Chemical problems can often be resolved by leaching in running, or frequently changed, water. Many plants from temperate to arctic conditions have a dormancy control which is neutralised by exposure of the imbibed seed to a period of low temperature. Immature embryos can be brought up to size by the warm storage of seeds that have been kept in damp conditions to take up imbibed water. When manipulating seeds physiologically, and so preparing them for germination, it is always necessary to use an imbibed seed sample so that the normal growth processes affected can be activated. Although these dormancy conditions provide difficulties for the propagator seeking to achieve seed germination, they are, of course, very necessary to the plant to ensure its survival from generation to generation. Germination may be spread, for instance, over several years or it can be prevented from occurring until environmental conditions are better suited both to germination and seedling survival. These dormancy problems often prove difficult for the gardener to overcome, either because of the small quantities of seed to be treated or the complexities of the treatments themselves. The only feasible alternative lies in the possibility of avoiding dormancy. This will normally involve the collection of seed while it is still "green"-at a stage when embryo development and food storage have been completed but before any intractable dormancy conditions develop, usually during the drying phase before dispersal. To propagate plants vegetatively, material must be produced in a highly vegetative condition. The normal method of survival employed by most plants is to produce seeds and a natural ability to propagate vegetatively is not, therefore, a high priority. The propagator must, therefore, attempt to determine those aspects of "vegetativeness" in the plant which might enhance asexual propagation, so providing a high capacity to regenerate, and subsequently try to encourage the development of this condition in the parent plant. In the life of a plant there are three stages-juvenility, maturity and senility. In the juvenile stage (i.e. before sexual maturity and an ability to flower is developed) it is easy to show that the plant has a high capacity to regenerate vegetatively, as layers or cuttings can be rooted quickly. However, once a plant reaches maturity and is capable of flowering this ability declines dramatically, and continues to decline with age. It is, therefore, reasonable to suggest that the physiological conditions associated with flowering depress regenerative capacity. Thus, if the metabolism could be influenced so that the flowering process is suppressed, it could be expected that the plant would be stimulated towards an increased ability to regenerate. This is achieved by hard pruning which encourages the development of vegetative non-flowering material in stems; and as, in practice, "vegetative" growth is rapid and vigorous, the same principle can be applied to root generation.