Pinguicula Grandiflora (_Great Irish Butterwort_).--This handsome,
hardy bog-plant produces deep violet-blue flowers in August and
September. It may be grown in any damp soil and increased by division.
Height, 1-1/2 ft.
Pinks.--Will live in almost any soil, but if large blooms are required
rich earth is essential. They are increased by pipings taken in May
or June. These should be planted out in October, but must be given a
well-drained position, as too much wet is injurious to them. Do not
set the roots too deep, but let the collar of the plant be on a level
with the soil.
Pinus.--As a tall specimen tree nothing is more graceful than the
Corsican Pine (_Pinus Laricio_). P. Strobus Nana is a curious dwarf
variety, rarely exceeding 3 ft. in height. The Argentea Aurea is also
of dwarf habit. Its leaves, which are green in summer, change to a
bright golden colour in winter. The Umbrella Pine (_Sciadopitys_) is a
very striking conifer, and does well everywhere. It gets its name from
its leaves being set at regular intervals round the branches, like
the ribs of an umbrella. The Pinus may be increased by layers, or by
sowing the cones in spring, after they have opened out, in rather
sandy soil, covering them lightly.
Piping.--This consists in drawing out the young grass, or shoots, from
the joints of Pinks, etc., from May to July being the time for doing
so. Place them in light, sandy soil, and cover them with a hand-glass.
Towards the end of September they may be planted out in beds or potted
off in rich, light loam. In either case they must not be planted too
deeply. The crust of the soil should be level with the collar of the
plant. If the pots are put into a frame the plants will require very
little water during winter, but as much air should be given as is
possible. In March re-pot them, using 8-1/2-in. pots.
Platycodon (_Japanese Balloon Flower_).--Hardy and elegant herbaceous
plants, requiring a sandy soil. They may be raised either from seeds
or from cuttings of the young growth; they flower in July. Height, 1
ft.
Platystemon Californicus.--Pretty hardy annuals which thrive in a
sandy soil. They are easily raised from seed sown in March or April,
and bring forth their flowers in August. Height, 1 ft.
Pleroma Elegans.--A beautiful evergreen shrub for a greenhouse. Pot in
equal parts of loam, peat, and sand. It flowers in July. Cuttings may
be struck in peat in a rather warm temperature. Height, 4 ft.
Plumbago.--These pretty evergreens will grow in any soil, and can be
propagated in September by cuttings of half-ripened wood having
a heal, planted in a sandy soil, and kept near the glass in a
greenhouse. They flower in June. Height, 3 ft. P. Occidentalis is
a charming greenhouse climber. P. Capensis Alba is a greenhouse
evergreen shrub, flowering in November, and growing to a height of 2
ft. P. Larpentae is good for a sunny border, in light soil: it bears
terminal clusters of rich violet-purple flowers in September. Height,
1 ft. Plumbagoes require very little attention in winter.
Plums.--Almost any soil will grow this useful fruit. Young trees may
be planted at any time, when the ground is friable, from November to
March, but the earlier it is done the better. The situation should be
somewhat sheltered. In exposed positions protection may be afforded
by a row of damson trees. Many varieties are suitable for growing on
walls or sheds, where they are trained into fans, as cordons, and
other decorative designs; but it must not be overlooked that until the
trees are well established a great deal of fruit is necessarily lost
by the severe pruning and disbudding which is required to bring the
tree into shape. A pyramid-shaped tree is useful, and is easily
grown by training one straight, central shoot, which must be stopped
occasionally so that fresh side branches may be thrown out, which of
course must be kept at the desired length. A bush tree about 7 ft. in
height is undoubtedly the best form of growth, and needs but a minimum
amount of attention. In pruning wall trees the main object is to get
the side-shoots equally balanced, and to prevent the growth advancing
in the centre. The bush form merely require the removal of any dead
wood and of cross-growing branches. This should be done late in the
summer or in the autumn. The trees are frequently attacked by a small
moth, known as the Plum Fortrix, which eats its way into the fruit
and causes it to fall. In this case the fallen unripe fruit should be
gathered up and burned, and the trees washed in winter with caustic
potash and soda. For growing on walls the following kinds may be
recommended: Diamond, White Magnum Bonum, Pond's Seedling, and Belle
de Louvain for cooking; and Kirke, Coe's Golden Drop, and Jefferson
for dessert. For pyramids and bushes, Victoria, Early Prolific, Prince
Engelbert, Sultan, and Belgian Purple are good sorts. In orchards
Plums should stand 20 ft. apart.
Poa Trivalis.--A very pretty, dwarf-growing, variegated grass. Plant
in a moist situation in a rich, light, loamy soil. It is increased
either by seed or division.