133 
GARDENING AS A SCIENCE. 
No. VII. 
We have already dwelt at some length upon the appropriate excellence of 
decayed tree-leaves as a manure, and it is with pleasure we perceive that their 
value begins to be appreciated. The substance of leaves comprises all the chief 
constituents of trees, shrubs, and their organic products : hence it may be safely 
inferred that it is always bad policy to remove fallen leaves from the surface of 
shrubberies during winter, inasmuch as they tend not only to form a protective 
covering, but because, having undergone a partial decay upon the ground, they 
produce dress of the best quahty when carefully forked, or digged into it, just 
before the return of spring. 
As leaves are so important during their deciiy, we are naturally led to inquire 
into their agency while growing, and endowed with the principle of life ; and here 
our attention is directed to the leading article of the Gardeners Chronicle of July 
1st, which comprises six propositions, all of great consequence, and worthy of 
profound investigation. 
"1. If all leaves which a tree will naturally form are exposed to favourable 
influences, and receive the light of a brilliant sun, all the fruit which such a plant 
will produce will ripen perfectly in a summer that is long enough." 
There is a bold assertion contained in this passage, which pointedly assails the 
entire practice of wall and espalier-training from beginning to end ; for, to say 
nothing of the amputation of at least half the laterals during the winter regulation, 
the whole course of spring and summer management comprises an unintermitting 
displacement of buds, leaves, and young shoots ; and yet we generally obtain an 
ample production of very superior fruit. Still, the theory is mainly supported by 
familiar facts : witness the utter degradation, in point of size, colour, and flavour, 
of all the fruit upon a currant and gooseberry- bush, the leaves of which have been 
devoured by the caterpillar {larva of tenthredo^ or saw-fly). But, w^hile we insist 
upon the indispensable necessity of healthy leaves — whether we regard them as 
active instruments of nutrition, or merely as organs of transpiration — it is wise 
not to attempt to prove too much. All the leaves attached to a fruit-bearing shoot 
are unquestionably vital, or, at least important to that individual member and its 
appendages ; but we may be permitted to question whether the leaves upon a 
secondary, or lateral, perform any functions beyond those essential to the shoot to 
which they are attached, or that they contribute to the general sustenance of the tree. 
" 2. If all the leaves of a tree are exposed to such influences, all its fruit will 
advance as far towards ripeness as the length of the summer will admit of ; it may 
be sour and colourless, but that condition will be perfect of its kind." 
The above is little more than a repetition of No. 1 — glancing, however, at the 
condition of winter pears, figs, &c., which remain unperfected by the sun's 
VOL. X. NO. cxv. X 
