894 



PRACXrCE OF GARDENING. 



Part III. 



of the climate Is kept up by a constant evaporation from swamps, rivers, and lakes, the 

 largest in the world. As we cannot have the mitigated warmth of the climate of South 

 America in plantations, in the full ground, and as the temperature of our winter cannot 

 be expected to coincide in its effects with the corresponding season even of North America, 

 when so many local circumstances are different, it is neither indispensable, nor perhaps 

 advisable, to create an artificial swamp for the cultivation of many American plants. It 

 is mostly safer to confine the efforts of imitation to the kind of earth, unless the water 

 can be carried off at any time ; for the lodgment of wet might cause some kinds of roots 

 to perish in cold weather. Thus the andromeda arborea would be injured by being floated 

 in winter, and must be protected from frost, though it requires a deal of water in summer. 

 The great object is to imitate the American peat. This is a composition of the branches, 

 twigs, leaves, and roots of trees, with small plants, grass, and weeds ; by having lain 

 immemorially in water, the whole is formed into a soft mass, and, when the materials 

 are completely decayed and blended so as to be homogeneous in appearance, the com- 

 pound is the finest vegetable mould : where this description of peat cannot be obtained, 

 recourse m.ust be had to the best that can be procured from marshes, bogs, or heathy 

 commons, which must be well turned and sweetened, and mixed with sand and rotten 

 leaves or dung. " The soil being procured, the next thing to be done is to form a stratum 

 of it of sufficient thickness in the site intended for the plants. When they are merely 

 to remain a year or two, this need not be above a foot in depth ; but where tliey are to 

 remain peraianently, it should be at least three feet thick. To encourage the roots to 

 penetrate the native soil, the bottom of the excavation should be dug and mixed with 

 peat ; imlcss a bottom of rough gmvel were substituted at the depth of four feet, and 

 such an arrangement made, as that water could be introduced to, and withdrawn from, 

 this layer of gravel at pleasure, so as to saturate the whole superstratum of peat. In level 

 situations, and where water was abundant, this plan might be readily adopted, and none 

 could more closely imitate nature, as, by keeping the surface of the peat a few inches 

 below the level of the natural ground, the water might be allowed to rise a few inches 

 above the peat, and inundate the whole surface of the American ground. In peat coun- 

 tries, and where the climate is moist, as in Lancashire and Cheshire, admirable contri- 

 vances of this kind might be adopted, and the American and bog-earth plants, herbaceous 

 as well as shrubby, grown to the greatest perfection. 



6569. Final situation. American and peat-earth shrubs, reqiuring large masses of their 

 peculiar soil, and frequent artificial waterings, cannot conveniently be introduced in 

 mingled borders or shrubberies. They ai-e therefore generally planted by themselves in 

 beds or compartments of peat-earth ; or entire gardens or shrubberies are devoted ex- 

 clusively to them. This last mode appears decidedly the best, as the general habits and 

 appearance of American peat-earth plants, independently of their culture, do not har- 

 monise remarkably w-ell with European species. An American garden may have a 

 northern or eastern exposure, and if it slopes considerably will be still less affected by 

 tlie warm dry weather of summer. It may be laid out in any of the different styles of 

 flowei-garden {^jigs. 541. to 545.) ; herbaceous plants introduced as well as shrubs, and 

 the whole surrounded by a sloping phalanx of American trees. The sorts may either be 

 arranged in the mingled manner (61vS9.), or grouped or classed according to some system. 

 (6141. to 6150.) Many and indeed most of the American shrubs thrive under the partial 

 shade of lofty deciduous trees, and the leaves which fall from these protect their roots 

 both from the frosts of winter and the drought of summer, while they constantly decay 

 into vegetable mould, and thus at the same time affords supply of nourishment. Hence, 

 in some cases, the hardier sorts of rhododendron, azalea, andromeda, &c. may be intro- 

 duced as undergrowths in the margins of thin woods, placing under each plant a cubic 

 yard or more of its pi'oper soil. This mode of planting, it would appear {Mason on 

 Design, art. Fitt), was first adopted by the great Earl of Chatham ; but it has been car- 

 ried to the greatest extent, not only with American plants, but with roses and other 

 tender shrubs, in the extensive woods of Fontliill, where, as also at King's Weston near 

 Bristol, Kenwood at Hampstead, &c. many of the plants shed their seeds, and young 

 rhododendrons and azaleas spring up in abundance. In the nurseries, it is a general 

 practice to keep American and other peat-earth plants in pots, and to protect them during 

 winter in frames and pits for conveniency of deportation. At the Hammersmith nursery, 

 one green-house is exclusively devoted to evergreen magnolias. All the American and 

 peat-earth shrubs may be selected from the three first tables in next section, by observing 

 the indication of peat-soil (letter p) ; and the herbaceous peat-earth plants may be selected 

 from the tables of Border- Flowers in a similar manner^ 



