62 
THE NATURALIZATION OF EXOTICS. 
also been recommended, for the superior manner in which it must naturally be 
drained; besides which, if facing the south, or any proximate point, the cold winds 
from opposite quarters are warded off by the hill itself. Any plain, however, 
occurriog on its side, is fully as appropriate, and even more so to some plants; the 
general intention being that the spot should be elevated, and not an extensive flat. 
A shallow surface-soil is the next desideratum, with a substratum of a rocky, 
gravelly, or very sandy, but by no means of a clayey or wet nature. Where both 
these are unattainable, the only substitute is a most efficient system of drainage, 
and, if practicable, the deposite of a layer of rough stony matter, about eighteen 
inches or two feet below the actual surface, to prevent the roots from penetrating 
too deeply. 
The philosophy of these provisions will be easily understood. By keeping the 
roots near the top of the ground, and guarding against superfluous water, the plants 
will be nearly as much beneath the cultivator's control, as if they were grown in 
pots. That disposition which they ever evince to become too luxuriant when the 
roots are unconfined, will be effectually checked; they will be better able to mature 
their developments ; from containing less moisture in winter, a diminished liability to 
iujury from frost will be experienced, and they will be less likely to commence 
growing prematurely in spring ; by the flowering species, blossoms will be more 
speedily produced ; and there will be a much greater chance of ripening seeds 
or fruit. 
Properly to second the above preparatives, the soil should be wholly renewed, 
if it be not precisely such as w^ould have been selected. One of the chief ingredients 
must be a fine sharp sand, and the great bulk of it may be a light friable loam, in 
which sand naturally exists. This will be seen to be far from a nutritive earth ; 
the object being rather to repress than excite exuberance of growth, and to obtain 
a medium that is not strongly retentive of fluids. 
To choose species and specimens best fitted for the purpose, the exercise of sound 
discretion is requisite. Deciduous kinds are palpably those most calculated to 
cause good results, though evergreens are unquestionably the most ornamental and 
valuable. For the former, consequently, the least attention is demanded, while 
the latter better repay the trouble they occasion. Plants of each description may, 
therefore, be indifferently selected ; simply taking care that they be sufficiently 
beautiful to merit distinction, and that, from the latitude of their native locality, 
or the height at which they are found above the level of the sea, reasonable grounds 
be afforded for believing that the experiment will issue favourably. One important 
condition is not, however, to be forgotten. When a great discrepancy exists 
between the temperature of the country in which they are wished to be naturalized, 
and that from whence they are brought, unless their habitude is dwarf, and their 
growth ascertained to be slow and easily perfected, there is a great probability of 
failure. 
Where procurable^ small seedling plants are decidedly most proper for experi- 
