424 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ November 19,1891. 
days before using them, where they will be guarded from cold 
draughts, yet receive enough air to harden and render both leaves 
and flowers less fragile.— H. Dunkin. 
SULPHATE OF COPPER MIXTURE AND THE 
POTATO DISEASE. 
In view of the discussion which has arisen regarding the appli¬ 
cation of the sulphate of copper mixture to prevent the spread of 
Potato disease, I take the liberty of mentioning that I applied the 
3 per cent, solution of sulphate of copper mixed with an equal 
weight of lime, as per usual directions, to a field of Potatoes 
(Maincrop and Bruce) about the end of August. Soon after I 
observed the leaves becoming spotted. Fortunately, there is little 
disease here among late sorts, and my 1891 experience therefore 
hardly counts in showing how profitable the remedy may be in a 
more unfavourable season. A small plot of Early Puritans, badly 
affected in the tops, was dressed at the same time. These were 
afterwards lifted quite sound. 
One portion of the Maincrops had been accidentally dressed 
with a large excess of lime, so much as to cause them to appear 
from a distance almost white ; and I was surprised that, though 
the leaves over the rest of the ground died away during the early 
part of October, this part remained green until killed by frost on 
the night of the 29th October, and the crop on it is unusually 
heavy. 
This curious result has led me to examine the history of the 
remedy, and I find that in the first instance some French experi¬ 
menter discovered that sulphate of copper would cure an attack of 
fungus on Yine leaves. This fungus (Peronospora viticola) is 
quite similar in its habits of growth to that familiar to us as 
Potato disease (Peronospora infestans). It is now about seven 
•years since sulphate of copper was first applied to the treatment 
of Yine mildew, and a great many experiments with regard to the 
best mode of application has been made. I venture to summarise 
some of the conclusions already arrived at from M. Yermorel’s 
pamphlet, “ Resume Pratique des Traitements du Mildiou,” as it 
is from the Yine-grower’s experience that it was first successfully 
applied by Potato growers in France. 
“ Some varieties noticed in America as disease resisting are 
attacked by it in France, and vice versa." “ As a rule, people have 
been in too great a hurry to pronounce certain kinds safe, or certa n 
remedies sure, because they were efficacious against mild attacks.’’ 
- “ The Yines of a kind least susceptible of disease have sometimes 
been seen quite covered with mildew.” “ As atmospheric condi¬ 
tions vary greatly from one year to another, a variety attacked one 
year will not be, ipso facto, attacked the following year, whilst a 
Yine that has hitherto escaped may be so.” 
Sulphate of copper alone in solutions stronger than half per 
cent, was found to burn the leaves, and M. Millardet found that 
the injury was not always in proportion to the strength of the 
solution. This latter conclusion has led to experiment regarding 
some substance to mix with the sulphate of copper, and it was 
found that if an alkali were added the burning action would be 
prevented ; ultimately lime has been generally adopted to mix with 
the sulphate of copper. It is cheap, easily procurable, and has a 
small value of its own as a disease preventive. The effect of 
adding the lime may be chemically stated as causing a double 
decomposition. The sulphate of copper is changed into hydrated 
oxide of copper (pale blue colour), and part of the lime is changed 
into sulphate of lime or gypsum. This hydrated oxide of copper is 
not very soluble, but as it adheres to the leaves is just suffkrently 
dissolved by the rain or dew to render them unfit for the germina¬ 
tion of the mildew spores. 
The formula for Potato disease recommended by the Royal 
Agricultural Society of England (20 lbs. sulphate of copper, 10 lbs. 
lime, and 100 gallons water) had been condemned by the French 
experiments, and M. Aime Girard, in bis work “Recherches sur la 
Culture de la Pomme de Terre” (Paris, 1891), mentions that in 
1890 there were some failures in treating Potato disease with this 
formula owing to the influence of the rainy season, and he states 
that it is preferable to increase the amount of the sulphate of 
copper to 30 lbs., using an equal weight of lime. 
In view of the chemical decomposition of the sulphate of 
copper it will be seen that it is essential that any labourer preparing 
the mixture for sprinkling should keep the lime well stirred, other¬ 
wise there will not be sufficient used to decompose the sulphate of 
copper, and leaves may be burned. It should also be borne in mind 
that unless the sulphate of copper and the limewash are each cold 
before being mixed some of the sulphate of copper will not be 
turned into the pale blue hydrated oxide of copper, but into the 
anhydrous oxide, which is of a dark brown colour and quite 
insoluble, so that it is useless. The sulphate of copper solution 
requires frequent stirring to keep it of uniform strength. 
It will now be apparent, if care be taken to add sufficient 
lime and the mixture properly made, the result when sprayed on 
the leaves covers them with the pale blue hydrated oxide of copper, 
with some free lime and gypsum, none of which substances are at 
all injurious to the leaves, Any cases of failure will perhaps now 
be further investigated, and those who have been affected will be 
able to secure success in future. 
From the experience of French Yine growers it seems as if our 
best course with the Potato will be to set two or three Potatoes 
of a kind we know to be weak disease resisters in the ground with 
the others, then about the middle of July give a 1) per cent, 
dressing as a precaution. These two or three sets should have 
been covered during the spraying, and if watched will afford a 
signal for a second or full dressing if disease should come. 
It may occur to some that it would be almost as well to wait 
till disease actually shows itself before using the mixture, but my 
own experience this year was that when I first noticed spots on the 
leaves there was a violent storm blowing, which lasted over a week, 
before I could use my sprinkler, and M. Girard mentions that the 
long-continued rain of July-August, 1890, in the north-east of 
France made it impracticable to apply the Bouillie Bordelaise at all 
satisfactorily for a long period, so that the only failures he knew of 
in 1890 were in that district.— Thomas Harley, Bewdley. 
CLIMBING PLANTS FOR NORTHERN 
DISTRICTS. 
Hardy climbing plants are worthy of extended cultivation, as 
it is a phase of gardening that a great majority of people could if 
they like indulge in without any very great expense or trouble, 
except the initial expense of procuring and planting suitable 
kinds. There are thousands of plots of ground at the base of 
dwelling houses and other buildings, at the foot of boundary walls, 
palli ades and palings, and various other positions which are 
admirably adapted and might be utilised, as in numerous instances 
they are, for the growing of hardy climbers. They would give, 
rightly managed, satisfaction, pleasure, and enjoyment to the 
planter or owner, and an equal amount of satisfaction, and even 
positive delight to those who might see them. There are many 
advantages accruing from the employment of decorative plants of 
this kind. When well grown, and not trained in too stiff and 
formal a manner, they are not only pleasing and ornamental, but 
obscure rough places and glaring bare frontages with either 
luxuriant foliage or bright flowers, sometimes both combined. 
There is something of effectiveness for every season of the year, 
and some—for instance, the Ivies—are effective throughout 
the year. 
In these notes I hope to succeed in making some useful remarks 
ou the hardiest of evergreen, deciduous, and flowering climbers 
which may without fear of failure be planted in unfavourable 
situations, or such as those in the immediate districts surrounding 
towns, and especially smoky and northern towns. 
Wistaria sinensis. 
First of all I will consider the claims of the Chinese Wistaria as 
a climbing plant. It is not commonly to be met with in the 
immediate districts of Sheffield, and when it is, it is generally on 
the spacious walls of old established residences in the suburbs. On 
country mansions • it is often seen to great advantage, its stout 
stems, strong shoots, and conspicuous foliage soon covering a large 
extent of space. It is one of the strongest growing climbers we 
possess, and will grow from 30 to 60 feet high in favourable posi¬ 
tions in rich, light, warm soil of a fair depth. A Wistaria and a 
Scotch Laburnum planted together produce when in flower a good 
effect, as they bloom about the same time, and the latter, though 
a flowering tree independent of any support, is yet quite amenable 
to training against a wall, where if properly treated it will flower 
freely. 
A pcsition with a south aspect is best for the Wistaria, and for 
a very lofty position it may be ranked as the best flowering climber 
that could be mentioned. Its chief drawback is its deciduous 
character in winter, but planted so, if space permits, that it c.uld 
be trained to overtop all others, the lower part of the position 
could be utilised for plants of less height, and of an evergreen 
charac'er. When not required to cover an extensive space, the 
Wistaria may be planted, and will do well in ordinary fertile soil 
enriched with manure at or before, but preferably before the time 
of planting, which may be done in autumn or spr.ng. 
After planting, and just when the topmost buds are beginning 
to start in the spring, the plant should be pruned back in order to 
secure the requisite number of branches for furnishing the space 
