Even at Upsala, latitude 59 deg. 51' N., in the Botanic Garden, it
merely requires the shelter of a few branches to protect it in the
winter; but this hardiness may be accounted for by several physiological
reasons. Like all fruticulose labiates which have a hard compact tissue
and contain much oily matter, the lavender absorbs less moisture than
herbs which are soft and spongy, and, as it always prefers a dry
calcareous, even stony, soil, the northern cultivators find that by
selecting such localities the tissues of the plant take up so little
water that the frost does not injure them.
In a northern climate the length of the days in summer, and the natural
dryness of the air, compensate in some measure the reduction of
temperature, and mature the plant only to the extent sufficient for the
purpose for which it is grown. Perhaps the suspension of vital action
during winter, which must be more complete in northern latitudes, as our
frosts are more severe, tends to preserve certain plants, native of the
south, for it is observed that all plants are more sensitive to cold
when vegetation is active than when it is at rest.
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