The Garden Magazine, September, 1920 
13 
Prunus: Double forms are the most popular though the single 
forms are very desirable. They may be had in flower from 
January until they bloom outside. The plants may be potted 
from the open border into pots or tubs and grown on the same as 
fruit trees for forcing. They may be used a number of years, 
provided they are not abused with too much heat. After 
flowering they should be pruned hard and fed liberally to induce 
strong growth. Place them in full sun to ripen the wood 
thoroughly. Some of the best are P. Pissardii, with purple 
leaves and white flowers, P. Rhexii with double white flowers 
(this is free and forces well in an intermediate house), 
P. japonica, another double white, 4 feet high, which may be 
forced into bloom soon after Christmas, P. nana, dwarf with 
almond-like flowers, P. persica with double flowers ranging from 
white to deep red, and P. triloba, double rose-colored flowers. 
Pyrus: Both floribunda and spectabilis when grown on 
dwarfing stock are useful for forcing. 
Ribes: The most serviceable are R. aureum, with fragrant 
yellow flowers, and R. sanguineum, (var. atro-sanguineum), 
with red. Both are easily forced. 
Robinia hispida: Drooping racemes of rose colored flowers, 
which can be readily forced into bloom if established in pots 
and not subjected to too much heat, make this highly desirable. 
Rhododendrons: For forcing purposes we have had to look to 
Europe for our early flowering Hybrid Rhododendrons, and as 
they are affected by the recent ruling of the Federal Horticultural 
Board, in its Quarantine 37, there is some doubt whether or not 
these plants will be avail- 
able in the immediate 
future. Among the best 
varieties for early use are 
R.Pink Pearl, considered 
the best and easiest to 
handle, R. Nobleanum, 
bright red, though it 
comes white when forced 
hard, R. flavum (Azalea 
pontica) yellow and 
sweetly scented, and R. 
praccox, rosy purple. 
For use during February 
and onwards R. caucasi- 
cum album, R. Everes- 
tianum, Grand Arab, 
John Waterer, Lord John 
Russell, Boule de Neige, 
Cynthia, and John Wal- 
ter are best. 
Spiraea: Some species 
force readily in an inter- 
mediate temperature, to 
flower in February. By 
attention to pruning and 
feeding they may be used 
three successive years. 
The best are S. arguta, 
which has small star- 
shaped flowers in great 
profusion, S. prunifolium 
flore-pleno with long 
wand-like shoots, S. 
Thunbergii, another 
small-flowered variety 
and S. Van Houttei with 
white flowers in Haw- 
thorn-like bunches. 
Staphylea colchica: 
Useful forforcingand pro- 
ducing large panicles of 
pure white flowers which 
may be had at Christmas. 
Syringa (Lilac): Large quantities of Lilac blooms are to 
be seen in our florists’ stores during the winter which are 
obtained from plants specially prepared and grown for 
forcing. The best varieties for this purpose are grown 
on stocks of the common Lilac, the scion being inserted six 
inches above the ground. They are then allowed to grow on 
for two seasons, strong shoots only being allowed to remain. 
At the end of the second year they have eight to twelve strong 
growths each. At the beginning of August each plant is root- 
pruned where it stands, so that it will go into a seven-or eight- 
inch pot. This root pruning aids greatly in ripening the wood, 
for the holes made by the spade in the operation of root-pruning 
not being filled in allow both sun and air to get at the roots. In 
September the plants are potted and plunged until needed for 
use. When required for Christmas it is usual to put them in a 
dark place in a house with a temperature of from 75 to 80 
degrees L. and keep them well syringed. The heat and darkness 
blanch the colored varieties. When wanted for spring flowering 
less heat is required, though a high temperature is essential 
to get flowers quickly. After flowering the plants are cut back to 
two or three eyes and stood in a cool house to “break.” When 
all danger of frost is over they are planted out and rested for a 
year, although those that have been hard forced should be left 
for two years. While in the nursery all weak wood and suckers 
should be pruned away, only the strong shoots being allowed to 
remain. By growing them on, large plants may be obtained 
carrying from twenty-five to thirty heads of flowers. The most 
commonly used varieties 
are Charles X, Marie Le- 
graye, President Grevy, 
Madame Lemoine, Al- 
phonse Lavalle, and Ru- 
bra De Marley. Syringa 
persica requires an inter- 
mediate temperature and 
may be used two years 
in succession. 
Viburnum: TheSnow- 
ball tree is easily forced, 
though if given too much 
heat the flower stems 
come weak and are easily 
broken. V. tomentosum 
plicatum has dense heads 
of pure white flowers and 
is one of the best for 
forcing purposes. They 
should be rested alter- 
nate years. 
It is always to be 
borne in mind that spe- 
cial feeding of all plants 
is necessary when growth 
is active — and of course 
the process of forcing is 
really a stimulation into 
not only early but ab- 
normally active growth. 
All useless shoots should 
be removed as soon as 
they are observed — and 
they must be watched 
for carefully — for not a 
particle of energy should 
waste itself in the de- 
velopment of parts that 
are not necessary. The 
whole enterprise fails if 
the material is unfit 
through weakness or any 
constitutional fault. 
THE BOUGAINVILLEA HAS COME INTO ITS OWN 
Possessing the general exuberance of its tropical nativity in combina- 
tion with ethereal delicacy in the flower itself, this is now established 
as the Easter substitute for the outlawed (by quarantine) Azalea 
