A-Z of Annual and Biennials
Annuals and biennials flower just once, yet their ability to grow quickly from seed and their magnificent array of bright colours have earned them an affectionate place in every gardener’s heart. Many of our most popular annuals (including petunias, begonias, marigolds and asters) come from the tropics. These annuals are half-hardy in Britain and cannot be moved outdoors until all danger of frost has passed. Sterile compost and heat are a must if seeds are to germinate or the seedlings to make steady growth. The extra attention is repaid, however, by long-lasting shows ofin the most brilliant colours.
Hardy annuals, such as pot marigolds, Californian poppies and sweet peas, are much less trouble, sprouting readily from seed. They ask little more than decent, a sunny or lightly shaded position, weed-free surroundings and sufficient water.
Whether hardy or half-hardy, annuals are the faithful standbys of many gardeners, filling gaps in, providing cut flowers for the house and dying away without fuss at the end of the season.
Biennials, too, flower only once, but in their first year of growth, tucked away in a spare piece of land, they develop only roots and leaves, deferring the flowers until the second year. Like annuals, biennials are an essential element of the– wallflowers, forget-me-nots and polyanthus primroses in spring, and in summer such all-time favourites as Canterbury bells, hollyhocks and foxgloves.
Easy to grow from seed, annuals in all colours and sizes offer a chance to try new partnerships every year.
There are so many annuals with so many different habits and such a range of size that their uses are limited only by the imagination. Choose from the true annuals -there is everything from the 2.4m (8ft) tall sunflower to the sweet alyssum, at only 7.5cm (3in) – the sturdy biennials and the tender perennials treated as annuals.
Popular annuals, such as marigolds, lobelias and ageratums are widely used in summer bedding schemes, or containers and window-boxes. They can be bought in trays or strips but seed is much cheaper than plants and the sweeping range available encourages experimentation.
There are dozens of annuals suitable for the less formal mixed border. Sow them in gaps between perennials or in the spaces left by spring bulbs. Treat them as temporary features, useful until their partners have reached maturity, or resow them yearly to become part of the overall scheme.
Hardy favourites – corncockle, cornflower, corn marigold and field poppy – once common growing wild in cornfields, are worth sowing together for their nostalgic associations and their simple, en-during charm.
Annual climbers, such as sweet peas, morning glory, and nasturtiums (Trapaeolum peregrinum) provide quick and cheap decoration for fences and walls.
For tropical foliage colour effects, sow castor-oil plant (Ricinus), coleus, kochia and Zea mays ‘Gracillima Variegata’.