After reading this article you will learn about the planting of bulbous plants.
In nature, there are certain plants which have modified underground stems in which food material is stored to overcome the unfavourable season.
Botanically, plants propagating themselves through modified underground stems are grouped into four group’s viz.:
(i) Tubers-Dahlia,
(ii) Corms-gladiolus, Freesia,
(iii) Bulbs-Amaryllis, Tuberose, Zephyranthes, Crinum and
(iv) Rhizome-Canna and Iris.
But horticulturally, plants of all these four groups are called as bulbous plants. These plants are prized for their magnificent flowers and for being grown for mass effect (e.g. Dahlia, Canna, Zephyranthes), cut flowers (e.g., Gladiolus, Tuberose, Amaryllis), pot plants (e.g., Amaryllis, Dahlia), for extracting essential oils (e.g., Tuberose). They are suitable for various situations and are fitted in landscape plants.
These bulbous plants are divided into two categories i.e., hardy and tender bulbs. The hardy types can be left in the ground and are separated after 2-3 years for their multiplication (e.g. Amaryllis, tuberose, canna, zephyranthes, crinum etc.).
On the contrary, the tender types cannot be left in the ground after flowering and are to be lifted from the ground on maturity. After their treatment against diseases, these are to be stored in cold storage or cool places during off season for next year planting e.g., Gladiolus, narcissus, Daffodils, Freesia, Dahlia, etc.
Climate:
In general, cool weather, high atmospheric humidity and moist soil conditions are congenial for the manufacturing of food, better production of high quality flowers and bulbs. According to climatic requirement of these bulbs, they are grouped into two categories i.e., Warm climate—Canna, Dahlia, Tuberose, crinum, Zephyranthes, etc., and cool climate—Gladiolus, Narcissus, Daffodils, Freesia, etc. Modified environmental conditions are to be provided during winter and summer seasons for the production of high quality blooms.
Soil:
Soil should be sandy loam or loamy sand in texture for better production of bulbs. It should be moderately fertile with good water holding capacity, and with pH ranging between 7.0-8.0. For pot culture the ideal pot mixture should contain 2 parts sand: 2 parts leaf mould: 2 parts well rotten farmyard manure: 1 part soil and ½ part charcoal.
Propagation:
The following are the common methods employed for propagation of bulbous plants:
(i) Off-sets, cormlets or bulblets:
Mother bulbs produce many bulblets, which are separated and planted for raising new crop. The intensity of bulblet production is a varietal character. Some varieties are very prolific bulblet producer whereas some produce sparse bulblets. It takes about 1-2 years for growing a bulblet into a full bulb.
(ii) Division:
It is followed in tubers, rhizomes and corms which are divided carefully (in such a way that each piece contains at least one vegetative bud) and planted in the soil.
(iii) Terminal cuttings:
These cuttings are mostly employed to propagate Dahlia and Rex Begonia.
(iv) Seed:
This method is employed by the breeders to create new varieties, e.g. Gladiolus, Dahlia, Freesia, Amaryllis, Lilies, etc.
Manuring:
Well rotten farmyard manure @ 5 kg/sq. m should be incorporated at the time of soil preparation. The application of 20 g each of P2O5 and K2O/sq. m has also been found beneficial at the time of planting bulbs. Nitrogen @ 40 g/sq. m into two-three splits should be applied.
Planting of Bulbs:
The planting time for different bulbs is different. In North India plains the planting of Gladiolus, Narcissus, Daffodils, Iris, Dahlia, etc. can be done from mid of September to mid of November. If planting is done in succession the time of flower production, will also be longer. Amaryllis is separated in November and is planted. Tuberose and Zephyranthes are separated and planted in February-March. Canna is planted in July with the onset of rains.
The depth of planting of bulbs also differs according to the type of bulb. Generally, bulbs are planted at 7-10 cm depth except few lilies which are planted at 25-30 cm depth. By planting the bulbs at different depths, the flowering period can be extended. The distance between rows and plants are varied according to the purpose of growing. Generally distance of about 30 × 20 cm is maintained.
Intercultural Operations:
Weeding and hoeing:
Weeds should not be allowed to grow and should be removed as soon as they appear otherwise they compete for nutrients and water with the main crop. Hoeing helps in aeration of soil and better development of bulbs. In early stages of growth frequent weeding and hoeing are required.
Irrigation:
Liberal application of water at all stages of development is highly beneficial. Generally 7-10 days interval is appropriate in winter whereas in summer it should be about 5-7 days.
Staking:
Bulbous plants like Gladiolus, Dahlia, Lilies, etc. produce flowers on long stem and thus need support. Otherwise spikes may bend down and break with strong winds. Bamboo stakes can be provided.
Harvesting of flowers:
The stage of harvesting of flowers depends upon the distance of travel. It varies with the kind of flower. For local market, gladiolus and tuberose should be cut when lower 2-3 florets have opened. Whereas for distant market, flowers are cut when basal florets show colour. Narcissus and Daffodil are cut at goose neck stage. Before harvesting the flowers, plants should be irrigated.
Lifting of bulbs and their storage:
Tender bulbs like Gladiolus, Dahlia, Narcissus, Daffodils, etc. are to be dug from the soil 10-12 weeks after flowering has been finished. Before lifting the bulbs, water is withheld. After digging, bulbs are dried in shade for few days. Then these are treated with 0.2% Bavistin solution for 30 minutes and thereafter stored. Hardy bulbs are separated after 2-3 years and are again planted in the planting season.