April 24, 1884. ] 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
319 
of this or aphides appearing •while the plants are growing 
vigorously. 
When well ripened in autumn they should be taken down 
from under the roof and five strong stakes placed at equal 
distances round the sides of the pots, the growths trained round 
them, and then stood outside until the approach of sharp 
weather. This further ripens, and is the means of inducing 
them to rest early, which is the secret of success, for they wiil 
start eai’lier and better into growth afterwards. If the blooms 
are wanted for cutting the system of training given is the best, 
for they will break from every eye along the shoot. 
When the plants are raised for the express purpose of plant¬ 
ing out it is best done while they are in active growth, in fact 
when ready for placing in their pots. By planting when in 
this condition they get well established before the winter, which 
is important, in order to secure a strong and vigorous growth 
the following year. The Marechal being such a free-floweiung 
Rose the young plants should not be allowed to carry the 
quantity they will produce the following spring after planting, 
the whole if possible should be removed, which will be found 
to be very beneficial to them. The quantity of flowers they will 
carry if allowed to remain exhausts the plants to a much greater 
extent than many suppose. 
Pruning can be conducted on two principles, but the one 
by which the greatest quantity of bloom can be obtained should 
be practised. All the strong growths that issue from the base 
of the previous year’s wood should be retained and laid in, 
while some of the weaker shoots can be shortened or cut out 
to make room for them. The side shoots or twiggy growth 
may, if likely to become crowded, be cut out or shortened back 
to one joint. The very weakest shoots are taken out, while 
others are only shortened back or thinned. Under this system 
of pruning more blooms will be produced than would be the 
case if the plants were cut hard back and had to produce again 
long strong shoots to fill the space. This plan need only be 
adopted if large flowers are required in preference to a greater 
number.— Wm. Bardney. 
PETROLEUM AND ITS USES. 
Although so much has been written on this as to its value in 
horticulture there are many who have not commenced using it, and, 
on the other hand, there are others who have long since discarded it 
and taken up other more expensive and less effectual insecticides, 
simply through accidents occasioned by the paraffin being injudiciously 
applied. Great care is necessary in the preparation previous to its 
being used on tender plants, as without this success is very uncertain. 
I have used it now for several years successfully on many stove and 
greenhouse plants, such as Crotons, Dracaenas, Gardenias, Stephanotb, 
Azaleas, and Camellias, and therefore I am in a position to say it is 
a safe and effectual remedy against mealy bug, scale of all kinds, and 
thrips. I cannot assert it is destructive to red spider, and it is of but 
little value for aphides, at least such is my experience ; but there are 
other very simple means for the destruction of these pests. 
In the first place water heated to 110°, or as hot as the operator 
can bear it, should be used, as at this temperature the oil mixes better, 
and it will also be more effectual. Two ounces to a gallon is con¬ 
sidered sufficient for most of the insects above mentioned ; and in 
measuring, for want of something better, we have an ordinary 
6-oz. medicine bottle, using this filled for four gallons of water. 
Two syringes are set to work, and after the whole has been thoroughly 
mixed by forcibly discharging the contents of the syringe into the 
vessel used for the purpose several times, one man then commences to 
syringe the affected plants with the mixture, while the other con¬ 
tinues stirring the contents of the pot with all the force possible, 
otherwise the oil floats on the surface. Where one syringe only is 
available every third syringeful should be applied to the plants. 
Some use soft soap with the oil, but, after trying both ways, I fail to 
see any advantage from using the former substance when the latter is 
sufficient by itself. Dull weather should be selected for applying 
petroleum, or in the evening after the sun is off the house, as I have 
found the sun affects the oil in such a way as to be very injurious to 
plant life. It is the safest plan to wash the oil off with ciear water 
some time after, although in dull weather we have frequently left this 
on them without any apparent harm. In mild weather we carry our 
plants outdoors and lay them on their sides to clear them, as in this 
way any insects that fall off uninjured can be left outside. 
As a winter dressing for Peaches the trees here have received 
nothing more than this for several years, and we are never troubled 
with either scale or bug now. Care is taken to wet every part of the 
tree, and this is cairied out in the same manner as in the case of 
plants. The time taken in applying this on Peach trees is very little 
compared with the old system of brushing all the maiu stems of trees 
with various other mixtures, not to mention the fact of its being so 
much more effectual, while several of the latter are equally as 
dangerous if not applied carefully. 
Climbers such as Stephanotis, Thunbergias, Tacsonias, and 
Passiflora, when affected with mealy bug, we look over frequently, 
applying a mixture of water and p uaffiu in about equal parts with a 
feather ; a touch from the tip of the latter dipped in this proves 
instant death to this pest, and by adopting this plan we can keep free 
from this much-dreaded insect. For sponging, too, paraffin is in 
request, this leaving more easily the desirable and beautiful gloss on 
the leaves, and also causes the dirt to separate more easily ; but in 
this case soap is used with it, the former in the proportion of about 
a teaspoonful to a gallon of water, care being exercised to stir it well, 
so as to avoid taking the oil from the surface in the sponge. 
If petroleum of good quality is obtained, and strict measures 
taken in its preparation, no one will have occasion to abuse it, as on 
these two points success depends. We use it here for cleaning the 
glass and woodwork of the houses, and find iLmore speedy in its 
action than soap alone. 
In the fruit garden petroleum is indispensable, many gardeners 
using this for soaking various kinds of seeds to protect them from 
the attacks of birds and mice ; but we find it is not proof against the 
latter by itself, but if a little red lead is shaken over the seeds when 
wet they will not suit their tastes so well. It is thought by some that 
the Celery and Onion flies can be partially checked by syringing this 
over the plants occasionally in the evening, and for American blight 
on Apple trees it is a well-known remedy, as well as for the scale that 
infests Pear trees.—A Young Gardener. 
THREE PRETTY COOL HOUSE PRIMULAS. 
Primula obconica —known also as P. poculiformis—may be 
allowed to head the list, for it is so charming and floriferons; 
indeed, when once it commences flowering it is difficult to say 
when it will stop. I have had a plant in flower since last 
October, and it looks as if it would continue until next October, 
and it is now crowded with large heads of pale lilac flowers, each 
about three-quarters of an inch across. We are indebted to 
Messrs. Yeitch for its introduction, and the Journal was the 
first to publish an engraving of it. It is not difficult to predict 
a happy future for the plant, as it is so easily grown, and gives 
an excellent display, far more than compensates for the small 
amount of trouble incurred in securing good plants. The plant 
referred to above was one of a batch rais d from seed last March 
in a cool greenhouse, and grown through the summer in a similar 
house. 1 am now about to sow a fresh batch of seed, with the 
idea of procuring plants for next winter’s flowering, and the 
seed will be treated very much like that of the Chinese Primrose, 
using well-drained pots filled with light sandy soil. Well water 
the latter before sowing, strew the seed thinly on the surface 
and sprinkle a little sand over it, cover the pot with a sheet of 
glass, and place it on a warm shelf in the greenhouse. When 
the young plants are large enough they should be potted singly 
in thimble pots, and afterwards treated like the Chinese Primrose. 
It is a native of Japan. 
Primula floribunda is a little-known gem well deserving its 
name, for it is impossible to possess a plant which flowers more 
freely. Commencing in a cool house in September or October it 
will continue nearly to the same months of the following year 
unless prevented, which is advisable, or the plants will quite 
exhaust themselves ; and if the blooming is thus stopped the 
plants may be shaken out, repotted, and grown freely, as I believe 
this species is nearly a perennial. I have some plants in their 
third year, and they are now full of flowers. The latter are bright 
canary-yellow, about half an inch across, arranged in whorls 
similar to P. japonica, but the rows are not so numerous as in 
that species. It seeds very freely, and there is no difficulty in 
obtaining a large stock. They are easily raised in a cool house. 
They are very small, and consequently must only be lightly 
covered. The foliage is very hairy, and liable to decay if con¬ 
stantly wetted, hence it is necessary to avoid doing so. It is a 
charming little plant for arranging with small Ferns, very dwarf 
in habit; my tallest plants are not more than 9 inches high. 
P. verticillata.—This species is better known, but very much 
less cultivated than it should be, as it is so pretty during the 
early spring months, producing good trusses of sweetly scented 
bright yellow flowers, with white powdery calyces and footstalks, 
which are in happy contrast with each other ; the leaves are also 
thickly coated with white powder, and the whole plant has a very 
distinct, and, to my mind, beautiful appearance. All such plants 
deserve to be more generally cultivated. I do not wish to recom¬ 
mend the culture of weedy plants, but there are many looked 
upon with a suspicious eye by gardeners, which would really 
