HARDY AND HALF-HARDY ANNUALS. 
167 
is injurious, in a greater or less degree, by 
preventing the leaves from performing their 
proper office. Sulphur is sometimes applied 
as a remedy, but it is in many points objec- 
tionable ; and its efficacy, at least, in out-of- 
door application, is highly questionable. Pre- 
vention is far easier and safer than any means 
of cure. Sometimes the trees are attacked by 
one or two species of Aphides ; but they are 
far less liable to the attacks of these insects 
than many other trees : the infested parts 
should be removed, or they may be pressed 
between the fingers, so as to crush the insects, 
and then be submitted to a cleansing by pure 
water from the engine. 
The principal diseases which attack the 
Peach-tree are the mildew, the gum, and the 
canker, under each of which names it is 
probable that many varieties of infection are 
included. As the attacks of insects arise 
chiefly from neglect of the plants themselves, 
so do the diseases to which they are subject 
arise, in a great degree, also from neglect ; 
but, in this case, it is the conditions of growth 
which are not sufficiently attended to. Almost 
all diseases originate in the soil ; or, in other 
words, it is the condition of the soil which 
renders the plants Liable to the attacks of 
disease. Thus of the mildew, which is itself 
a parasitical fungus, growing on the live plant ; 
it is the joint influence of too deep and too 
rich, or too moist a soil, aided by sudden 
changes, or unfavourable conditions of the 
atmosphere, which produce the circumstances 
that are favourable to the growth of mildew. 
Microscopical observations made by men of 
great talent and ingenuity, leave no doubt of 
the mildew being a fungus :. but still the 
question remains, — where does this- plant 
come from ? No rational mind, with the 
evidence of the whole visible and material 
world about him, can believe that they spring 
of themselves p and it is, therefore, more 
rational to suppose (since we know, by the 
example of the common puff-ball, and others, 
that the reproductive atoms of fungi are 
minute and buoyant) that the germs of the 
mildew parasite, which is of quick growth, 
and soon bursts and disperses its sporules, are 
wafted in the atmosphere, and are lodged in 
many a situation as they may chance to be 
obstructed in their progress, but germinate 
only in those cases where they reach a medium 
which is suitable for their development. To 
place the mildew to the account of some evil 
in the border will not, therefore, be difficult. 
The leaves being too abundantly supplied from 
the roots, with the elements of their nutrition, 
which exist too plentifully in the border, and 
being excited into vigorous action by increased 
heat in the atmosphere, are suddenly checked 
in the exercise of their functions by a rapid 
fall of temperature, a decrease of light, or a 
change in the condition of the atmosphere : 
the roots not being subjected to the same 
influences, in any proportionate degree, con- 
tinue in a vigorous state of action ; and the 
sap, not being subjected to its proper elabora- 
tion in the leaves, finds a vent through their 
pores ; here, on the surface of the leaf, it 
stagnates, and becomes morbid, and, in this 
condition, it appears to be highly favourable 
to the germination and growth of the fungus. 
This, however, is speculation, and speculative 
the subject must remain, since in these minute 
and mysterious matters we can scarcely 
arrive at ocular demonstration. Sulphur has 
been recommended as a cure for mildew ; but 
its chief use would appear to be its action as 
an absorbent, and it, therefore, can have little 
influence on the disease itself : this should be 
prevented by attention, to the method recom- 
mended in the construction of the borders ; 
and it would seem to be removed from the 
plant, by the unflinching use of the engine at 
such times as the weather will admit of the 
leaves soon becoming dry after the application 
of the water. 
The gum and the canker are also, without 
doubt, occasioned by the access of the roots 
to a large quantity of crude matter, which 
is absorbed by them, and conveyed to the 
branches. The canker, indeed, appears to be 
almost identical with the eruptions occurring 
on the leaves, and may, perhaps,, be regarded 
as a more deeply-seated form of the same 
kind of disease. The exudation of gum is, 
doubtless, dependent on some abstruse che- 
mical action, into which it would be unin- 
teresting in this place to inquire. Certainly 
they both arise from repletion ; and the suc- 
cess of any methods of cure will depend more 
on the use of proper regimen, than on the 
employment of any external and superficial 
applications. .] 
THE CULTIVATION OF HARDY AND 
HALF-HARDY ANNUALS.. 
Annuals are among the most useful of 
flowering plants to the small gardener ; useful, 
because they speedily produce a return for 
his labours, and that return but little,, if any, 
behind in beauty the very choicest of Flora's 
gems. The blaze of beauty required in the 
gardens of aristocracy, could not be kept up 
without the aid of annuals ; and no other race 
of plants is so well adapted to decorate the 
parterre of the cottage, because no other race 
calls for less of sedulous and officious care. 
Annuals suitable for flowering in the open 
air, may be conveniently divided into two 
classes ; viz. hardy and half-hardy. 
