Tuberose Cultivation: Species, Varieties, and Growing Techniques

Tuberose (Polianthes tuberosa L.), known as Rajanigandha in Hindi, is one of the most commercially important bulbous ornamental crops in India. Prized for its waxy white flowers and intense fragrance – especially strong during evening hours – tuberose finds wide use in garland-making, cut flower arrangements, essential oil extraction, and the perfume industry. Native to Mexico, the plant was introduced to India via Europe during the 16th century and has since become a major floriculture crop cultivated across states like West Bengal, Tamil Nadu, Karnataka, Maharashtra, and Andhra Pradesh.

Botanical classification and plant description 🔗

Tuberose belongs to the family Amaryllidaceae (sometimes classified under Asparagaceae). It is a half-hardy, perennial, bulbous plant. The bulbs consist of scales and leaf bases, with the stem concealed within them. The roots are mostly adventitious and shallow. Its flowers have a funnel-shaped perianth, are fragrant and waxy white, and measure roughly 25 mm in length. The leaves are narrow, strap-like, and bluish-green, growing up to 30-45 cm long from a basal rosette. Flower spikes can reach 60-100 cm in height and bear florets that open progressively from the bottom upward.

The name Polianthes comes from Greek – polus (many) and anthos (flower) – reflecting the plant’s abundant blooming habit. The species name tuberosa refers to its tuberous underground storage organ, which is the primary means of propagation.

Types and important varieties of tuberose 🔗

Tuberose varieties are broadly grouped into four types based on flower structure:

Single-flowered types 🔗

Single types have one whorl of corolla segments and are highly scented, making them the preferred choice for concrete (essential oil) extraction. Their concrete content ranges from 0.08 to 0.11 per cent. They are also widely used as loose flowers for garlands and floral ornaments. Key single varieties include Calcutta Single, Mexican Single, Hyderabad Single, and Kalyani Single.

Semi-double types 🔗

Semi-double varieties bear two to three whorls of petals and are used for both concrete extraction and as cut flowers.

Double-flowered types 🔗

Double types have more than three whorls and are primarily used for cut flowers and bouquets. Important double varieties include Pearl Double, Kalyani Double, Calcutta Double, Hyderabad Double, and Suvasini.

Variegated types 🔗

Variegated varieties display white or yellow streaks on their leaves. The National Botanical Research Institute (NBRI), Lucknow developed two variegated varieties – Rajat Rekha and Swarna Rekha – through gamma irradiation. Rajat Rekha is a single-flowered type with silvery white leaf streaks, while Swarna Rekha is a double-flowered type with golden yellow marginal streaks.

Notable hybrid varieties 🔗

Several improved varieties have been released by the ICAR-Indian Institute of Horticultural Research (IIHR), Bangalore:

Shringar: Developed from a cross between Single and Double types, Shringar bears single-type flowers on sturdy spikes with slightly pinkish buds. It is resistant to root-knot nematode (Meloidogyne incognita) and yields about 40% more loose flowers than Calcutta or Mexican Single.

Prajwal: This hybrid from the cross Shringar × Mexican Single produces single-type flowers on tall, stiff spikes. It yields about 20% more loose flowers than Shringar and is recommended for both loose and cut flower purposes.

Suvasini: A multi-whorled variety from the cross Single × Double, Suvasini produces pure white, bold flowers on long spikes suited for cut flower use. It records about 25% higher yield than the standard Double variety.

Vaibhav: Developed by IIHR, Vaibhav is a semi-double hybrid that yields 50% more spikes than Suvasini , making it a strong choice for commercial cut flower production.

Climate and soil requirements 🔗

Commercial tuberose cultivation in India is concentrated in warm, humid areas where the average temperature ranges from 16°C to 30°C. The crop can also be grown in hilly regions up to 1,200-1,500 metres elevation. Temperatures exceeding 40°C reduce spike length and flower quality, while frost can damage both plants and flowers.

Tuberose requires full sunlight – at least 6-8 hours of direct sun daily. Growing the crop in shady or semi-shady locations drastically reduces flower yield. Extended day length (around 16 hours) promotes vegetative growth, early spike emergence, and longer flower spikes.

In terms of soil, tuberose grows in a wide range of soil types, from light sandy to clay soils, but fertile loamy or sandy loam soils with a pH of 6.5-7.5, good aeration, and drainage are ideal. The crop is highly sensitive to waterlogging, which can cause bulb rot even after brief exposure.

Propagation methods 🔗

Tuberose is predominantly propagated vegetatively through bulbs, since most varieties rarely produce viable seeds under normal growing conditions.

Bulb selection and treatment 🔗

Bulbs with a diameter of 1.5-2.5 cm are suitable for planting. Approximately 1.25-1.5 lakh bulbs (800-900 kg) are needed per hectare. Selected bulbs should be firm, healthy, and free from rot or pest damage.

Before planting, bulbs must be cleaned and treated with Bavistin (0.2%) for 30 minutes. Dipping in a 4% thiourea solution helps break dormancy. Pre-plant storage of bulbs at 10°C for 30 days has been shown to improve plant growth and flower yield.

Seed propagation 🔗

Seed propagation is possible only in single-type tuberose. Seeds germinate in 10-15 days at an optimum temperature of 26°C. However, this method is mainly used for breeding new lines rather than for commercial planting.

Micropropagation 🔗

For obtaining disease-free planting material at scale, clonal micropropagation through tissue culture using radial bulb segments is employed , though this requires well-equipped laboratory facilities.

Field preparation and planting 🔗

The field should be ploughed deep (about 45 cm) two to three times to achieve a fine tilth. Well-rotted farmyard manure at 50 tonnes per hectare should be incorporated into the soil. After preparation, the land is left for about 15 days to allow weed seeds and soil pests to be destroyed by sun exposure.

Bulbs are planted at a spacing of 30 × 20 cm or 20 × 20 cm, at a depth of 4-6 cm. About 40,000-50,000 bulbs are required per acre. The ideal planting season is March-April in plains and April-May in hilly areas.

Nutrient management 🔗

Proper fertilization is critical for good spike production and flower quality. A basal dose of FYM at 10 kg per sq m, along with single super phosphate and muriate of potash at 80 g per sq m each, should be applied 10-15 days before planting.

Nitrogen at 15 g per sq m is applied in three split doses: the first at planting, the second at 60 days after planting, and the third at the onset of flowering. Integrated nutrient management – combining chemical fertilizers with organic manures and biofertilizers – has shown improved flower quality and sustained soil health.

Irrigation and weed management 🔗

Irrigation management requires careful timing. It is essential to irrigate before planting to provide adequate moisture for sprouting, but further irrigation should be withheld until the bulbs have sprouted. During summer, water at weekly intervals or sooner if the soil dries out; in winter, irrigate every 10 days. Avoid waterlogging at all costs.

Manual weeding is effective and should be done at monthly intervals. For chemical weed control, Atrazine at 1.0-1.5 kg per hectare in 1,000 litres of water can be sprayed immediately after planting. No hoeing or weeding should be done until sprouting has occurred.

Pest and disease management 🔗

Major insect pests 🔗

The key insect pests of tuberose are thrips, aphids, and weevils. Thrips and aphids can be controlled by spraying Rogor or Metasystox at 1.75-2.0 ml per litre. Bud borer (Helicoverpa armigera) is another serious pest that damages developing flower buds.

Nematodes are particularly devastating. Root-knot nematodes (Meloidogyne incognita and M. javanica) and reniform nematodes have been reported to cause extensive yield losses. Application of carbofuran at 2-5 kg per hectare or neem at 1 tonne per hectare helps control nematode infestation.

Key diseases 🔗

Stem rot caused by Sclerotium rolfsii can be managed by soil application of Zineb at 30 kg per hectare and by reducing soil moisture or widening plant spacing.

Flower bud rot caused by Erwinia sp. results in dry rotting of buds. Diseased plants should be uprooted and destroyed, and Streptomycin (0.01%) spray can control the spread.

Leaf blight (Botrytis elliptica) and Alternaria leaf spot (Alternaria polyanth) are fungal diseases controlled by spraying appropriate fungicides like Mancozeb (0.2%) at regular intervals.

Harvesting techniques 🔗

Tuberose begins flowering 80-100 days after planting, with peak flowering from July onwards. The timing and method of harvest depend on the intended market use.

For cut flower spikes, spikes are harvested at the bud-burst stage – when 1-2 pairs of flowers have opened – preferably in the early morning or late evening. A sharp knife or secateurs should be used for a clean cut, leaving about 4-6 cm of basal scape to protect the developing bulb.

For loose flowers, individual florets are plucked by hand early in the morning when they are fully open.

Post-harvest handling of flowers 🔗

Immediately after harvest, the lower end of cut spikes should be immersed in water to extend their longevity. The typical post-harvest life of tuberose flowers is limited by the failure of developing buds to open after harvest. Proper pre-treatments can significantly extend vase life.

Pulsing spikes for 24 hours at room temperature in a preservative solution with 20% sucrose greatly improves bud opening and vase life, even after cold storage. A sugar-containing vase preservative at 1.5% concentration, combined with sucrose pre-treatment, has been found effective for improving display life.

For packing and transport, long spikes are sold in bundles of 100, wrapped in soft tissue paper or polythene, and packed in rectangular bamboo baskets or cardboard boxes. Loose flowers are packed in bamboo baskets holding 10-15 kg and covered with muslin cloth.

Bulb lifting, curing, and storage 🔗

Bulbs reach maturity once flowering ceases and leaves turn yellow and dry – typically during February-March in North India. At this point, irrigation is stopped and the soil is allowed to dry. Leaves are cut at ground level and bulbs are dug out.

After lifting, bulbs are cleaned, offsets separated for use as seed stock, and graded by size – mature bulbs (diameter greater than 1.5 cm) and immature bulbs (less than 1.5 cm). Cleaned bulbs are placed on shelves to cure. Artificial heat of 27-35°C can hasten curing.

Bulbs should be turned every few days to prevent fungal attack. Treating with 0.2% Bavistin or Mancozeb powder before storage further protects against rot. An ambient temperature of at least 18°C for four to six weeks stimulates good-quality bulb development for the next season.

Ratooning in tuberose 🔗

Ratooning allows growers to get an additional crop cycle without replanting. When temperatures rise again after winter dormancy, the crop regains growth from previously planted bulbs. The ratoon crop produces more spikes but with fewer florets, shorter spike length, and lower flower weight. Therefore, ratoon crops are best used for loose flower production or oil extraction rather than cut flower purposes.

For ratooning, yellowing plants should be twisted from ground level to hasten bulb maturation. Fertilizer should be applied in two equal split doses – in January-February and again in April.

Essential oil extraction 🔗

Tuberose concrete is a high-value product in the global perfume industry. Flower oil is extracted through enfleurage or solvent extraction with petroleum ether. Freshly picked, unopened flowers are used for enfleurage – about 150 kg of flowers yield 1 kg of absolute. Solvent extraction yields 0.08-0.14% concrete, and one hectare can produce up to 12 kg of concrete over a three-year period.

Yield potential 🔗

One hectare of tuberose can produce 4-5 lakh spikes per year from single-type varieties, along with about 10.5 tonnes of loose flowers per hectare. Additionally, about 20 tonnes of bulbs per hectare can be harvested after 2-3 years. Yield varies with variety, spacing, and local climate conditions.

What do you think? With India being a leading tuberose producer, which variety do you think has the best commercial potential for your region – a highly fragrant single type like Prajwal for the perfume market, or a high-yielding double type like Vaibhav for the cut flower trade? How might integrated approaches to nutrient and pest management improve sustainability in tuberose cultivation?

References

1. https://www.iihr.res.in/varieties-crop-name/tuberose
2. https://www.indianjournals.com/article/chr-7-1-002
3. http://eagri.org/eagri50/HORT281/lec41.html