590 ACCLIMATIZING OF PLANTS. 



1168. Acclimatizing of Plants. It is commonly supposed that by 

 length of time plants may be rendered fit to endure a climate which 

 they could not stand in the first instance. It has been said, that 

 by slow degrees tender plants may become acclimatized to cold 

 climates. Such a view, however, is totally inconsistent with the facts 

 of the case. Each species of plant naturally bears a certain range 

 of temperature, and it is impossible to extend that range. Many 

 plants originally placed in greenhouses, and subsequently planted 

 out, are held up as cases of acclimatization. Aucuba japonica, com- 

 ing from a warm climate, was at first treated in this country as a 

 stove-plant, and was afterwards planted out, and was found to en- 

 dure the climate, but no change was made in the constitution of the 

 plant. It was capable from the first of enduring the cold of this 

 climate. Aponogeton distachyum, an aquatic from the Cape, was 

 cultivated long in the stoves of the Edinburgh Botanical Garden. A 

 specimen was accidentally thrown into the open pond, where it has 

 continued to live and flower for many years. The constitution of the 

 plant is unaltered. It was able to bear a certain range of temperature, 

 but cultivators were not aware of this in the first instance. Plants 

 sent from warm countries, and supposed to be delicate, are often quite 

 hardy, in as much as their native locality has been high on the moun- 

 tains. Such is the case with Araucaria imbricata from Chili, and with 

 some Nipal and Japan plants. Again, take the Potato, the Dahlia, 

 Heliotrope, and Marvel of Peru, which have been long cultivated in 

 Britain, and it will be seen that they are not in the slightest degree 

 more hardy than when first introduced ; they are injured by the frost 

 just as easily as at first. 



1169. Something, however, may be done by the art of the gardener, 

 to render half-hardy species of plants less tender. In this climate, the 

 great risk in such cases, is frequently not so much the degree of cold, 

 as the accession of it at a time when the plants cannot resist it, in con- 

 sequence of being full of sap. Attention, therefore, should be paid to 

 bringing the plants into as dry a state as possible, at the beginning of 

 winter. Lindley remarks that the only means of effecting this con- 

 sists in thoroughly drained soil, and an elevated situation the first 

 preventing a plant from filling itself with moisture during winter, or 

 overgrowing itself in summer, so as to enable it to ripen its wood ; 

 and the latter securing it from the action of those early frosts in 

 autumn, or those late frosts in spring, which are so pernicious even to 

 our own wild trees. In an elevated situation, a plant also escapes the 

 risk of being stimulated into growth by a few days' warmth, succeeded 

 by nipping colds, which so often occurs in our variable climate. 



