Classification of Horticultural Crop Based on Life Span of Plants
Ex. Phlox, Mary gold.
Ex. Onion, Cabbage
Ex. Roses, Tuberoses, Chrysanthemum.
From the name it is clear that the plants live for one season or less. Annual plant is one which completed its life cycle from germination to seed formation within one season and then dies usually as a result of complete exhaustion of its food reserve in the process of reproduction. Mostly they complete their life history in 3 to 6 months. They comprise of several of most beautiful and easily grown plants, widely varying in from habit of growth and colour. Annuals are very effective, grown neither in pots or in ground. Particular annuals thrive best in particular period of the year. The annuals are conveniently grouped according to season as follows.
1. Rainy Season Annuals:
They can stand more in rain than others and therefore grown to flower during rainy season. The time of sowing then would be from April to May in most places e.g. Mary gold, Aster, Salvia, Zinnia etc.
2. Winter or Cold Season Annuals:
The thrive and bloom best during winter. These are sown in September, October e.g. phlox, Antirrithium.
3. Hot weather or Summer season Annuals:
They are sown in January – February and blooming period is April, May e.g. Sunflower, Gailardia, and Zinnia.
These plants usually requires two years or at least two growing seasons with more or less of a dormaint season or lasting season between two completed life cycle. Seed sown in spring or summer, and vegetative growth is completed in first year and in the following spring, flowering and fruiting takes place. Generally the period of growth is 6 to 9 months e.g. Gladioli, Dahlia. No hard and fast line can be drawn between annuals and biennials crops like turnip, carrot, cabbage and onion are classified as biennials.
Any plant that lives more than two years is a perennial e.g. Mango, Citrus. These crops are classified in to two groups.
Herbaceous perennials are those with more or less soft succulent stems. In Temperate climates the tips die off after seasons growth but root remains alive and produce new stem and tops on favorable conditions. In other words their tips are annual while ground parts are perennials lie many years and are classified as: a) Trees b) Shrubs c) Vines according to their habit of growth.
Trees are upright in habit and stems take the form of central axis e.g. Mango, Sapota, guava, Mandarins etc.
Shrubs have no main trunk but a number of erect or semi erect stems are seen but do not forms the main frame work e.g. Hibiscus, Rose, and Lantana Acalyphya etc.
Both woody and herbaceous have stems which are flexible and not in position to keep their branches and leaves erect. They either spread on the ground or require some support whether alive or man made e.g. cucurbit vines, Grape vines, Passion fruit etc.