60-second guide: plant types
By Julie Hollobone
The least you need to know about garden plants at a glance
Annuals Annuals grow, produce seed and die all in one growing season, which lasts up to a year. Many, such as sweet peas, nasturtiums, love-in-a-mist and Alyssum, offer quick, reliable colour.
Half-hardy annuals Hardy annuals tolerate our winter temperatures, either as seeds in the soil or as small seedling plants. Many cast their own seeds, which germinate at soil temperatures of about 10ºC (50ºF) for more flowers next year. You can sow the seed into compost in late summer or early autumn for early-flowering plants next year.
Half-hardy annuals, such as cosmos and French marigolds, cannot normally survive our winter temperatures and need a soil temperature of about 18-20ºC (64-68ºF) for seed to germinate. You can sow the seeds indoors, or in a heated greenhouse, sometimes as early as February, for flowering plants in June.
Biennials Biennials grow from seed into a small plant in the first growing season, survive the winter and flower the following year, then produce seed and die. Typical plants include native foxgloves (Digitalis purpurea) and honesty (Lunaria annua). If you want flowers from them every year, sow the seeds for at least two years running and then allow them to self-seed for following years.
Bulbs and bulbous types True bulbs such as Allium and Narcissus comprise layers of compact scale leaves that store food and surround a flowering shoot. Once dormant, you can store and use bulbs the following season.
Corms, such as crocus and Crocosmia, are compact stems of stored food from which leaves emerge. As top growth develops, the original corm shrivels and a new corm forms above the old. To keep the new corm from rising above the soil, contractile roots pull the new corm downwards.
Tubers are either swollen stems or roots that act as a food store and grow in size each year.
Climbers Climbers attach themselves to walls, trees, fences etc by means of tendrils with suckers, or aerial roots, and grow towards the light. Some are annuals, others tender perennials and many are woody-stemmed perennials.
Perennials Perennials live for more than two years and usually for much longer. All trees and shrubs are perennials, as are many climbers, flowering border plants and bulbs. Herbaceous perennials grow leafy shoots from the soil in spring, flower and then produce seed. In winter, the roots remain dormant and then put up new shoots the following spring.
Shrubs are woody perennials that are generally multi-stemmed, or branch from a single stem at a low level. They tend to be smaller than trees.
Tender perennials generally can't endure cold winters if left outside, but will grow for years protected in a greenhouse or on a bright windowsill. Pelargoniums, fuchsias, petunias busy Lizzies, bananas and palms are examples.
Woody perennials produce woody stems as they grow larger to support the ever-increasing weight of branches and foliage. They may keep their leaves in winter, or lose them in autumn.
Trees are woody perennials that tend to grow on a single stem and may begin to branch at least 1m (3ft) above the ground.
How hardy? Fully hardy plants will survive temperatures of below –5ºC (23ºF) for several days at a time.
Frost-hardy plants can only tolerate temperatures down to –5ºC (23ºF), while half-hardy or tender plants cannot usually endure temperatures lower than 0-5ºC (32-41ºF) for any length of time.
Feature adapted by Sarah Brocklehurst.
For further gardening advice, hints and tips, go to www.gardensmonthly.co.uk