AUTUMN COLOURS 



There is a certain amount of mystery about the 

 autumn colouring of the foliage of hardy trees and 

 shrubs in this country, and we have never yet ascer- 

 tained with any degree of exactness the conditions 

 that produce the richest and brightest colours. 

 Probably the conditions most favourable generally 

 are provided by a good growing season — that is, a 

 warm, moist summer — followed by a dry, sunny 

 autumn. But it frequently happens after what one 

 would regard as favourable seasons, that species 

 which are usually quite trustworthy in this matter 

 fail to colour well. Probably one set of condi- 

 tions does not suit all trees and shrubs in this 

 respect. To produce the colouration of the leaf 

 just before it falls certain subtle chemical changes 

 in its composition take place. And to bring about 

 these changes certain conditions in regard to sun- 

 light, temperature, and moisture are necessary. But 

 in a climate such as that of Britain, where the 

 seasons are never alike two years together, we can 

 never hope to obtain the same regularity of autumnal 

 colouring that characterises the vegetation, for in- 

 stance, of the Eastern United States. Still, when 

 all is said, we possess in our gardens a large number 



of trees and shrubs and climbers that are delightful 



63 



