Hydrangeas in the garden
The botanical name is hydrangea, some tens of species belong to the genus, almost all originating from Asia, and in particular from China, Japan and Korea; most of the hydrangeas grown in Europe are cultivars or hybrids of hydrangea macrophylla, the first species imported into Europe by Portuguese missionaries, already in the 1700s; in all these centuries of cultivation the varieties of hydrangea macrophylla which we can find on the market have become hundreds.
These are vigorous shrubs, with deciduous leaves, which produce large leathery leaves in the spring, with a rough, deep green color, forming a dense, compact, semi-spherical shrub, which can reach 200-300 cm in height if not pruned; from late spring to autumn the hydrangeas produce numerous inflorescences, consisting of small fertile flowers, and large sterile flowers, consisting of 4 large sepals. Varieties of hydrangea that produce spherical inflorescences, consisting only of sterile flowers, are widespread; less widespread, although not less beautiful, are varieties with inflorescences of lacecaps, umbrellas with small fertile flowers in the center, and around them, almost forming a crown, large sterile flowers.
Hydrangea macrophylla produces flowers of various colors, from pure white to cream, from pale pink to red, from lilac to intense blue. In many varieties the color of the flowers denotes the pH of the soil, the lower the pH the more blue the flower becomes, the higher the pH the more the flower tends to red. Flowers that are just pink or cream-colored are often the result of a soil with a neutral ph. Hydrangeas are plants from undergrowth, with a cool and humid climate; they can easily remain in full sun, but in the hot Italian summers it is difficult to keep the soil cool and humid under the August sun, unless you intervene every 2-3 hours with watering, and water at a temperature not too different from that of the 'environment.
In general, if you do not live in the mountains, you tend to grow hydrangeas in partial shade, where they enjoy a good brightness, but sheltered from the sun during the hottest hours of the day; often simply placing them against a low wall, which gives the plant a cooling effect from the heat, can be sufficient.
During the winter the hydrangeas are without foliage, and they bear frost without problems, even if intense and continuous; in spring they begin to produce their big buds, if the climate is not naturally wet we will have to start with watering, in order to keep the soil always damp and fresh; the waterings will become very abundant and regular with the arrival of the beautiful season: in summer it may be necessary to water our hydrangea every morning and every evening. Often the plants tend to wither, if the soil is too dry: the water supply makes them resume within half an hour.
From March to October we supply fertilizer for flowering plants; if we want our hydrangeas to show off a beautiful bright blue color we will have to provide fertilizer for acidophilic plants, and grow our hydrangea in soil for acidophilic plants. If instead we are content to enjoy the flowers of the color that nature wants to give us, we can use a good garden soil, well drained and rich, and fertilize with fertilizer for common flowering plants.
Often, over the years, the hydrangea shrubs tend to rise excessively, stripping off the lower part, to prevent this from happening in general every year, at the end of winter, removing about a quarter of the apex of each branch, in order to favor a more compact vegetation.
In addition to the "common" hydrangea macrophylla on the market we also find other hydrangeas, which in principle are cultivated in the same way.
Very common is also H. paniculata, with white flowers, in inflorescences in the shape of stubby panicles; or also H. arborescens, a species native to the United States.
H. quercifolia has large leaves similar to oak leaves, while H. petiolaris has a creeping or climbing habit.