Hydrangeas are generous, strong and extremely adaptable plants. They love the shade, but they also grow well in the sun, they live in almost any type of soil and the only two mandatory conditions for their cultivation are regular water supply and good drainage. A rich and fatty soil is preferable to a sandy and low humus one, which will however be fine with the addition of a mixture of leaves, minced rind and manure. The materials that allow hydrangeas to grow and thrive are therefore extremely available: sour peat, chopped zest or even pruning of bushes and thin branches of trees reduced to small pieces. They do not fear the rigors of winter and generally resist well up to six or seven degrees below zero, making cultivation simple even where the winter climate is rather harsh. The talk about pruning is quite simple. As regards the H. macrophylla, which bloom on the wood of the previous year, we will limit ourselves to a cleaning of the dry, to the removal of the old flowers and to the cutting of the weaker stems that will occur by removing the last pair of buds. The common opinion is that the old flower should not be removed until spring, because it is thought to protect the new bud; however lacecaps lose almost all their flowers with winter frost. It is also a good habit, in the plants of five to six years of age, to remove about a third of the hunts at ground level so as to give light even inside and allow a good lignification and vigor (usually the oldest hunts are removed ). As for H. paniculata and H. arborescens, which bloom on the wood of the year, two eyes will be left at the base of each stem (February-March), laying the foundations for a flowering with very large paniceli. Creepers, on the other hand, require limited pruning, which serves more than anything else to contain their growth. For H. aspera, H. serrata, H. involucrata and H. quercifolia only shuffle pruning. Pruning is not essential for hydrangeas: if you let it grow in its natural state (simply in the spring to remove the branches and dried flowers) we will have large and exuberant bushes with irregular shapes, with abundant flowering and smaller flowers. As far as reproduction is concerned, apart from some more problematic species (H. aspera, H. seemani), they can be reproduced by cutting very well, to be carried out from April to October. Not to be discarded is also the system of dividing the roots, easy and safe, and lastly the method of sowing (November-December) which, although giving satisfactory results, does not guarantee the purity of the cultivar. A little more complex is the discussion about the ph issue, which establishes the acidity factor of the soil and consequently determines the color of the inflorescences, the variation of which, however, concerns only H. macrophylla and H. serrata.
Hydrangeas are very different from each other, both as a bearing and for the inflorescences.
These have no petals, but sepals that have changed in color. What we call the "hydrangea flower" is actually a set of tiny flowers, made more evident by the colored sepals. Within the inflorescence we can distinguish between sterile and fertile flowers. The first are those with large, very showy sepals. The others are barely noticeable. Sometimes the inflorescences contain only sterile flowers (in macrophylla mophead, large round inflorescences) other times both (in those with lacecap form, flat inflorescence).
Then there are also those "paniculate" in which the group of flowers takes the form of a panicle: they contain both sterile flowers and fruitful flowers.
However, more and more varied inflorescences are found: with only the margin of the colored petal, with small and curved petals that seem almost curly.