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Hydrangea oakleaf was first described by the American naturalist William Bartram in the late 18th century. But it took its place in the gardens of the New and Old Worlds much later, since the first experience of growing an ornamental culture was unsuccessful. Only at the beginning of the 20th century, when the agrotechnics of oakleaf hydrangea was understood, it was able to enter the design of decorative plantings, almost completely displacing its relative, the macrophile. It is a beautiful and elegant plant with good weather resistance.
Description of oakleaf hydrangea
Oak-leaved hydrangea (Hydrangea Guercifolia) is a deciduous shrub with a height of 150 to 200 cm. The stem of the culture is straight and hardened near the roots. The growth of oakleaf hydrangea is up to 50 cm per year. The root system is pivotal, with several large leads located at a depth of 40 cm.
A feature of this species are its leaves of a characteristic "oak" shape. They can be up to 25 cm in size and have sharp and jagged edges. The pattern of oakleaf hydrangea veins is embossed and clear.
Large seven-lobed leaves of oak-leaved hydrangea have pubescence and are able to change color
During the season, there are two changes in the color of the vegetative part of the plant. In early spring, the foliage of the hydrangea is oak-leaved, dark green. Since August, the process of its repainting begins in a deep red color, which in September changes to dark burgundy. In fact, only green leaves are completely pubescent; as it changes, the hairs remain only on the lower side.
Flowers of oakleaf hydrangea are collected in large panicle inflorescences.
Most often they are conical in shape and consist of many white flowers up to 30 mm in diameter. Their smell is sweetish, barely perceptible. Blossoming of oakleaf hydrangea is long: it begins in mid-June and lasts until the end of September.
Oakleaf hydrangea varieties with photos and names
There are about a dozen popular plant varieties. All of them find application in landscape design.
Harmony
This variety of oakleaf hydrangea has an interesting difference in the anatomy of the flowering part. In other respects, it repeats the original culture.
The inflorescences of the Harmony variety have a larger number of flowers and a length increased to 30-32 cm
The mass of hydrangea flowers is so significant that the stems can sag.
Snow white domes
Similar to Harmony, it has more flowers per inflorescence. Moreover, its shape may not be elongated, but spherical. The rest of the culture is identical to the original oak-leaved hydrangea.
The main difference between the Snow-white domes is the round shape of the inflorescences.
Burgundy
One of the most beautiful varieties. He has few differences, but they all seem to "enhance" the characteristic features of oak-leaved hydrangea. For example, Burgundy has the brightest color in autumn. Young leaves, on the contrary, are rich green. Shoots are golden yellow.
Burgundy leaves most of all resemble oak in shape - there are rounded lobes, there are no hairs
Flowering lasts from late June to August. The petals first have a white or cream shade, then change it to pinkish.
Tennessee clone
It has relatively small, numerous inflorescences. Their length rarely exceeds 10-12 cm.
The flowers of the Tennessee clone are creamy, they have a characteristic petal shape, narrowed at the base.
The number of inflorescences on a bush can exceed 30-40 pieces. Which, on average, is twice as much as any other variety.
Snow Queen
This variety of oakleaf hydrangea was bred to produce large flowering parts. It has large massive flowers (up to 5 cm in diameter) and inflorescences. Leaves are relatively thin, with little or no pubescence.
The mass of inflorescences in Snow Queen is very large, so the branches with them are pressed to the ground
The color of the petals of this variety can be white or pinkish. Sometimes on the same plant, multi-colored shades are found.
Hydrangea oakleaf in landscape design
The culture is capable of performing all the roles of a large and beautiful bush with abundant flowering. It can be used as the center of a composition or to give accents to a particular subject. In mixborders, oaky hydrangea is usually used, shortening the shoots to 1.2-1.5 m.
The shrub can also be used to create continuous plantings of monoculture.
Often you can find oakleaf hydrangea as a hedge or a high curb
However, there are some nuances. They relate to the fact that, despite the good winter hardiness of oak-leaved hydrangea, some of the buds can freeze from frost. Moreover, this is observed even at relatively low temperatures. And, since the generative buds of the oak-leaved hydrangea are renewed every two years, it may happen that some of the bushes are left without flowers, which will significantly worsen the appearance of the garden.
Winter hardiness of oak-leaved hydrangea
Despite its almost subtropical origin, the plant has good frost resistance. Most varieties of oak-leaved hydrangea have a frost resistance zone of 4, that is, they are able to withstand temperatures up to - 35 ° C.
Some varieties have much lower resistance (6th zone, that is - 23 ° C). In any case, when purchasing seed, you need to make sure that the culture is suitable for a particular climate.
Planting and caring for oaky hydrangea
Planting is best done in spring, early or mid-April. If there is a desire to do this in the fall, then October will be the optimal month.
Selection and preparation of the landing site
The culture feels best in partial shade. The quality and fertility of the soil does not play a special role for the oak-leaved hydrangea. There are only two main requirements for the site, but both are critical:
- the level of acidity pH in the range of 5.0-6.5;
- no wetlands.
The site practically does not need preliminary preparation, holes are dug a day before planting planting material, watered abundantly and nothing else is done with them.
Landing rules
It is best to plant oaky hydrangea in the morning. A substrate is placed in the dug holes, consisting of equal proportions of the following components:
- garden land;
- peat;
- sand;
- humus.
Next, a seedling is placed on the resulting mixture and the soil is poured to the edges of the hole. After planting, a little watering is performed, the soil is loosened and mulched with sawdust or peat.
Watering and feeding
The culture has enough moisture from natural precipitation. Therefore, oakleaf hydrangea is watered exclusively during drought.In this case, the frequency of watering is from 1 to 2 times a week, depending on the moisture content of the upper soil layer. One bush requires up to 10 liters of water.
Top dressing is done every month, starting in May. In total, they should be applied 4-5 times. The first consists of nitrogenous fertilizers (carbamide in the amount of 50 g per 1 sq. M.), The rest - from potassium-phosphorus. In the latter case, it is best to use 30 g of superphosphate per 1 sq. m.
Pruning hydrangea oakleaf
Starting from the age of two, to make the plant decorative, it is pruned. In the spring, it is of a sanitary nature - damaged and diseased branches, as well as those that grow inside the crown, are removed.
Before budding begins, the crown is given the shape of a semicircle
In the fall, only the faded parts of the plant should be cut off. This procedure is done just before hiding the bush for the winter.
Shelter for the winter oaky hydrangea
Despite the rather high frost resistance of the plant, its buds can freeze out even at relatively low temperatures (about - 20 ° C). So that the plant does not lose its decorative effect next year, it must be covered.
One-year and two-year-old bushes should be earthed, covered with sawdust on top and covered with polyethylene
Adult specimens of oakleaf hydrangea are bent to the surface of the soil and covered with sawdust, spruce branches or fallen leaves. Put a plastic wrap on top.
Sometimes the following technique is used: the branches are tied, and a metal frame is installed above the bush, which is filled from the inside with fallen leaves. As in other cases, polyethylene is pulled on top of it. When the snow just melts, the shelter is removed.
In more detail, the shelter of an oak-leaved hydrangea for the winter in the video:
Reproduction
The plant is propagated in all available ways:
- seeds;
- cuttings;
- dividing the bush;
- layering.
Unlike many ornamental crops, oak-leaved hydrangea seed propagation is quite effective and fast, the material is sown in seedling boxes in February. They use peat, sand and garden soil as a substrate.
The first shoots hatch in March. Seedlings are grown all summer long and then planted in open ground.
The division of the bush is applicable for mature plants with more than a dozen large stems. It is allowed to divide the root with a shovel without digging it out of the ground.
Reproduction by cuttings is most effective. They are harvested in July from last year's stems, which have at least three pairs of leaves.
The lower leaves are cut off, and the cuttings themselves are placed in water in which a few drops of Epin are dissolved
The roots appear in about a month, after which the cuttings are planted in individual containers, where they grow indoors until April next year, when they are planted in open ground.
Diseases and pests
Oak-leaved hydrangea is resistant to most diseases, but fungal infections sometimes attack it. The most dangerous for the culture is gray rot. It affects plants of any age.
Symptoms of rot - the appearance of gray spots on the leaves
Usually, the cause of the disease is a violation of the conditions of the plant - high humidity or stagnation of water at the roots. Treatment consists in spraying the culture with copper-containing preparations and changing the irrigation conditions.
Of the pests, the oakleaf hydrangea is most often attacked by spider mites. But here the reason is completely different - excessive dryness.
Small spider mites most often hide on the lower part of the leaves
In the fight against this pest, you need to use acaricides: Actellik, Aktaru or Fitoverm. But, as in the case of diseases, the main thing in treatment is to adjust the conditions of the plant.
Conclusion
Oak-leaved hydrangea is a beautiful crop with large inflorescences and decorative leaves. It can be used for a variety of designs in temperate gardens and parks.The culture has good immunity to pests and diseases. To preserve decorativeness, it is recommended to cover the plant for the winter.
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