Tuberose is a member of the Amaryllidaceae family. Its English name is tuberose and its scientific name Polianthes tuberosa. The flower is native to Mexico. In a vase it stays fresh for 7-10 days and fills the room with fragrance every night. Because demand for it keeps growing in Bangladesh, it is now cultivated commercially on a considerable scale.

Tuberose is very popular as a fragrant flower. Its Bengali name, rajanigandha, comes from the fact that it opens in the evening and spreads its scent at night. In terms of demand and commercial value it has no equal. As a cut flower for vases it is unique. It is also used to make garlands, bouquets, hair braids and crowns, and perfumes are made from its extract.

Based on flower size and petals, three classes of tuberose are found:

• Single: the petals are in a single row. The flowers are pure white and very fragrant.
• Semi-double: the petals are arranged in two or three rows.
• Double: there are more than three rows of petals. The edges of the petals have a light red tinge and the flowers are less fragrant.

Single and double tuberose are found in Bangladesh, but no variety has yet been developed.

Tuberose propagates by both seed and bulbs, but in Bangladesh it is usually grown from bulbs. The onion-like bulb found at the base of each plant is called the bulb. Old plants carry many bulbs in a clump at the base, with the central one the largest. Medium to large bulbs are usually used for propagation. Large bulbs produce healthy plants that flower early, while small bulbs produce weak plants that flower late. Plants grown from bulbs keep all the traits of the mother plant and flower in a short time. In winter the bulbs usually lie dormant under the soil, and at the end of winter they become ready for planting.

Tuberose likes warm, humid weather, so in Bangladesh it is grown in summer. Successful cultivation needs an average temperature of 20-30 degrees Celsius and humid weather. Well-drained loam rich in organic matter is best.

The land should be ploughed 4-5 times and prepared well. At the final ploughing, depending on fertility, 5-10 tonnes of cow dung, 250 kg of phosphate and 200 kg of MP fertiliser per hectare should be mixed well into the soil. Three weeks after planting the bulbs, when the new plants start to grow, half of 300 kg of urea per hectare should be applied as the first top dressing, and the other half when the flower spikes emerge. For good-quality flowers, 12 kg of boric acid and 8 kg of zinc sulphate per hectare can be applied.

Source: Staff Correspondent. First published in Bengali on The Agro News.