HYDRANGEA ARBORESCENS.--North America, 1736. This is a plant of large
growth, but the flowers are greenish-white, and by no means conspicuous.
H. HORTENSIS (_syn Hortensia opuloides_).--China, 1790. This is an
old-fashioned garden shrub that is only hardy in the south and west of
these islands and in the vicinity of the sea. In some of the forms
nearly all the flowers are sterile, the calyx-lobes being greatly
expanded, and in others the outer flowers only are sterile. According to
the nature of the soil the flowers vary much in colour, some being pure
white, others pink, and others of varying shades of blue. There are some
very beautiful and distinct varieties, such as H. hortensis japonica; H.
hortensis Otaksa, with large panicles of sterile blue flowers; H.
hortensis rosea-alba, with large rosy flowers; H. hortensis Thomas Hogg,
a very free-flowering and welcome form; H. hortensis mandschurica, and
H. hortensis stellata flore-pleno, with partially double flowers, are
worthy of attention.
H. PANICULATA.--Japan, 1874. This is one of the most distinct species,
in which the flower-heads are elongated, not flat, as in most other
species, and from which the finest form in cultivation has been
obtained. This is H. paniculata grandiflora, in which the flowers are
sterile and pure white, forming large panicles often a foot in length.
It is a magnificent variety, and, being perfectly hardy, should be
extensively planted for ornament. The flowers are produced in late
summer, but remain in good form for fully two months, dying off a rich
H. QUERCIFOLIA.--Oak-leaved Hydrangea. Florida, 1803. This species has
neatly lobed leaves, and terminal panicles of pinky-white, but partially
H. SCANDENS.--Climbing Hydrangea. Japan, 1879. This is not very hardy,
but with the protection of a sunny wall it grows freely.
The Hydrangeas require a rich, loamy soil, and, unless in maritime
districts, a warm and sheltered situation. They are readily propagated
by means of cuttings.