ON THE EXPOSURE OF PLANTS. 127 



winter. And instead of the slow and sturdy growth which would 

 have happened to a plant on a dry and breezy hill, or on a northern 

 aspect, we have an enfeebled nursling, unfit to bear the rigours of our 

 climate from sheer mismanagement. 



Many proofs of the truth of these statements may be adduced, but 

 we presume they are unnecessary, as the facts must have been repeat- 

 edly observed by our readers in general. The fact, however, is most 

 important, not altogether for the sake of naturalising exotic plants, 

 but for fixing the sites for gardens and orchards, which, if misplaced 

 at first, give cause ever after for regret. 



Not only do the exhalations from a moist valley generate cold, but 

 the cold air which descends upon the hills after sunset is said to 

 " slide down " and settle in the lowest place. So firmly is this 

 believed and acted on by a well-known horticultural philosopher, 

 John Williams, Esq., of Pitmaston, near Worcester, that in all cases 

 where a garden is made on ground sloping to the south, that gen- 

 tleman invariably advises the lowest boundary to be a hedge; or, if 

 a wall, it be raised on grated arches high enough to allow the escape 

 of the cold fleece of air accumulated within the garden. On the same 

 principle, whatever may be the aspect, the upper boundary wall 

 should be high and close, to intercept the descending current and 

 divert it round the ends. 



From these circumstances, then, it is fair to conclude that low 

 situations should never be chosen for garden sites, or as the best 

 places for tender exotics. 



There is another circumstance not yet adverted to which operates 

 injuriously on tender plants in sunny and sheltered valleys. There, 

 they are sooner affected by the returning warmth and solar beams of 

 spring, and hurried into a premature growth long before frosts are 

 over, or the summer temperature confirmed. They are awake and 

 putting forth their tender leaves and shoots before the exposed resi- 

 dents of the hill are in the least acted on. The first have their sap 

 liquefied and in motion; that of the second is clammy and at rest; 

 the first suffer because they have to sustain four degrees of frost per- 

 haps, when least prepared for it, while the second have only to bear 

 two degrees, and are otherwise fortified against it. 



The native plants of the frosty regions of Siberia suffer greatly 

 from late frosts when introduced into British gardens, not from the 



