Many plants can be increased in several ways; some are complicated, while others are straightforward, although the development of new plants may not be rapid. Layering, for example, is easy, but rooting takes several months. Throughout this book, where possible the easiest way to increase specific plants is explained.
Part of this practical, all-colour book encompasses an A–Z of popular garden and indoor plants and the ways in which they can be increased. It is arranged alphabetically by current botanical name, but earlier botanical names are included. There is also information about each plant’s growth habit – whether annual, biennial, herbaceous, shrub, tree or climber – to enable you to gain a greater understanding as to why a plant is increased in a particular way. The common names index will help you find the right plant quickly. With this easy-to-follow book at your elbow, it becomes possible to increase most plants growing in gardens or indoors.
About the author
David Squire has a lifetime’s experience with plants, both cultivated and native types. Throughout his gardening and journalistic careers, David has written more than 80 books on plants and gardening, including 14 books in this Specialist Guide series. He also has a wide interest in the uses of native plants, whether for eating and survival, or for their historical roles in medicine, folklore and customs.
Measurements
Both metric and imperial measurements are given in this book – for example, 1.8 m (6 ft).
SEASONS
Throughout this book, advice is given about the times of the year to raise new plants. Because of global and even regional variations in climate and temperature, the four main seasons have been used, with each subdivided into ‘early’, ‘mid-’ and ‘late’ – for example, ‘early spring’, ‘mid-spring’ and ‘late spring’. If you find it helps, these 12 divisions of the year can be applied to the appropriate calendar months in your area.
PLANT NAMES
Currently recommended botanical names for plants are given throughout this book. Where earlier and perhaps better-known botanical names are still used, however, these are included so that you will instantly know the plants being discussed. Common names for plants are also given.
GETTING STARTED
Philosophy of raising plants
What are the keys to success?
Whatever the method you use to increase plants, it is essential when raising them vegetatively (for example, from cuttings and by division) that ‘mother plants’ are free from pests and diseases, as well as viruses. They should also be good examples of the species being increased. When buying seeds, ensure that they are properly labelled and not excessively old (for most species, the ability to germinate diminishes with increasing age – see page 9).
HELPING NATURE?
Many methods of increasing plants, such as sowing seeds or layering, are only extensions of nature’s way to increase plants. Budding and grafting are seldom seen in nature, although stems and branches sometimes rub against each other and become united – but this is a rarity.
When raising plants by seeds sown outdoors, be guided by the weather and the natural cycle of the seasons; it is no good sowing seeds if soil is hard and impervious, saturated with frozen water, or cold and dry. The essential requirements for the germination of seeds are described on page 9.
MAIN WAYS TO INCREASE PLANTS
Seeds
This is the main way in which many plants naturally reproduce and spread themselves. Each seedling usually has the characteristics of its parents, although sometimes they slightly differ. Requirements for germination are moisture, air and warmth. Most seeds also need darkness. Plants raised from seeds (see pages 8–19) include hardy annuals, half-hardy annuals and biennials, and some herbaceous perennials can also be raised in this way.
Layering
It is one of nature’s natural ways to increase shrubs with low-growing stems (see page 33). Trees with a pendulous or low habit are further candidates, as well as some climbers. Each new plant is identical to its parent, and it is an easy and popular way to increase plants. However, rooting is not quick, and during the period of rooting it is essential to keep the soil free from weeds and moderately moist. Some plants, such as blackberries and hybrid berries, can be ‘tip-layered’ by burying the tips of shoots (see page 33).
Division
Plants with clusters of shoots at their bases, from herbaceous perennials to houseplants such as Sansevieria trifasciata (Mother-in-law’s Tongue), can be divided. Each new plant closely resembles the parent plant and because each part has roots and stems it soon becomes established (see pages 30–31).
Cuttings
This method of increasing plants produces replicas of the parent plants. Cuttings are formed from leaves, buds and roots; the most popular way is from shoots and stems. The three main forms of cuttings from shoots and stems are softwood, half-ripe (also known as semi-hardwood and semi-mature cuttings) and hardwood (see pages 20–29).
Grafting and budding
These are more complicated methods of increasing plants, and are mainly performed on plants that do not come true from seeds and cannot be divided or layered. Budding involves uniting a bud of the desired variety with a rootstock of known and desired vigour. In grafting, a shoot with several buds is united with a desired rootstock (see pages 38–41).
Wildflower meadows often become a feast of colour from annuals; wildflower mixes are available from seed companies.
Plants for easy propagation
Where do I begin?
Many plants can be easily increased by home gardeners and a wide range of them are featured here. Most techniques for increasing plants do not need expensive and complicated equipment, and some methods, such as taking hardwood cuttings, require only a sheltered piece of ground. Layering a shrub is also straightforward and requires just a few simple tools, but rooting takes many months. Grafting and budding are more complex, but still possible.
SINGLE OR MANY PLANTS?
Some methods of increasing plants, such as by seed, produce many new plants, while layering a shrub or tree creates only one new plant for each branch that