The Principles of Gardening: A Guide to the Art, History, Science, and Practice of Gardening

`Principles of Gardening' by Englishman Hugh Johnson is one of those rare and sometimes hard to find exceptional books on a subject which every enthusiast for an avocation looks for and often does not find. Almost all academic subjects have these `magic' volumes such as Snedecor and Cocheran's `Statistical Methods' for basic statistics and Willard Van Ornim Quine's book on modern introductory symbolic logic. Many practical pursuits I know well also have these `great books'. Cooking, for example, has Harold McGee's `On Food and Cooking' for the theoretically minded and Julia Child's `Mastering the Art of French Cooking' for the more traditional. While many of the practical pursuits are enhanced by reading their scientific underpinnings, it is a mistake to assume that one cannot advance one's knowledge and excellence in practical matters without studying their science. In cooking, both practice, practical experience, and the senses are at least as important as `understanding' provided by scientific knowledge. One can know that lemon juice and vinegar are often interchangeable without any knowledge of the pH scale of acids and bases. Similarly, one can appreciate that impatiens likes shade while pansies like sun without knowing much about photosynthesis or growth enzymes. And yet, sound scientific knowledge can often take one further faster than mere practical experience, especially for someone just starting out who already has a good basis in physical sciences. Another virtue of scientific understanding, which it shares with historical knowledge, is that both simply make a subject more interesting and more enjoyable for the enthusiast. This is actually more important for gardening than it is for cooking, since most people have to live through three to five months of gray dormancy while waiting for the return of Spring. The greatness of Hugh Johnson's book lies less in it's subtitle, `The Practice of the Gardener's Art' than it does in explaining the major topics of gardening to the winter armchair garden daydreamer. And, while this essay does include a lot of science, it is a very gentle science very much in tune with the sensibilities of the amateur naturalist rather than the high tech lab of the modern biochemist. And, the science is so well presented that I would offer this book to even a total non-gardener if they happen to be looking for the way in which modern biological theory based on Darwin's theory of evolution is successfully applied every day to make better tulips, peas, and azaleas. The science starts with absolutely the most natural point, with the weather which to foodies is known as `terroir. If this seems obvious, I offer the fact that so simple a matter as two tulips just six feet apart bloom weeks apart due to subtle variations in microclimates due to differences in hours of sunlight they each receive in a day. The next chapter mixes history with science in covering how humans propagate plants. The third chapter adds more hist