Agricultural Engineering And Pruning Hydrangeas

2024 Author: Sebastian Paterson | [email protected]. Last modified: 2023-12-16 13:47

Read the previous part. ← Large-leaved, petiolate and variegated hydrangea

Growing hydrangeas in the North-West of Russia, part 4

Hydrangea requirements for growing conditions

Large-leaved hydrangea

Agrotechnology is, first of all, meeting the requirements of plants for growing conditions. For hydrangeas, these requirements are quite specific, but in general, these plants are unpretentious, easily adapt to different conditions and grow well in our gardens.

All types of hydrangeas have similar requirements for growth conditions, mainly differing in cold resistance and the degree of shade tolerance.

Heat mode

The most cold-resistant are paniculate and variegated hydrangeas. Their shoots ripen well by autumn and are not damaged by frost even down to -40oС. They are not sheltered for the winter; only the root system requires protection in snowless frosts. Treelike hydrangea is not very cold-resistant, but after pruning the frozen shoots, it quickly recovers and blooms the same year.

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Large-leaved, serrate and many other rare hydrangeas in our country are not winter-hardy enough and require, depending on the variety and growing conditions, light or thorough shelter. Many varieties do not overwinter at all outdoors. In large-leaved hydrangeas, young leaves and flower buds often freeze during late spring frosts. Because of this, hydrangeas may not bloom this year.

Moisture

All hydrangeas are moisture-loving, they need systematic, abundant watering, mulching of the soil. These care measures are especially important to observe when planting in sunny places, on sandy soils. Large-leaved hydrangea is afraid of drying more than others. Large panicle hydrangeas can tolerate a fairly long drought. Most hydrangeas, except for large paniculate ones, are not too afraid of high groundwater. In order for the roots not to penetrate too deep into the soil and suffer less from groundwater, hydrangeas must be transplanted and divided in a timely manner.

The soil

Hydrangeas have quite specific soil requirements: they all prefer moisture-consuming, breathable, slightly acidic and even acidic soil. Be sure to add peat, humus to the soil, but not manure. Do not add lime to the planting pit. On neutral and especially alkaline soil, chlorosis of the leaves (yellowing) is possible, associated with poor absorption of iron in such conditions. You should not overfeed hydrangeas with nitrogen, as this delays the growth of shoots, worsens their ripening and, therefore, reduces winter hardiness. Potassium promotes better flowering and increased winter hardiness of hydrangeas, but it is better to introduce it in the form of potassium sulfate. When ash, rich in potassium, is introduced, the acidity of the soil decreases, which is unfavorable for hydrangeas. On acidic soils, phosphorus is absorbed worse, so it is pointless to add it in large quantities.

In colored large-leaved hydrangeas, the acidity of the soil and the presence of various chemical elements in it, primarily aluminum and iron, affect the color of the inflorescences. The more acidic soil and the higher concentration of aluminum and iron salts in it shift the color of the hydrangeas towards the blue side. A decrease in soil acidity and an increase in phosphorus concentration cause hydrangeas to turn pink or red.

All these subtleties are best taken into account when preparing a site for planting hydrangeas. Otherwise, it will be quite difficult to change the situation with the color of the inflorescences with subsequent measures for caring for large-leaved hydrangea. On poor sandy-podzolic soils, rich in iron, old varieties of pink large-leaved hydrangea have a bright blue color. If you want to turn pink hydrangea into blue, you need to increase the acidity of the soil by adding sour peat, sphagnum moss, and coniferous litter to it.

It is possible to increase the concentration of iron in the soil by watering the bushes with a solution of ferrous sulfate (50 grams per bucket of water), and to increase the concentration of aluminum, use aluminum-potassium alum or sulphate aluminum. To water the bushes to change color, you need to several times before coloring the inflorescences. Watering can be repeated in the fall to influence the color next year. The burying of nails and other iron recommended in some articles in order to change the color of hydrangeas is useless. The composition of the soil cannot be influenced by the white color of all types of hydrangeas.

Choosing a place and planting hydrangeas

Serrated hydrangea

The place for hydrangeas must be chosen based on their requirements for growth conditions and achieving maximum decorativeness. The correct choice of place for panicle hydrangea is especially important, since it grows for a long time in one place and does not tolerate transplanting in an adult state. The rest of the hydrangeas can be transplanted several times, choosing the most suitable place.

Hydrangeas do not like windy places, it is advisable to plant them near buildings, but not too close, so as not to increase the danger of freezing of the root system in winter. It is also necessary to protect the fragile panicle hydrangea from snow falling from the roof. When choosing a place for large-leaved and serrated hydrangea, you need to consider the convenience of a winter shelter. Without this, caring for hydrangeas will be significantly complicated.

Planting all hydrangeas is best in spring. Hydrangeas that have wintered in the ground can be planted immediately after the ground thaws, and those obtained from greenhouses with leaves - only after the end of the frost. The planting pit should be spacious enough - from 50x50 cm to 80x80 cm, depending on the size of the plant.

On light sandy soils, it is good to put clay on the bottom, and if water stagnation is possible, drainage is required. With a high standing of groundwater, plants should be planted in an elevated place, which is especially important for paniculate hydrangea. The pit must be filled with a soil mixture with the addition of peat, sand, humus, superphosphate, potassium fertilizer (50 g per pit). Add mineral fertilizers containing nitrogen in small amounts (20 g per pit). There is no need to add fresh manure and lime. It is better to plant a panicle hydrangea with a pronounced stem to the level of the root collar. The rest of the hydrangeas should be planted slightly deep.

Pruning hydrangeas

All types of hydrangeas are beautiful in their own way, but in order to preserve these plants in the garden for many years, for annual and abundant flowering, hydrangeas, like no other plants, need careful and, most importantly, correct pruning. The correct pruning determines how decorative the plant will be, and how abundant the flowering will be. Pruning largely determines the size of the inflorescences. If pruned incorrectly, large-leaved hydrangeas may not bloom at all. In addition, as a result of pruning, the bush is formed in accordance with the design intent.

The main pruning of hydrangeas is done in the spring. In the fall, most species can be left untrimmed. It is only important to cut off the faded inflorescences on panicle hydrangeas, which reduces the breaking off of branches. Heat-loving hydrangeas are pruned in front of the shelter, primarily to facilitate work. Sometimes it is convenient to transfer part of the main pruning to autumn. The timing of spring pruning is not very important. Usually it is carried out after the snow melts before the leaves begin to grow back.

I did not observe the outflow of juice during late pruning noted by some authors. As for other shrubs, after unfavorable wintering and freezing, pruning is best done at a later date, when the degree of damage to shoots and buds is better visible. It is better to rejuvenate old bushes with cutting of large branches at an earlier date. The formation of plants, their pruning are determined by the characteristics of the growth of shoots and the setting of flower buds on them. These features are very different for different types of hydrangea, so we will consider pruning separately for each of the main types.

Tree hydrangea

Treelike hydrangea is a typical shrub with a high shoot-forming ability, a large number of zero shoots. Therefore, it usually forms as a free growing bush. After planting, the shoots are usually shortened for better growth of the bush. Treelike hydrangea has abundant flowering at the ends of the shoots of the current year, and these annual shoots are formed along the entire length of the shoots of the previous year, as well as on older wood and even on underground shoots (zero shoots). The strongest null shoots can be flowering. This allows the hydrangea to be heavily pruned without affecting the flowering.

On tree hydrangea, all types of pruning are carried out annually, carried out on most shrubs. Let's consider them in the sequence in which they are carried out in practice.

Sanitary pruning - for a tree hydrangea, this is mainly pruning the frozen ends of last year's shoots and broken branches.

Rejuvenating pruning - cutting branches older than 3-4 years of age to the base and, first of all, those on which there were weak growths last year.

Thinning pruning - cutting of weak zero shoots, small shoots that are not capable of flowering and thicken the bush.

Pruning for flowering is a shortening of the growths of the last year, leaving 2-4 pairs of well-developed buds on them, from which strong shoots blooming in the current year grow. It is possible to trim all shoots at a certain height to give the bush a more regular compact shape. Often after frosty winters, sanitary pruning of frozen shoots replaces all types of pruning.

Similarly, some species close to it are cut off as a tree: motley hydrangea, ash and others.

Tatyana Popova, gardener

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