Resource Book on Horticulture Nursery Management

transplanting in the field. When they are seeded it requires thinning. Hardy annuals can
survive low temperatures and some light frost, while tender annuals cannot tolerate low
temperatures during cold and should be planted only after there is no more danger of
frost. Half-hardy annuals can tolerate some cold temperatures, but are usually killed by
frost. Annuals make excellent space fillers for the perennial garden.
Biennials
The plants which complete their life cycle in two years are called as biennials. They
complete their vegetative growth during first year and flowering or regenerative phase
during second year. Although are not quite as permanent as perennials, many biennials
re-seed themselves, becoming comparable in performance to perennials. Biennial seeds
that are planted one year will not flower until the following year. Foxglove, Hollyhock
and Iceland poppy are biennials.
Perennials
These are the most versatile plants. These are the plants which have life for more
than two years. Generally they have life of three to four years few of them may extend
their life for four to five years. Most of them have dormancy during winter and blooms
during rest of the period. They are good border plants e.g. Dahlia and Perennial phlox.
They are growing in many colors, shape, texture and scent. They are very popular as
borders, interplants with annuals and foliage plants.
Introduction of New Plants
The plants which are introduced from exotic source or other locality are called as
introduced plants. Some of the valued, novelty plants are being brought from the places
where they are available. Many flowering annuals were introduced from Europe and
America during British regime. The wild and cultivable plants of African origins were
also introduced.
Indoors
The plants can be raised in shade like, corridors, verandah, windows, balconies,
patios, conservatories, and indoors. The choice of the plant depends upon the interest and
purpose of the collection. They grow well either in shade or semi shade with filtered
light. Some of them grow well in full shade. Some indoor plants need 4 to 6 hours of
sunlight either in the morning or evening.
Bulbs
This class of plant consists of true bulbs, corms, rhizomes, tubers and tuberous roots.
� True bulbs have an internal flower bud surrounded by layers of food supply.
� Corms are stored food, which consists of roots at the base and small buds at the
top. Crocus and gladiolus are examples of corms.
� Tubers are the round food-storing part of a stem and flowers are developed within
them. Tuberous roots are the food storing part of roots. Dahlia and tuberous
begonias are produced from tuberous roots.
� Rhizomes are similar to tubers, but they are long.
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