12 
CULTIVATION OF TENDER EXOTICS IN THE OPEN AIR. 
litter thrown over their roots and the lower parts of their stems, or a mat cast 
loosely around them, in the severest weather. 
As it will be exceedingly easy in most places to alter every border of the sort 
that happens to be possessed, according to the rules now to be suggested, we shall 
state what, from extensive examination, appears to us to be the best dimensions, 
height, and mode of preparing snch a border. If the trouble which the adoption 
our hints will cause should form a ground of objection, a comparison between this 
and what would be necessary if the same species were grown in pots in the green- 
house, will at once show which is the lightest. 
At the basis of all attempts of the kind, must be a proper provision for obtaining 
all the shelter which the wall or structure will afford ; for receiving the greatest 
amount of heat which can be diffused from it, supposing it to need the employment 
of a fire apparatus ; and for maintaining it in the autumn and winter, or throughout 
entire seasons that are extremely wet, at a tolerable degree of dryness. These 
precautions cannot be overlooked without more or less diminishing the safety of the 
system. 
To notice them specifically : — In order to ensure a sufficiency of protection from 
the wall or house, they must, on no account, be below the ordinary height. From 
ten to twelve feet, or more, seems indispensable for this purpose. It is desirable, 
too, that they should not occupy an elevated position ; otherwise their usefulness 
would be lessened by the current of cold air which would frequently surround 
them. For a like reason, if shrubberies, or any erections, stand at a slight distance 
from them on the eastern side, so as to exclude the keen winds which often blow 
from that quarter, another important point will be gained. 
With the combined object of attaining the condition named in the preceding 
paragraph, and that of having whatever heat escapes from the house carried as far 
as practicable through the whole of the border, the latter should never be much 
more than four feet broad. A width of six or eight feet would take the plants 
placed near its front beyond the protection of the wall, and also remove them from 
the agency of the heat given off by the fire used behind or within. Nearly all 
plant-structures have, or ought to have, their flues or pipes which convey the heat 
through them, arranged along the front, and only a short distance from the ground. 
Where much fire-heat is wanted, and even when it is required solely in bad 
weather, some of it must necessarily pass through the front wall, so that at least a 
trifling amount of its influence will be experienced in the border. This will not be 
of service in warming it, nor can it in any way materially affect its temperature ; 
still it is not a warm but a dry soil that is so desirable in winter, and the most 
trivial assistance of such a sort will be very sensibly useful. 
In houses where fires are only occasionally requisite, and the means of heating 
them are fully adequate, it would be highly advisable to leave small apertures in 
the front wall, whereby the internal temperature might, to some slight extent, be 
communicated to the outer border, and so be iifistrumental in dispelling part of its 
