Garden hydrangea ∗ The 10 best care and planting tips

Garden hydrangea: planting and caring for

origin

The garden hydrangea is known as the farmer's hydrangea. Its Latin name is Hydrangea macrophylla. It is considered the best-known representative within the hydrangea genus, because its triumphant advance through the gardens of Europe began in the early 20th century. Numerous breeds and hybrids emerged during this period. Before that, the plant was cultivated in its original range in Japan.

leaves

Garden hydrangeas develop oppositely arranged leaves, which are composed of a petiole and a leaf blade. The stems are short and appear fleshy. You end up in a simply structured blade. It has a sharply toothed leaf margin and is traversed by a raised central nerve from which numerous lateral nerves branch off.

The oval to egg-shaped leaves are slightly wider or narrower depending on the variety. They can be up to six inches long. The base of the leaf blade is bluntly wedge-shaped. The end of the leaf is pointed. The deciduous leaves are colored a dark green. The top of the sheet is shiny.

blossom

The shrubs develop numerous individual flowers that crowd together to form umbrella-shaped inflorescences. They are sitting on thick branches. The outer edge of an inflorescence is covered with sterile flowers that serve as a display. The outer flowers consist of four sepals that are strikingly large and brightly colored.

The color of the sepals varies depending on the pH of the soil. If garden hydrangeas grow in acidic soil, they will develop a blue color. Alkaline soils lead to a red flower color. The intensity of the color varies depending on the variety. Some specimens bloom pure white. When the flowering time draws to a close, a fascinating play of colors emerges. The colors change to green and finally to rusty red. This phenomenon is particularly pronounced with the new Hovaria varieties.

Inside are fertile flowers that are responsible for reproduction. Its chalice is small and bell-shaped. The individual sepals are short and triangular in shape. In Japan, garden hydrangeas bloom between June and August. The flowering time of the plants cultivated in Central Europe extends over the whole summer and continues until October. The flower buds are formed in the previous year.

growth

The wild form of the garden hydrangea grows as a subshrub. The old shoots lignify in the second year, while the fresh shoots are herbaceous. They are deciduous and grow upright with dense branches. After blooming, the inflorescences remain on the plants.

The bark of young branches is greenish in color. It becomes brownish with age. Strong branches appear light brown. They are covered by a felty bark that can be easily removed.

Size

Garden hydrangeas reach heights of growth of up to two meters in their original range. The heights vary depending on the variety and site conditions. The summer bloomers have a large space requirement, which depends on the height of growth. Garden hydrangeas grow at least as wide as they are tall.

use

The summer shrubs have a rustic character. They are suitable for planting in perennial beds that ensure partially shaded conditions. The summer bloomers cut a particularly good figure under taller trees. They beautify small front gardens and bring color accents to dark corners of the garden.

Other types of hydrangea prove to be the ideal planting partner. They can be planted in small groups and rows so that over time they will create a thick hedge. Garden hydrangeas feel at home next to rhododendrons and other plants in shady to partially shaded locations. Between hostas, star umbels, forest goat's beard or astilbe, the floral splendor comes into its own.

Is garden hydrangea poisonous?

Like all hydrangea plants, garden hydrangeas contain various toxins. They are weakly concentrated in all parts of the plant. In addition to hydrocyanic acid, there are also hydrangenol, saponins and hydrangin. Usually, poisoning does not occur after consumption of small amounts. Only large amounts cause symptoms of poisoning. Sensitive people can react allergic to skin contact.

Possible symptoms:

Anxiety
Circulatory problems and dizziness
Shortness of breath
cramps

Garden hydrangeas are slightly toxic to horses, dogs and cats, birds, rabbits, hamsters and guinea pigs. The toxins can lead to circulatory problems or gastrointestinal complaints. Serious symptoms of poisoning only occur after consuming large amounts. Often the bitter taste of the plant scares off animals.

Which location is suitable?

Farm hydrangeas have special requirements for the location. They originally grow on watercourses and damp forest edges. The subshrubs prefer a sheltered place with partially shaded conditions. A north or west facing place where there is no draft is ideal. The plants also grow under strong sunlight. Under these conditions, the demand for water increases sharply. When there is a lack of water, the garden hydrangea sags its leaves and gets sunburn.

What soil does the plant need?

The substrate should be low in lime, rich in humus and moist. A pH value between 4.5 and 6 is ideal. If the pH value is low, the subshrub blooms blue. Higher values produce purple, pink, or red tones. White flowering varieties do not change their flower color.

Propagate garden hydrangeas

The simplest method is propagation from cuttings. Cut off fresh shoots in July. Make sure that the shoots do not have any flower buds. Divide the shoots into small sections, each with two pairs of leaves. The lower pair of leaves is removed and the upper leaves are cut in half. This gives the cuttings more space in the planter to spread out and can put more energy into root development.

Put the cut shoots in potting soil and pour the substrate. To maintain the humidity, you should put a plastic bag or a screw jar over the planter. Ventilate daily to prevent mold from building up. Place the planter in a warm and shady place in the garden or on the terrace. The cuttings take little time to develop the roots.

Prick out

When the cuttings have developed roots, they are pricked out and individually transplanted into small pots. The planter should have a diameter of ten centimeters. Put the pot in a shady place. You no longer have to cover the young plants with foil for further cultivation. In the first winter, the young plants are sensitive to frosty temperatures. Place the planter in a cool and frost-free place in the house. By next spring the plants will have developed to the point where they are ready to be planted in the garden.

sowing

Propagation via seeds is difficult. Many double varieties do not develop seeds. Original varieties and the wild species bear seeds inside the withered inflorescences. They are difficult to collect because they are very hidden and, three millimeters long, are hardly noticeable. You can buy seeds from specialist shops.

To sow the seeds:

Fill the planter with potting soil
Sprinkle seeds
cover lightly with soil
moisten with a spray bottle
Cover the plant pot with foil

Garden hydrangea in a pot

Garden hydrangeas are ideal for cultivation in containers. They embellish balconies, house entrances and terraces. Pot hydrangeas are often offered in stores. This term is misleading as it is not a distinct species. Pot hydrangeas are also varieties of Hydrangea macrophylla.

In the greenhouse

A greenhouse provides optimal conditions for cultivating garden hydrangeas. Pot hydrangeas, which are in full bloom between February and April, were preferred in the greenhouse. These specimens are sensitive to late frosts and need winter protection. Hydrangeas grown in the greenhouse should not be planted in the garden for the first year. At first they are very sensitive to the cold.

Cut garden hydrangea correctly

Farm hydrangeas do not need to be cut. In spring you should remove the withered inflorescences so that the fresh buds can unfold unhindered. Cut back dead and frozen branches. You can recognize this by the gray-brown discoloration. If you are unsure, you can easily scratch the bark. If the tissue underneath is colored yellow-green and appears dry, then the shoot has died.

Proceed carefully with a thinning. Most varieties develop their flower buds in autumn. Pruning measures in spring reduce the number of flowers. There are special cultivars that develop new flowers even after a vigorous pruning.

Fertilize garden hydrangea properly

Garden hydrangeas enjoy a special fertilizer for hydrangeas or rhododendrons. To promote the blue coloration, the fertilizer should contain alum. This aluminum salt contains water-soluble crystals that have an acidic effect.

Free-growing hydrangeas are fertilized for the first time in spring. A second fertilization takes place in early summer. Use a slow release fertilizer that the plant will feed on throughout the growing season. Potted plants are supplied with a liquid fertilizer at regular intervals between March and August. Stop fertilizing as soon as summer draws to a close. Then the fresh shoots have enough time to lignify. The shoot tips remain unwooded, which is typical for half-shrubs.

Water the garden hydrangea

The subshrubs have a high water requirement. In direct sunlight at the place of growth, the plants need larger amounts of water. Water the plants well so that the soil is well moistened. The root ball should never dry out completely. Check the substrate more frequently in hot summer months to avoid drying out. Plants grown in pots should be watered twice a day in summer.

Do not use hard water for watering as this changes the pH value in the substrate. Use soft rainwater. Tap water can be made with a dash of vinegar. Avoid waterlogging as this damages the roots of the hydrangea.

Overwinter

Pot hydrangeas should overwinter indoors in cold winter regions. An unheated greenhouse is the ideal place if it is protected from the direct winter sun. This means that the temperature fluctuations are lower. A dark winter is possible. Pay attention to low temperatures that do not exceed five degrees. Under these conditions the garden hydrangeas stop their metabolism. Light and warm wintering is suboptimal as the bushes are quickly attacked by pests. The lack of rest time inhibits the development of new flower buds.

Specimens growing outdoors require additional winter protection at a young age. A layer of fir branches or brushwood is ideal. Older plants do not need winter protection in mild winter regions. Protect the plant from severe frosts.

Fungal attack

Hydrangea species can be attacked by both powdery mildew and downy mildew. Powdery mildew is a fungus that spreads in dry and warm weather conditions. You can recognize an infestation by the white coating, which is reminiscent of a layer of flour. Downy mildew needs moisture. It leaves a silvery-gray mushroom lawn on the underside of the leaf.

How to fight powdery mildew:

Cut off and destroy affected areas
Means with neem extract or silica help against powdery mildew
Garlic or onion stock combats downy mildew

Brown spots on the leaves indicate leaf spot disease. It occurs when there is a poor supply of nutrients. Just like this fungus, the gray mold also spreads in damp weather conditions. An infestation can be recognized by the gray lawn that stretches over flowers, leaves and shoots. The plant parts wither if the plant is not treated. Optimal care with a good supply of nutrients and water has a preventive effect against these fungal diseases. The plants should be well ventilated.

Diseases

Chlorosis is a relatively common disease that manifests itself in a green color of the leaf veins. The leaves will turn yellow over time. Chlorosis is due to an iron deficiency. An alkaline soil can also lead to this disease. Work rhododendron soil or peat into the soil to lower the pH. A fertilizer containing iron provides a quick remedy.

Certain mycoplasmas or viruses cause a virus in garden hydrangeas. Diseased plants have small and stunted inflorescences. The parts of the plant take on reddish tones. Since this disease can spread quickly to other plants and cannot be controlled, you need to remove the affected plant quickly and, if possible, burn it.

Tips

Support the inflorescences of large-flowered varieties with a curved perennial holder, as their stems can kink slightly, especially after heavy rain and wind. Remove broken shoots. The plant usually regenerates quickly.

sorts

Endless Summer : For shady locations. Very easy to cut. Flowers reliably after pruning in spring. Particularly hardy.
Forever & Ever : For shady locations. Good cut tolerance. Blooms reliably after early pruning. Flowering occurs twice a year. Easy care.
Alpenglow : For locations exposed to wind. Fast growing. Flowers crimson between July and September. Foliage dark green. Height of growth 120 to 150 centimeters.
Hovaria Hobella : Flowers in pastel pink tones, flowers up to 25 centimeters in size. Flowers turn green and red. Grows between 100 and 150 centimeters high.
Hovaria Love you kiss : Flowers white between June and October with a red serrated edge, flowering time lasts four to six weeks, then the flowers turn green and red. Reaches heights of between 100 and 150 centimeters.

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