I^'TRODUCTION. 9 



success is in proportion to the amount of practical experience 

 founded upon a scientific basis. 



Whatever causes exist to prevent the operations of gardening 

 from being carried out on scientific principles, it is nevertheless 

 true, that no methods can be generally applicable, or universal 

 in their results, that have not such principles for their bases. To 

 be guided by them, it is not necessary that the gardener should 

 be a mere reader of books, a studier of theories, or a continual 

 performer of experiments; he must add to the precepts of others 

 the acquisitions of his own experience, and aim constantly at 

 progress, by learning practically the principles upon which his 

 operations rest for their success. It is not the lot of every one 

 to discover truths hitherto unknown, but almost every one en- 

 gaged in the practice of horticulture can do something towards 

 improvement, by enforcing those already known by stronger 

 evidence, facilitating them by a clearer method, and elucidating 

 them by brighter illustrations. 



There is a wide-spread antipathy to all kinds of book instruc- 

 tion, and book gardening is ridiculed by many who call them- 

 selves gardeners. It is, nevertheless, a well ascertained fact, 

 that those who rail at book practice are not only the worst prac- 

 tical, but also the worst theorists, and the worst reasoners upon 

 matters of practical import. Indeed, there are few who are more 

 slow to recognize the benefits of the valuable knowledge to be 

 found in the works of the eminent horticulturists of this countr}'^, 

 than those by whom it is most required. ^ 



Notwithstanding the valuable works which have lately been 

 given to the world, on horticulture and the kindred arts, by 

 eminent writers, little or nothing has been done in the depart- 

 ment embraced by this treatise. Horticultural structures of all 

 kinds continue to be made, and managed, with the same disre- 

 gard to the actual habits and requirements of plants, as they 

 were a century ago. And, though some structures of this kind 

 have been constructed upon plans and principles in accordance 

 with modern knowledge, yet these are a very small exception. 

 Many apparently fine structures could be pointed to, which are 

 rendered comparatively useless for the purposes for which they 



