176 
THE’ DICTIONARY OF GARDENING, 
Cacti—continued. 
when they are wintered in a moist partially-shaded house. 
During summer all the Phyllocactuses delight in plenty of 
water, and, when growing freely, a weak solution of manure 
affords them good food. Epiphyllums must be kept always 
more or less moist at the root, though, of course, when 
growing freely, they require more water than when growth 
has ceased for the year, which happens late in autumn. 
The same rule applies to Rhipsalis, none of the species of 
which are happy when kept long dry. For the several 
species of Opuntia and Echinopsis, which are sufficiently 
hardy to be cultivated on a sunny rockery out of doors, it 
will be found a wise precaution to place either a pane of 
glass or a handlight over the plants in wet autumns and 
during winter, not so much to serve as protection from 
cold as to shield them from an excess of moisture at a time 
when it would prove injurious. 
TEMPERATURE. The amount of heat required by the 
different species of Cactus varies very considerably. The 
majority of Cactuses may be kept alive in one house where 
all would be subjected to the same temperature, but many 
of the plants would merely exist, and could not possibly 
flower. It would be easy to point to several instances of 
this unsatisfactory state of things. At Kew, for example, 
owing to the arrangements pecessary for the public, it is 
found convenient to have the majority’ of the large 
collection of Cactuses in one house, where the plants 
present an imposing appearance, but where, as might be 
expected, a good number of the species very rarely produce 
flowers. \ The Cactuses which inhabit the plains of the 
Southern United States are subjected to a very high 
summer temperature, and a winter of intense cold; whilst 
on the other hand the species found in Central and South 
America do not undergo nearly so wide an extreme, the 
difference between the summer and the winter temperatures 
of these countries being generally much less marked. A 
tropical temperature for Cacti is in summer 70deg., rising 
to 90deg. with sun heat, night temperature 65deg. to 
70deg., in winter 60deg. to 65deg. Temperate: in summer 
60deg., rising to 75deg. with sun heat, night 60deg. to 
65deg., in winter 50deg. to 55deg. The hardy species 
will, of course, bear the ordinary temperatures of this 
country; but, to enable them to withstand a very cold 
winter, they must be kept as dry as possible. In the 
colder parts of England it is not advisable to leave any 
of these plants outside during winter. 
Insect Pests. Notwithstanding the thickness of skin 
characteristic of almost every one of the Cactuses, they are 
frequently attacked by various kinds of garden pests when 
under cultivation, and more especially by Mealy Bug. 
There is, of course, no difficulty in removing such insects 
from the species with few or no spines upon their stems; 
but when the plants are thickly covered with clusters of 
spines and hairs, the insects are not easily got rid of. 
For Cactuses, as well as for other plants subject to this 
most troublesome insect, various kinds of insecticide have 
been recommended; but the best, cheapest, and most 
effectual with which we are acquainted is paraffin, its 
only drawback being the injury it does to the plants when 
applied carelessly, or when not sufficiently diluted. A 
wineglassful of the oil, added to Igall. of soft water, and 
about 20z. of soft soap, the whole to be kept thoroughly 
mixed by frequently stirring it, forms a solution strong 
enough to destroy Mealy Bug. In applying this mixture, 
a syringe should be used, or, if the plants are to be 
dipped over-head, care must be taken to have the oil 
thoroughly diffused through the water, or the plant, when 
lifted out, will be covered with pure paraffin, which does 
not mix properly with water, but floats upon the 
surface if allowed to stand for a few moments. The plants 
should be laid on their sides to be syringed with the 
mixture, and after they have been thoroughly wetted, they 
may be allowed to stand for a few minutes before being 
syringed with pure water. Plants that are badly infested 
Cacti—continued. 
with Mealy Bug should be syringed with the paraffin 
mixture once a day, for about a week. It is easy to do 
serious harm to these plants by using a stronger solution 
than is here recommended, and also by not properly 
mixing the oil with the soap and water; and the 
amateur cannot, therefore, be too careful in his use of 
this excellent insecticide. 
For Scale, which sometimes infests these plants, and 
which is sometimes found upon them when wild, the 
paraffin may be used with good effect. 
Thrips attack Phyllocactus, Rhipsalis, and Epiphyllum, 
especially when the plants are grown in less shade, or in a 
higher temperature, than is good for them. Fumigation 
with tobacco, dipping in a strong solution of tobacco, or 
sponging with a mixture of soap and water, are either of 
them effectual when applied to plants infested with Thrips. 
The same may be said of Green-fly, which sometimes 
attacks the Epiphyllums. 
Hot water (140deg. Fahr.) may also be successfully 
employed against insects upon Cacti. It should be syringed 
on in the manner indicated. 
A blight, something similar to Mealy Bug, now and again 
appears on the roots of some of the species of Hchino- 
cactus and Cereus. This may be destroyed by dipping 
the whole of the roots in the mixture recommended for the 
stems when infested by Mealy Bug, and afterwards allowing 
them to stand for a few minutes immersed in pure water. 
They may then be placed where they will dry quickly, 
and finally, in a day or two, repotted into new compost, 
first removing every particle of the old soil from the roots. 
Diseases. Under artificial cultivation there are many 
conditions more or less unfavourable to the health of plants, 
and, in the case of Cactuses, very large specimens, when 
imported from their native haunts to be placed in our glass- 
houses, soon perish. At Kew, there have been, at various 
times, fine specimens of some of the largest-growing 
species, but they have never lived longer than a year or so, 
always gradually shrinking in size till, finally, owing to the 
absence of proper nourishment, and to other untoward 
conditions, they have broken down and rotted. This rotting 
of the tissue, or flesh, of these plants, is the great enemy to 
their cultivation in England. When it appears it should 
be carefully cut out with asharp knife, and the plant should 
then be exposed to the influence of a perfectly dry atmo- 
sphere for a few days till the wound has dried, when it 
should be potted in a sandy compost and treated as for 
cuttings. Sometimes the decay begins in the side of the 
stem of the plant, in which case it should be cut away, 
and the wound exposed to a dry air. The cause of this 
decay at the base or in the side of the stems of 
Cactuses is no doubt debility, which is the result of the 
absence of some necessary condition when the plants 
are cultivated in houses or windows in this country. 
Grafted plants, especially Epiphyllums, when worked on 
to Pereskia stocks, are apt to grow weak and flabby through 
the stem wearing out, or through the presence of Mealy 
Bug or other insects in the crevices of the part where the- 
stock and scion join. In this case it is best to prepare 
fresh stocks of Pereskia, and graft on to them the best of 
the pieces of Epiphyllwm from the old, debilitated plant. 
It is no use trying to get such plants to recover, as, when 
once this disease or weakness begins, it cannot easily be 
stopped. 
PROPAGATION. Cactuses may be multiplied from 
cuttings of the stems, from seeds, and also by means of 
grafting; this last method is adopted for those species 
which, under cultivation, are not easily kept in health when. 
growing upon their own roots, or, as in.the case of Epi- 
phyllums, when it offers a means of speedily forming large 
and shapely specimens. From seeds the plants are 
generally freer in growth than when cuttings are used, 
although the seedlings are longer in growing into flowering 
specimens than large cuttings would be. 
