BULBS

Where to plant the bulbs depends mainly on the light requirements of the individual species of plant. For example, spring bulbs can grow successfully under shade (trees or shrubs) while summer flowering bulbs need full or partial exposure to the sun. Spring bulbs planted on southern slopes and hillsides bloom earlier.

As for the depth of planting spring bulbs, measure how tall the bulb is and multiply this measure by 2 or 3. Plant the bulb this deep in the soil. Larger bulbs (tulips and daffodils etc.) should be planted some 200mm (8 inches) deep while smaller ones are best planted 75mm to 100mm (3 to 4 inches) deep. Summer bulbs need different depths so get the information from the person selling you these bulbs.

WATERING THE BULBS

After planting the bulbs, water them. This settles the plant in the soil and provides moisture to the bulb so it can start the process of root formation. It is important for the planted autumn bulbs to develop roots before winter. For summer and spring bulbs, watering should start with the appearance of the first buds on the plant, provided that the soil is dry. In all cases, avoid over watering bulbs since it can cause rot.

DIGGING AND STORING BULBS

During summer, spring bulbs remain dormant. If you need to dig up the bulbs this is the right time. Store them in a place with good ventilation and plant again in Autumn. With summer bulbs you need to wait until the leaves of the plant turn yellow before digging them up. Keep humidity to a minimum in your storage place.