All types and varieties of hydrangea are moisture-loving. Adult specimens are more light-requiring and cold-resistant than young ones. Hydrangeas are demanding on the richness and moisture of the soil; calcareous soils are unsuitable for them. In culture, they do not tolerate strong or prolonged shading. All this must be taken into account when choosing a landing site.
Read about species suitable for cultivation in our zone on the page Hydrangea.
Planting and leaving
Soil preparation and planting. The most favorable time for planting hydrangeas is spring, during the period after the soil thaws and before the buds begin to bloom. Planting holes are dug 40-50 cm deep, 40 cm in diameter. Their size depends on the height of the shrub and soil fertility. If the soil is not rich, then the planting hole should be deeper. Each pit is filled with fertile soil (humus and peat) with the addition of 50 g of mineral fertilizer.
The planting material is dug in a timely manner with a clod of earth. Before planting, the broken branches and roots of the seedlings are slightly pruned with pruning shears. When planting a shrub in the center of the planting hole, a mound is poured flush with the upper edge, then the root system of the seedling is carefully laid out, directing the roots in different directions. When planting, a slight deepening of the root collar is allowed, no more than 2-3 cm, otherwise the plant will develop poorly. The earth around the bush is tamped tightly so that voids do not form in the root zone, leading to their drying out. After planting, the bush is watered, for the effectiveness of irrigation, a stream of water is directed into the hole under the plant so that the entire soil is saturated with moisture, and the soil is moistened to a depth of 40-50 cm.
Mulching the trunk circle helps to protect the roots of hydrangea plants from overheating, reduces the growth of weeds. Organic mulch in the form of wood chips, bark or peat is scattered in an even layer (7-10 cm thick) around the shrub. As it decomposes, this substrate will become part of the soil and acidify it to some extent, which is very important for hydrangeas. The best time for mulch application is late spring, when the soil is still sufficiently moistened, but already well warmed up. In autumn they mulch after the onset of a period of stable negative temperatures. The contour of the covering made of mulching material must correspond to the projection of the crown of a hydrangea or a whole landscape group, or must exceed it by 15-20 cm.
Top dressing. For normal development, lush flowering and the establishment of flower buds of the next year, hydrangeas need organic and mineral fertilizers. There are special fertilizers for hydrangeas that are rich in magnesium and iron. Fertilizers are applied to the soil not only before planting, but also during the period of their intensive growth. The first feeding is carried out in late May or early June with a liquid fermented solution of poultry manure (diluted with water in a ratio of 1:10) and a complex mineral fertilizer (20 g of superphosphate, 10 g of urea, 10 g of potassium nitrate). Re-feeding is carried out every two weeks. So that the hydrangea shoots have time to lignify by winter, feeding is stopped at the end of July or early August.
Annual pruning tree hydrangea and ash hydrangea allows you to regulate the number and size of inflorescences. After pruning, these shrubs develop fewer inflorescences, but they are usually much larger than those without pruning. Since the inflorescences develop on the shoots of the current year, the shoots are cut off in early spring, in March-April. In adult and strong plants, 3/4 of the shoot height is cut with a sharp pruner, leaving 2-3 pairs of buds. Frozen and weak shoots are cut out at the same time. In the fall, all faded inflorescences are cut off.
Pruning the strong and fast growing shoots of the petiolate hydrangea causes strong branching of this vine and provides a thicker cover on the support or soil.At Sargent's hydrangea, all unbranched shoots are cut annually to a height of 25-30 cm.
Panicle hydrangea can be formed in the form of a tree on a low trunk. To do this, from a two-year-old seedling grown from an apical cutting, only one most powerful shoot is chosen, and all the rest are completely cut out. The main shoot is shortened to the strongest bud, until a stem with a height of about 1 m is grown.In subsequent years, to form a crown, the top of the shoot on the stem is pinched, and all shoots appearing on the stem are promptly removed. As the bush develops, all weak shoots are cut out, leaving only 4-5 strong shoots for branching. This procedure is repeated annually.
To protect young and insufficiently winter-hardy varieties of hydrangea from frost, it is required winter shelter... The easiest shelter is to mulch the near-trunk circle of shrubs with fallen leaves, straw, sawdust, a small layer of peat or branches of spruce branches. It is suitable for tree hydrangea varieties that are relatively winter-hardy and can tolerate low winter temperatures. Mulching is carried out in dry weather immediately after the first frost.
More thermophilic species, such as large-leaved hydrangea, petiolate, are gently bent to the ground in late autumn, trying not to break, pinned with hooks, covered with coniferous spruce branches, or fallen leaves. They should not be laid on the ground, but on boards or on a layer of spruce branches. To protect the bushes of Sargent hydrangea with stiff shoots from the cold, the crown is tied with kraft paper, or with a covering material - lutrasil, spunbond. In early spring, as soon as the danger of severe frosts has passed, the mulch and shelter should be removed, but not earlier than mid-April. This work is carried out on a cloudy day, in the late afternoon, so as not to cause burns by the rays of the bright spring sun.
Hydrangeas are rarely damaged pests. A spider mite sometimes settles on the leaves, and green leaf aphids start up mainly when growing or forcing hydrangeas in closed ground. In wet years, a fungal disease, powdery mildew, can develop on the leaves and young shoots of hydrangea. Hydrangeas are sensitive to the content of lime in the soil and when there is an excess of it, the leaves become lighter as a result of chlorosis. This disease can also manifest itself with an increased content of humus in the soil.
Reproduction of hydrangeas
Hydrangea is propagated by cuttings, dividing bushes, grafting or seeds. The best time for successful rooting of hydrangea cuttings is during the flowering period (mid-July). Small one-year lateral shoots are suitable for cutting cuttings, which are formed in sufficient quantities on each plant. They should not break when bent. Strong and thick shoots with hard wood, taken from well-lit parts of the crown, root less well. Hydrangea can be cut before flowering (in June), in this case, when cutting the cuttings, a piece of last year's shoot is retained at its base - the cut "with the heel" is cut off.
For rooting cuttings, a light, moisture-absorbing substrate is prepared from high-moor peat and well-washed coarse-grained sand (in a ratio of 2: 1). Sand is poured on top with a layer of 2 cm. The slightly acidic reaction of peat promotes root growth. To increase the moisture capacity, chopped sphagnum moss can be added to the substrate. For rooting, cuttings are dusted with Kornevin. When planting, the cuttings are deepened into the substrate by 2-3 cm, placing them at a distance of 3-5 cm from each other with a slight slope. Rooting of hydrangeas occurs in 3-4 weeks at a temperature of 16-20 ° C and slight shading. (Read more about grafting technology - in the article Green cuttings of woody plants)
Hydrangea can also be propagated by dividing the bush. In spring or autumn, the bush is dug up, divided into 2-3 parts, so that at least 2-3 renewal buds remain on each plant.
Seed propagation of hydrangeas is more troublesome and not suitable for varietal plants. Due to the fact that its seeds are very small, it is safer to sow in boxes. The soil substrate should be light with a slightly acidic reaction of the medium. It is prepared from leafy earth, humus, peat and coarse sand (in a ratio of 2: 2: 1: 1). Seeds are sown superficially without stratification, only lightly sprinkled with sand. For seed germination, crops are regularly watered using a sprinkler. Seeds sown in spring (from March to May) sprout in a month. In order for the seedlings to develop normally, liquid fertilizing with complex fertilizer is needed. By autumn, they grow up to 30-40 cm in height. Seedlings overwinter in open ground under a reliable shelter.
Discoloration of inflorescences
Hydrangea inflorescences of large-leaved, paniculate and ground cover cream and pinkish color, if desired, can be changed to blue, pale purple or blue. The fact is that the color of hydrangea flowers depends on the acidity of the soil. Pink and crimson flowers are with a slightly alkaline reaction, and they turn blue on acidic soil, while it must be borne in mind that white inflorescences practically do not change their color.
In an alkaline environment, hydrangeas are not able to use iron from the soil, on which the color of flowers depends (this nutrient is absorbed in an acidic environment). To get blue inflorescences on alkaline soils, plants are watered with a solution of iron salts. To enhance the blue color, iron shavings or small iron objects are buried under the bushes. The brighter the initial color of the inflorescences was, the more intense the blue or purple color will be. In some cases, both blue and pink inflorescences can appear on the bush at the same time. The inflorescences can turn blue if the plants were planted in peat soil, but the blue color can become dirty.