About flower hydrangea
Blue hydrangea macrophylla (Thunb.) Ser. sin. H. hortens:s Smith.)
A member of the Saxi fragaceae family, originally from China, Japan. Stem erect, leaves oval with serrated margins. Flowers are white, pink, red, clustered in a large round umbel. Inflorescences are formed at the apex of annual shoots. Hydrangea likes abundant watering and fertilisation, a cool room and a semi-shaded position. Propagation is by cuttings taken in January, February and March, 5 cm long from the suckers in the pot. Hydrangeas propagated earlier have more flowers and are stronger. Propagation is carried out under glass or polythene sheeting in sandy peat soil or washed sand. Rooting takes 2-3 weeks.
Once rooted, the cuttings are planted in pots 8-10 cm in diameter, with a soil mix of well-rotted peat, heather, leaf soil and sand (1:1:1:0,5). After 4-6 weeks, the young hydrangeas shall be potted again in pots 12-13 cm in diameter. The soil is made up of equal parts of well-rotted peat (preferably peat moss), peat moss and an appropriate amount of sand.
Blue hydrangea in summer
In summer, hydrangeas should be kept indoors or outdoors in partial shade, with the pots buried in the ground. On hot, sunny days, spray not only the hydrangeas but also the walls and the ground of the container with water 1-2 times a day. In addition, they are watered every 10th day with diluted cattle manure slurry (4-5 parts water to 1 part slurry).
Some people practise planting hydrangeas without pots in the spring, in June, in an outdoor bed made from peat soil. In autumn, the hydrangeas are potted up again and kept in a container until frost. To avoid autumn rain, they are covered by windows. Hydrangeas grown in this way are said to be stronger, shorter in stature and flower more profusely.
Information source: https://en.wikipedia.org/wiki/Hydrangea