APRIL. 
Ill 
saved from disease and death (as well as the crop) by timely covering, 
it certainly is well to do so, but it must not be forgotten that trees 
growing in very wet soils, and the branches overcharged with corrupted 
sap, are less able to resist injury by frost than those growing in dry 
soils; although the Peach is liable to the disease, in the latter case 
it does not often prove fatal. 
In regard to using covering, and applying it in a way to injure the 
crop, this happens when it is placed on them before the blooms expand, 
and it remains till the trees are in full leaf. Protecting fruit-trees in 
this manner, if the covering is closer than a herring net, always tends 
to do more harm than good in saving the crop—indeed, it sometimes 
happens that not a single fruit will set under such circumstances, when 
the blossoms are partially excluded from the two great agents in the 
setting of stone fruit, viz., air and light. 
The foregoing remarks go to show, in the first place, that covering is 
requisite to the health and longevity of the trees; and secondly, that it 
is injurious to the crop when allowed to remain on the trees through 
the daytime. Now, to ensure a crop and keep the trees in health, the 
covering ought to be of a texture sufficient to resist 5° of frost, and 
applied in a manner so that it may be easily removed every day, and 
it matters not what plan is adopted as long as this end be attained. 
But the saving of labour is a thing to be aimed at in all garden 
appendages, and doubtless the best and most simple way of covering 
wall-trees is to have the blinds fixed on rollers similar to window- 
blinds, so that they may be drawn up and down at pleasure; if the walls 
are low, curtains, with rings running on a rod at the top of the wall, 
will answer well. 
J. Powell. 
THE VINE MILDEW—ITS CAUSE, &c. 
It does appear anomalous at the present time, when so much has 
been written respecting the Vine mildew, to find that its habits and 
mode of propagation are now only partially understood. We hear one 
person seriously stating it, “ As his opinion that the malady springs 
from the root; ” another states, I suppose seriously (?) “ That there 
\vas no difficulty in stating the cause to be extreme dryness—the 
Vines required water” (at the roots), and in another instance a con¬ 
taminated atmosphere was the cause of mildew. I should suppose 
there are few, who, after a moment’s reflection, would be willing to 
admit such principles. But cleanliness, strict attention to free and 
judicious ventilation, as well as to the state of the roots, &c., is abso¬ 
lutely necessary in order to obta in success ; and I am also fully 
convinced that plants suffering from any ot the above requisites is more 
susceptible of disease than when properly attended to ; but by no means 
can I admit that any one or all of the evils combined would cause mildew, 
neither can I admit the theory of your correspondent “ H.B ” in last 
month’s Florist, “ That a young plant will bear a greater amount of 
drought, without injury, than one approaching maturity.” In the case 
of young Vines, the roots would be less extended through the soil, while 
