Certain flowers are more pleasing to the eye than some others. That is why they need special care
DAHLIA is a large brightly coloured garden flower, often shaped like a ball. It is generally considered an erect perennial flower with opposite leaves, but those sown in pots and trays are annuals. Dahlia belongs to the family compasiteae (asteracceae). There are about 12 wild species, all natives of Mexico and south-west United States. It is said that dahlia originated in central America and was subsequently cultivated in other parts of the world. Extreme liking for it resulted in extensive hybridization and selection. Different varieties of dahlia range considerably in height. Taller varieties generally require staking, whereas the dwarf ones, 1-5ft tall, may grow on their own without staking. The genus dahlia has grown very rich and thousands of varieties have been produced in due course. The name of Dr Andrew Dahlia from Sweden can never be forgotten because of his valuable contribution to the production of a number of varieties of the flower. It is because of this fact that genus dahlia was named after him.
Dahlias are considered extremely beautiful flowers. They enjoy an elevated status throughout the world, because their flower-heads possess a diversity of petal forms and a wide range of colours, from white to rich yellow and pink to red and purple. The colour of their petals is either uniform or double in colour, giving them a novel look. With respect to size, the flowers are classified as miniature (under four inches); small (four-seven inches); medium (seven-nine inches); large (nine-10 inches) and giant (over 10 inches).
CULTIVATION: Based on local weather conditions, dahlia can be propagated from seeds, tubers and cuttings. In case of shoot cuttings, tubers are sown comparatively earlier and two-three inches cuttings of tender shoots are obtained. These are initially planted in small pots and transferred to plots after about 25-30 days. For a healthy growth of the plants and proper size of the flowers, heavy fertilization is very important. Some of the initial ingredients for successful cultivation are briefly mentioned below:
PLANTING SITE: Dahlias require sunny locations. For their cultivation, a sheltered site which is not overshadowed by plants is generally recommended — and windy places should be avoided. In their initial stages, dahlias require proper care, but once they get established hardly much care is needed. The beds are dug about 2.5 feet deep. They are mixed with a mixture of soil, well rotted cow-dung in sufficient quantity and decayed leaf manure, bone meal, wood ashes and river sand. Watering is necessary once or twice a week so that the soil may settle down properly before the planting time. A top-dressing with blood meal, fish and bone meal at 4 oz/sq.yd is preferable immediately after planting.
METHOD OF PLANTING:
(1) Pot plants: They are produced by seeds sown generally from September to October. Dahlias should be planted at a suitable distances. Pot-plants, while still in their pots, have to be watered one-two hours prior to their planting in the soil. Plants four-five feet in height are planted about three feet apart. Proper care has to be taken while shifting the plants to the soil so that the roots may remain intact. The plants are watered thoroughly after transplantation.
(2) Dormant tubers: They are planted directly in the prepared beds. A planting hole about nine inches across and 1.5ft deep is dug and the tuber is placed in it and covered by compost already prepared. The position of tuber is marked by fixing labelled supported canes of appropriate size. The tuber generally takes five-six weeks to develop a shoot above the ground.
(3) Root and shoot cuttings: Root cuttings are planted carefully so that roots may not get disturbed. The plants are watered moderately as the growth develops. They are mulched with well-rooted manure when they are about 12-15inches tall, so that the soil may remain moist. To avoid rot, the mulch has to be kept away form the steam base.
For shoot cuttings, the tubers are sown rather early and the cuttings of appropriate size already mentioned earlier are produced from the growing shoots. They are planted in pots and transplanted after a period of 20-30 days.
WATERING AND DRAINAGE: Due to vigorous growth, dahlias require plenty of water at almost all the stages of its growth. However, proper drainage is necessary and the water should not be allowed to accumulate. Watering on alternate days is generally recommended. It depends on prevailing weather conditions.
FEEDING THE PLANTS: Feeding with potassium fertilizes at the time of budding is important, as it produces good flower colour and strengthens the stems. For general purpose, cow-dung manure in combination with decayed leaf manure is used.
WEED CONTROL: Proper mulching around the stem base discourages the weeds from growing. However, removing them through hoeing every two-three weeks would keep the plants free from weeds. In case hoeing is not done, the weeds would use a considerable amount of fertilizer meant for dahlia plants, and thus, make them look frail.
PINCHING AND DISBUDDING: When the plants are gown sufficiently tall (depending on their variety), further growth may be stopped by removing the growing points to encourage side-shoots. At this stage, additional stakes are fixed if needed so that the plants remain in their position. The smaller the number of shoots, the bigger would be the flowers. For giant or large blooms, the plant is restricted to only four-five shoots, but for medium and small blooms seven-10 shoots.
While disbudding, it is important to maintain the symmetry of the plants so that they may look balanced.
TUBER STORING: In autumn, when the plants get dry, the stems are trimmed to about six inches. The tubers are lifted along with stumps and cleaned from the soil. The roots are trimmed and the tubers are treated with any suitable fungicide. Finally, they are stored in a clean, dry and cool place to be used in the next season.
PESTS AND DISEASES: Dahlias are generally affected by aphids, thrips, red-spider-mites and earwigs. They are equally susceptible to meanly bugs and scale-insects in hot and humid climates. These are all common insects and can be easily controlled through regular sprays with any suitable insecticide. In case slugs are observed, any slug bait available in the local market may be applied at the earliest. In case of viral infection, the plant is uprooted and burnt at the first sight as there are no curative measures available.
Certain flowers are more pleasing to the eye than some others. That is why they need special care 
