ON THE DAHLIA. 
269 
Upon such a tract of country, the action of the weather is very 
severe ; and it is, in all probability, increased by the great elec¬ 
tric tension of the atmosphere, which is more intense and variable 
in such climates than in any others. The result is a great disin¬ 
tegration of the rocks ; and this, with the absence of deciduous 
leaves and the paucity of surface vegetation, causes the soil to 
contain an excess of sand, or decomposed stone, which makes it 
loose and porous. This is exactly the soil which suits the Dahlia; 
and they who wish to have plants, not overgrown, but in fine con¬ 
dition for blooming, imitate this soil as nearly as possible, and 
bring it to such a consistency, as that the water may not stagnate 
and soak the roots, or bind an adhesive soil too closely about them. 
Dahlias will grow even more vigorously in the individual plant in 
rich and somewhat adhesive soils, than in such as are light and 
porous ; but the flowering is always inferior, and the stems are 
tender, and sooner injured by the wind or by cold, than in the 
case of smaller plants, which grow in more appropriate soils. 
Perhaps all plants are improved by having the soil in which they 
are cultivated a little richer than that in which they grow natu¬ 
rally ; and probably this enriching requires to be increased, when 
the plants are carried from a warmer to a colder climate ; but these 
are points which can be determined only by the practical cultiva¬ 
tor, and even he must be careful not to exceed the proper mea¬ 
sure. If the natural soil is very wet and retentive, an underground 
drainage becomes necessary ; and brick and lime rubbish is a 
very good material for this purpose. This drainage must be 
placed so far down, as that the roots should not reach it; but lime 
rubbish makes a good ingredient in the soil wherein the plants 
are immediately grown. This soil should not be finely pulverized, 
nor should its surface be too smooth ; but it ought to be kept as 
open as possible, in order to admit the rain to drain off, and air 
and heat to have access to the roots. This is essential to the suc¬ 
cessful growth of plants which have large fleshy roots ; for if these 
are cramped, and not properly stimulated, the growth of the plants, 
and especially the flowering, are always inferior. 
In their native country, Dahlias hybernate or take their repose 
in the ground ; but that plan does not answer even in the most 
favourable soils in this country. If the crowns of the roots are 
too near the surface, they are in danger of being killed by frost; 
and if they are too deep for being hurt in this way, they are liable 
