The main diseases of rhododendron and methods of their treatment. The main diseases of rhododendron Rhododendron has brown spots on the leaves

It would seem that suitable conditions for the development of plants and proper care guarantee success. However, the enemy does not sleep and sometimes he manages to surprise us unexpectedly. Plants that are less resistant and prone to disease are susceptible to the spread of pests. One of these is the rhododendron. The different specific conditions required for shrub growth are a big challenge for the gardener, especially when it comes to pest control. Let's figure out how to defeat rhododendron diseases.

The reasons

If the soil for rhododendrons is devoid of any nutrients, the leaves of the plant are discolored. Potassium deficiency signals brown spots on the edges of the leaves and yellowing of tissues. Brown or reddish spots point to not a large number of boron in the soil. Iron deficiency appears yellowing of the tissues between the veins. When the soil of rhododendrons is overloaded with nutrients, it appears on the leaves chlorosis caused primarily by excess lime in the soil. The leaf blades become yellowish, white or light green, the veins remain dark green. Chlorosis is treated by spraying rhododendron with iron chelate. Use a multi-component fertilizer to strengthen plants. Supporters homemade methods it is recommended to add crushed tree bark to the base, natural fertilizers or untreated peat.

Yellowing leaves

Yellowing of the leaves can be a sign of incorrect soil pH in the garden, when planting rhododendrons, you need to take care of the correct pH. Research can be done independently using Helling pH meter can be bought at a garden store. If the soil is not acidic enough, a rhododendron fertilizer can be applied to acidify the substrate. You can mix the substrate with acidic peat. If the soil reaction is alkaline or neutral, it is imperative to apply acidic fertilizer for rhododendrons.

The rhododendron withers and dies also because of physiological drought, occurs when the plant is not able to replenish stocks from frozen soil. Rhododendron loses water as a result of evaporation, in sunny days. Physiological drought is especially dangerous for plants with big leaves. To prevent or minimize symptoms, it is worth planting a rhododendron in a calm place where the sun only gently warms up during the midday hours. Better in a place among conifers next to the wall of the building. winter rhododendron shade with agrofibre to reduce exposure to direct sunlight. A thick layer of mulch around the plant limits evaporation.

Fungal and bacterial diseases

Rhododendron is especially prone to fungal diseases. The development of the fungus is facilitated by a violation of the rules of care, the presence of various pests on the plant. A sign of the disease is the darkening of the leaves and buds. Fruiting bodies of the fungus appear in the form of black spots on the affected plants. Treatment of the disease begins immediately when the first symptoms appear. Cut diseased parts off and apply a suitable fungicide.

Regular presence light or dark brown spots on the leaves may indicate a fungal disease - leaf spot, the affected rhododendron withers. Leaf spot is caused by fungi and bacteria. Infected leaves dry up and fall off. The fight against spotting is the use of fungicides. Infected leaves should be burned.

A common fungal disease that attacks rhododendron is gray rot, caused by fungi that spread in a humid environment. Mealy appears on leaves, shoots and flowers, gray white coating , as a result, the rhododendron turns brown and dies. Gray rot is destroyed chemicals, spray rhododendron with nettle infusion or horsetail decoction. Infected parts should be quickly removed and burned.

Rhododendron under attack rust and flour beetle. Rust is caused by fungal spores that are rusty in color. The leaves become covered with brown or reddish-red spots and the rhododendron slowly dies. Infected parts are removed, the plant is sprayed with chemicals. Flour beetle contributes to the development of fungal diseases in the garden. Causes a fungus that covers plants with mealy, initially white, then gray-brown bloom. The affected rhododendron withers and dies. The plant must be sprayed with a fungicidal drug, you can use a garlic-based drug.

late blight

Dangerous consequences are brought by diseases of rhododendrons, which have their origin in the soil. Diseases of rhododendrons caused in the soil by fungi are sometimes called withering. These include phytophthora root rot, leaves on infected roots light brown, rapidly darkening spots. The diseased plant withers, completely or partially, the leaves curl, become light green or grayish in color, the infected rhododendron stops growing. Action must be taken immediately, step by step. Sick specimens are removed and burned, not forgetting to disinfect the tools after each action, the plant is sprayed with a fungicide.

Pests

A common pest of rhododendron - furrowed weevil, the presence is easy to notice, characteristic U-shaped passages appear on the leaves. Symptoms of an insect attack are yellowing of the plant and the appearance of visible holes on the leaves. It is difficult to find the weevil, the insect hunts at night, during the day it hides in the soil under the trees. Weevil attacks plants in May-June. The females lay their eggs in the soil, and the eggs hatch into larvae that damage the roots. The larvae overwinter in the upper layers of the soil, between the roots of plants. In the spring, they gnaw the root neck, eating small roots. In May, the larvae pupate and turn into adults.

On the initial stage attacks on a plant, you can catch weevils using a plate with a twig, which are left overnight. Chemical control should be carried out in the evening by spraying the plants with an insecticide. The procedure is repeated every seven to eight days. You need to defeat the pests before they have time to lay their eggs, destroying the larvae is much more difficult. Females can lay thousands of eggs, which will hatch into white larvae with brown heads. You can spray the plants with a solution of tansy. Weevils are also food for moles, millipedes, birds, centipedes and spiders.

Diseases caused by pests

The stubborn destroyer of the rhododendron is rhododendron leafhopper.

Symptoms of the presence of leafhoppers are individual punctures on the leaves, as well as a white molt on the plant. Insect females lay their eggs in September in the buds of the plant; from May to June, yellowish, inactive larvae develop under the underside of the leaves. In July and August, adults feed on the leaves, about a centimeter in length and quite mobile. If the pest is frightened away, it will quickly jump to other leaves. The leafhopper is green, with clear orange elongated pigment spots on the sides. Insects, sucking the juices from the plant, make small damage to the leaves, due to their mobility. smash fungal diseases , leads to the death of flower buds. A plant with symptoms of a disease caused by the presence of rhododendron leafhopper is treated by spraying with an insecticide. Spraying is repeated after ten to fourteen days.

Rhododendron - a delicacy for rhododendron bug, a small winged insect, up to four millimeters in length. The adult specimen has a flat body and transparent wings, the larvae are yellow and small. Large and small individuals feed on leaf sap from inside. A sign of the presence of a pest is yellowish spots on top of the leaves, in the lower part - dark excrement. Affected leaves fall off over time. Fallen leaves must be collected and burned. Bushes are sprayed with insecticide in May-June, when the time of hatching of the larvae is approaching.

It is necessary to conduct an active fight against pests and diseases of rhododendrons at the first symptoms, we use chemical methods of control. Chemical plant protection products are called: in the fight against fungal and bacterial diseases(fungicides), weed control (herbicides) and insect control (insecticides). Spraying the plant chemical agent the indicated doses must be observed, the dosage should not be exceeded. Spraying is carried out in calm weather, best in the evening, so as not to kill beneficial insects. Spraying is not done in the burning sun and during or before rain. Before performing the procedure, it is necessary to check how long the period that must elapse between the application of the chemical protection product and the moment of harvest after the complete decontamination of the product is. For the prevention of diseases of shrubs, plant nutrition helps.

I have only a few evergreen rhododendrons growing in my flower bed. Lately, the leaves have begun to turn yellow. apparent reason. It so happened that their place is the sunniest, there is almost never a shadow.

I recently learned that it turns out that it is precisely such plants growing in the sun that are most susceptible to disease.

To save my rhododendrons, I had to study quite a lot of information about the main mistakes of flower growers, diseases and infections, as well as how to treat them. Willingly share with you, as well as attach photos and videos. After all, no one wants to lose such a flower garden decoration, right?

According to experienced flower growers, major diseases afflict this chic decorative flower due to ignorance of the elementary rules for caring for a plant.

Therefore, before planting it on your site, you should be well acquainted with the basic requirements, how to properly plant and choose a place, what kind of soil is suitable, and how to water and fertilize rhododendron. Here are the main causes of disease.

1. Too much high level soil moisture.
2. Insufficient percentage of soil acidity, which contributes to the weakening of the root system.
3. Planting a plant in areas where there is constant sunlight, contributing to burns of leaf plates.
4. The use of top dressings and fertilizers that are not properly bred or do not suit the rhododendron at all.
5. Drying out of the soil and lack of moisture, especially in winter.
6. An elementary lack of the necessary elements for the active growth of the plant.
7. Temperature fluctuations and freezing of the root system in the cold season.
8. Withering of rhododendron is often due to the fact that the soil contains too much sand and clay.

This plant is quite capricious and sensitive. When planting it in a flower garden or in a flower bed, many factors must be taken into account.

Major diseases

Rhododendron bush needs regular inspection. Periodically, you need to inspect the leaves, stem and branches of the plant, and if you notice any deviations, then hurry to take action.

Tracheomycosis (vascular wilt)

The causative agents of this disease are fungal microorganisms genus Fusarium. They strike vascular system plants, causing the stem and leaf blade to dry out. There is also a gray coating. Gradually, the bush dies, and its root system undergoes a rapid process of decay.

As preventive measure a rhododendron bush can be treated (spray and water a little root zone) with 0.2% Fundazol.

If the bush is not treated in time with Bordeaux liquid, then it will not be possible to save the rhododendron. All affected parts of the plant are carefully removed and burned.

Bacterial root cancer

The root system is affected by a soil-like bacillus of the genus Agrobacterium, which is capable of destroying the root cells of this plant. The main symptoms are:

1. Rounded and large outgrowths are formed on the root and root neck, which acquire over time dark color and solid form.
2. Flowering is weakened and the bush begins to grow more slowly.
3. The next manifestation of the disease is the decay of the root collar and rhizome. The plant dies.

The infection can spread to planting material and maybe for a long time persist. Rhododendron should be treated with Bordeaux liquid or its analogues. Very affected plants should be destroyed along with the rhizome.

Mosaic of rhododendron

The causative agent of this disease is Rhododendron mosaik virus. Descriptions in different sources may vary slightly, but the main manifestations remain the following:

• Yellowish spots and small swollen areas appear on the leaf plates of the plant.
• Along with yellowish spots on the leaves, dark brown and green also appear, resulting in a mosaic pattern. The thickness of the sheet becomes smaller.
• The flowering of rhododendron sharply declines and growth becomes completely slow.
• The disease most often affects the bushes of alpine varieties.
• The carriers of the disease are harmful insects: bugs, aphids and others.

To get rid of the disease, it is necessary to remove the affected leaves and branches at the initial stage. It is also recommended to treat with Confidor and Aktellik. If the defeat is too strong, then the flower must be destroyed.

Rust

The bush is susceptible to this infection more often in the autumn months. Blisters of yellow, reddish and red and dark brown tint appear on the surface of the leaf plate. During the spring period for reverse side leaf, you can see reddish spores with a reddish tinge.

This disease manifests itself only on the leafy part of the plant, so it is worth removing rust-affected leaves at the first stage of infection.

Then it is possible for prevention and in medicinal purposes spray the bush with Bordeaux liquid or preparations, the main constituent element of which is copper.

Chlorosis

The edges of the leaves of rhododendron are stained with yellowish spots. A disease appears due to too high a percentage of acidity in the soil or due to a deficiency of nutrients necessary for the development and growth of the plant.

To defeat the disease, rhododendron is sprayed with a solution of magnesium or iron sulfate at the rate of 7 grams per liter.

Types of rot that affect the plant

There are several of them, and they appear on different parts rhododendron. Let's consider everything in turn:

Late blight rot

The causative agent is a fungus of the genus Phytophthora. The reasons for the defeat of the plant by this type of fungus can be several reasons:

• Lack of a drainage layer when planting or too small a layer that does not pass moisture well.
• Excessive accumulation of moisture and soaking.
• The plant was originally a carrier of this disease when purchased.

The main signs: the stems and leaves are covered with dark spots of a burgundy hue, sometimes they turn purple. Then the root system begins to rot, the plant slows down in growth, and general state bush deteriorates sharply.

Rhododendron should be treated with Fungicide, Quadris, Fundazol or Bordeaux liquid and significantly reduce the amount of watering.

Gray rot

The causative agent is Botrytis gray and Botrytis ash gray. Infection occurs with the help of spores that can be transmitted by air. They have many forms.

The defeat occurs in the spring, and ash-gray botrytis extends only to dead parts of the plant. And from there, the disease passes to the healthy parts of the flower.

Contributes to the disease and excessive soil moisture, and dampness of the air. Mushrooms secrete toxins, which are transferred from the damaged areas to the entire healthy bush, infecting it. External signs are:

1. All parts of the plant are infected.
2. It is characterized by the appearance of spots of dark brown or brown shades. After a while they dry out upper layer starts to crack.
3. In raw rainy weather the affected areas are covered with a grayish, strongly pubescent coating.

It is necessary to remove all necrotic areas from the bush, and treatment with 0.2% foundationazole is also possible.

root rot

The main parts that suffer are the stems and the root part. At the first stage, for no apparent reason, the sheets begin to dry out. Then the buds on the stems become dark brown. The last stage is the darkening and rotting of the flower root.

It is recommended in this situation to destroy diseased plants or parts thereof. To prevent infection with root rot, it is necessary to control the watering of the rhododendron and soil moisture. You also need to maintain the level of soil acidity, depending on the plant variety.

Also, there are such types of rot as:

• Dry white rot.
• The death of shoots.
• Bud rot.
• Rot of seedlings and young seedlings.

Varieties of spotting

This section also has several types. The most common are the following:

Pestalocyanic

The disease affects the stem part and leaf plates of the flower. Spots of a dark brown shade of irregular shape appear on them. They are framed by a thin brown edging.

There are more spots on the shoots than on the leaves. Spore pads are usually found on the mottled, infected part of the leaf.

Sick areas are carefully cut off and the bush is treated with Bordeaux liquid or Camulus.

Anthracnose spotting

Brownish patches appear on the upper parts of the leaves. The leaves then dry up. Dark spots then grow to the stem part. The affected leaves and shoots are cut off, and the bush is sprayed with Bordeaux liquid.

In addition, the following types of rhododendron spotting are distinguished:

• Septoria.
• Phyllostic.

wax disease

It is characterized by the appearance of several types of fungal infections that have different effects on parts of the plant.

Brownish-red outgrowths may appear and the stems thicken, sometimes parts of the flower are overgrown with white pillows - outgrowths. There are fungi that cause yellowing of the foliage or a white coating with spores on the inside.

Here is an incomplete list of diseases that affect rhododendron. Only proper care, prevention and timely measures will help keep the plant healthy and blooming.

The first sign of leaf disease in azalea is the occurrence of dark spots on the back side leaf plate, and sometimes the entire stem of the plant.

Typical color spots:

• brown;
• grey;
• dark grey;
• black.

Why do the tips of the leaves or the entire leaf plate turn black in rhododendron? This is possible for several reasons:

The blackening of azalea leaves does not depend on the season. The following factors influence this process:

• improper care of the plant (excessive watering);
• the appearance of fungal infections;
• viral diseases;
• ticks.

IMPORTANT. Wrong care for azalea: use of poor-quality drainage, excessive substrate moisture, low or very heat- all this provokes the development of fungal infections, which ultimately lead to blackening and falling of the leaf plates houseplant.

If the leaves are damaged by black thrips, they must be treated with a special chemical preparation, for example, a ready-made karbofos emulsion. Blackening in this case can be either partial, at the tips or along the edges of the sheet plate, or complete, on the entire surface of the sheet.

It is impossible to cure an azalea from Fusarios at a late stage, so you will have to get rid of the missing plant. If the disease is detected at an early stage, then it is necessary to use the drug fundazol. In the fight against rhododendron mites, the most effective is chemical drug diazinon.

After applying various drugs, it is necessary to get rid of the affected parts of the plant. It is necessary to remove all remaining damaged leaves without touching the branches, even if they have become completely bare. Then check the condition of the root system and transplant the azalea into a new soil. The air temperature in the room during the recovery period should be about 20 - 22̊ C and lighting without direct sunlight.

Learn more about how to revive a dying indoor azalea, can be found in .

In order for the azalea to keep its beautiful for a long time appearance and make others happy lush bloom, it is very important to monitor the intensity of its watering and water temperature. The ideal water temperature for irrigation is the same as indoors or a maximum of 1 to 2 degrees higher. Such water is easily absorbed by the root system and saturates it with useful elements.

Water for irrigation should be soft. Before watering, it must be boiled, cooled and drained. upper part. The lower layer of water, where there is a harmful sediment, is strictly prohibited for irrigation. From time to time, it is advisable to water the azalea with slightly acidified water with lemon juice. The proportion of liquid for irrigation: 3 drops lemon juice per 1 liter of warm water.

After the illness, the air around the plant should be even more humid. To increase immunity, azalea must be sprayed special solution prepared from Elina preparation. Watering should be carried out with acidified water at least 3-6 times a week.

For the prevention of diseases in azalea, it is important to consider the following factors:

• light intensity;
• air ionization and watering;
• room temperature;
• soil feature;
• soil fertilizer;
• special care during the flowering period.

Azalea should be kept in a light or semi-dark room where there is no access to direct sunlight. She feels best on balconies, loggias, where the temperature does not fall below + 5̊ C, on the northern and western windows.

For irrigation, it is necessary to use melted or boiled water, avoiding stagnation of liquid in the pot pan. Maximum comfortable conditions content - above 12 - 15̊С. To plant an azalea, heather soil or a mixture of peat, needles and river sand should be used.

Azaleas need to be fertilized in summer and winter. In the warm season, you can use ammonium sulfate, and in the cold - superphosphate. Pinch and prune the plant - after flowering, in the spring. At the end of summer, the azalea must be thinned out and cut off weak shoots, carefully treating the cut points with a special tool.

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We consider the care of rhododendron in open field spring, summer, autumn and winter. Described in detail: watering, fertilizing, fertilizing, pruning and flowering, as well as preparation for winter, pests and diseases.

Plus regional features: the Moscow region, the Urals, Siberia, the North-West (Leningrad region) and the Middle lane.

How to care for rhododendron in the garden in spring and summer?

Planting lays the foundation for further care of the plant in the open field. If it is planted in suitable place into the right soil mix, then further care much easier. We described how to do this correctly in a special material - see the bottom of the page.

In spring, the flower wakes up after winter and you need to help it recover, save it from drying out and rotting. Caring for rhododendrons in spring and summer consists in regular watering and spraying, top dressing, pruning and disease prevention.

Save the kidneys from drying out

1. After active snow melting (mid-March - early April), the ground can slowly thaw, and the sun can bake. The evaporation of moisture by the buds and leaves increases, and the roots are shackled and have not awakened.
2. Therefore, free the bush from last year's frozen mulch (you can loosen and remove half of the layer) so that the ground near the roots thaws faster.
   This will allow the roots to start working and save the buds from drying out. It is especially important to quickly remove the mulch if the winter was cold or with little snow.
3. Water the Rosewood hot water(even boiling water) and spray warm water.
4. If the rhododendron wintered without shelter, then make a protective shield from the sun on the south and west sides. Drive in stakes and stretch the fabric. Read more in the article "Preparing for winter" - link at the bottom of the page.
5. After the soil has completely thawed to a depth of 20-30 cm (beginning - mid-April), on a cloudy day or in the evening, remove the protective cover (covering material) or winter shelter.

If signs of burns are still found on the shoots, the buds have dried up and do not begin to grow, then spray them with warm water every day, and every 3-4 days with a growth stimulator (Zircon, Epin, etc.).

Flower buds of rhododendron in the spring after removing the winter shelter

pruning rhododendron

Trim the plant only if necessary (once every 2-5 years): if you need to update an old specimen, shorten a bush that is too tall, or remove frozen stems.

Classical shaping pruning is not necessary due to the fact that the natural shape of the plant is correct and attractive in 99% of cases.

Rules

• Pruning is carried out before the buds swell (mid-March - early April).
• The cut must be made directly above the dormant growth point - a small pinkish swelling-thickness. Be sure to learn to identify them.
• Treat each cut with garden pitch.
• Provide pruned specimens with regular watering and fertilizing during the active growing season.

Species features

1. Small deciduous species need to be rejuvenated after 5-7 years, and large ones (Canadian and others) every 14-18 years.
2. Small-leaved evergreen species up to 4-5 years old should be pruned to stimulate branching. If desired, you can even create a ball shape. Since powerful flowering is observed even in 20-25-year-old branches, they are rarely pruned.
3. Evergreen species from large leaves prune every spring 1-3 shoots from their total number in order to develop better side branches. Otherwise, after a few years, these shoots will become ugly and long branches with leaves only at the top. The leaves themselves will become small, and the flowering will be weak.

How to prune a large bush?

Trim the shoots in places 2-4 cm thick near the dormant buds. After 20-25 days, the dormant buds will wake up and grow, and the next year the decorative effect of the bush will be restored.

How to rejuvenate a bush?

To rejuvenate bushes that are very old or seriously affected by frost, winds, cut branches at a level of 30-40 cm from the soil near sleeping buds: first one half, and a year later the other, to facilitate rehabilitation.

Rejuvenating pruning of an evergreen rhododendron after an unsuccessful wintering

Advice

If you want a thick and sprawling deciduous rhododendron, then pinch the first 3-4 years after planting seasonal shoots in June, and in September cut off all weak stems inside the crown.

How to water a rhododendron?

For a plant, a deficit or excess of water is undesirable. A prolonged lack of water prevents the seasonal growth of shoots, impairs flowering and reduces decorativeness (leaves dry out, turn yellow, and old leaves fall off en masse).

• Leaves signal a lack of moisture. Due to the loss of turgor, they droop, wither and become matte. The lack of watering exacerbates the situation: the leaves turn yellow, turn brown (edges and central vein), dry out and die.

"Rosewood" is harmful to stagnant water, and it is sensitive to excessive moisture in the soil. This disrupts the development of the flower, as little oxygen is supplied to the roots. At the same time, the leaves also turn yellow, wither and fall off.

The frequency of watering is affected by the planting site, the composition of the soil mixture and climatic conditions. Rhododendron, planted in a favorable place and in the right soil mixture, needs more rare watering.

Ideally, the frequency of watering is determined independently by the condition of the leaves and the amount of precipitation. As soon as they have become matte (the shine has disappeared) and have drooped a little, they need moisture. Therefore, follow these signs and accumulate your personal experience.

The most important periods for watering: active growth and development (April - mid-July) and preparation for winter (mid-September - November).

April - July

During the period of intensive vegetation, during the flowering period and after it, an increased need for moisture is observed, the root ball should not be allowed to dry out. Therefore, every 4-7 days, water 10-14 liters of water per trunk circle under an adult bush.

If spring and summer are hot, and there is little rain, then you need to water more often and supplement with spraying. Spray the leaves with water every 2-3 days in the early morning or late evening.

August and September

At the same time, in August and September, it is already necessary to water less often - 10-14 liters of water every 8-12 days, otherwise secondary growth of the stems is possible.

Soil loosening

Others believe that it is desirable to weed 3-4 times over the summer, but very carefully: loosen 1-2 times in one place 3-4 cm deep.

Tips

Water for watering and spraying "rosewood" should be soft and acidified (pH 4.0-5.0) - a teaspoon of citric or oxalic acid per 10 liters of water.

Top dressing and fertilizers

Proper nutrition provides good growth and development, powerful and beautiful bloom, and also increases the resistance of rhododendron to adverse external factors (pests, frost, disease, wind).

• The most important periods: March - April and immediately after flowering.

It is advisable to use liquid top dressing. At the same time, a low concentration of nutrient solution is needed, since the rhododendron grows slowly, and the roots lie close to the surface.

Signs of need for feeding

Light, pale, glossless leaves. Yellowish green shoots. Little seasonal increase. Weak or no flowering. Old leaves fall off en masse in August.

Leaf discoloration is the first symptom of a nutrient deficiency.

What fertilizer to use for rhododendrons?

A good option would be to use a special fertilizer, it has a balanced composition of mineral elements and fast solubility. You can also use complex mineral fertilizers, such as "Kemira-universal" and organic.

organic fertilizers

According to experts, organic top dressing are more preferable because they are better absorbed than mineral ones and improve the soil (friability, moisture and air permeability).

• Of these, it is better to use: blood meal, semi-rotted cow dung and horn flour. Do not use: bird droppings, pig and horse manure.

Fill semi-rotted manure with water 1:15-20 and leave for 3-4 days. Water the bush before top dressing (the root ball should be completely wet). You can only use from April to the end of June.

In spring or autumn, semi-rotted manure can be scattered near the bush with a 4-5 cm layer on the surface of the earth, so that with incoming moisture from rain or melting snow necessary elements fed him.

Mineral fertilizers

Since rosewood prefers acidic soils, an acidic fertilizer must be used. These are mainly: potassium nitrate, superphosphate, potassium phosphate and sulfate - ammonium, potassium, calcium and magnesium. Under the ban - fertilizers containing chlorine.

The nutrient solution for top dressing should be 0.1-0.2% i.e. 1 gram of a substance per liter of water, and potash fertilizers – 0,05-0,1%.

Top dressing schedule

After winter, the rhododendron needs to be fed, and if the acidity level has increased (“”), then you need to slightly acidify the soil.

To acidify, add a tablespoon of vinegar, oxalic or citric acid. Especially if the bush grows on loamy or sandy soil.

1. After the snow melts (late March - early April), water the plant with mullein infusion or dissolve 20 g of ammonium sulfate, 6 potassium sulfate and 8 g of superphosphate in 10 liters of water.
   After that, immediately mulch the trunk circle with a layer of 6-8 cm with a layer of coniferous sawdust or peat.
   Such a mulch will reduce acidity, retain moisture longer and prevent the active growth of weeds. The base of the bush cannot be covered, it is better to sprinkle it with coarse sand to prevent rot and stagnant water.
2. After 20-25 days or 10-14 days before flowering (beginning of budding). The same composition.
3. During flowering or immediately after it. In order for the bush to bloom more powerfully or restore strength: 8 g of superphosphate and 6 g of potassium sulfate per 10 liters of water.

To maintain the desired acidity of the soil after the first and second top dressing, it is advisable to water with this solution: 8 g of potassium phosphate and potassium nitrate per 10 liters of water. If watered with mullein infusion, then there is no need.

2nd option

1. Before flowering. Apply 20-30 grams of special fertilizer or "Kemira wagon" (2-3 grams per liter) under the bush. In any of the options, add nitrogen for growth: 5-10 grams of carbamide (urea) or ammonium nitrate.
2. Immediately after flowering. Similar feed.
3. Late July - early August. 30 g of superphosphate, 15 g of potassium sulfate + 10 g of complex mineral fertilizer per 10 liters of water. Top dressing accelerates the lignification of shoots and prevents their growth in late summer - early autumn.

3rd option

1. After the snow melts (end of March - beginning of April). Scatter on the surface of the earth for 1 m2 or a copy above 100 cm: 40 g of ammonium sulfate and 20 g of potassium sulfate and superphosphate or 50 g of ammonium sulfate and magnesium.
2. After flowering (late May - early June). 20 g of ammonium sulfate and 10 g of potassium sulfate and superphosphate.

This option is much lighter than liquid dressings and is suitable for those who have a large number of plants planted.

Tips

• Fertilizers that reduce the acidity of the soil, such as wood ash, should not be used.
• Do not use long-acting granular fertilizers, as they can cause secondary growth of stems in August, which will freeze in winter. They are designed for the European climate with six warm months a year.
• If, nevertheless, secondary growth has begun, then spray the bush with potassium sulfate - 10 g per liter of water.
• The editors of the magazine "Feast of Flowers" recommends using more organic fertilizers than minerals.

Disease prevention

In late April - early May, shed or spray the "rose tree" with copper-containing fungicides (copper oxychloride "HOM", copper sulphate).

Preventive treatments are especially important for species: Canadian, Ledebour and evergreen species.

Flowering rhododendron

All gardeners are waiting for the unique and powerful flowering of the bush every year. Despite their attractive appearance all season long, it is the luxurious inflorescences that create the maximum decorative effect and captivate millions of eyes.

When does rhododendron bloom or flowering time?

Flowering time depends on climatic conditions specific locality and year, variety and condition of the plant. Usually the flowering period lasts from April to June. Early-flowering species (Dahurian, Canadian, Ledebour) bloom in mid - late April in early - mid-May cease to bloom.

Then evergreens large-leaved species they begin to bloom in early - mid-May, and soon deciduous species and varieties based on them join them.

How long or how long does a rhododendron bloom?

The flowering period for different species and varieties is different amount days, on average 16-20 (30-45). The duration of flowering depends on many factors: the amount of light, temperature, species characteristics, the amount of nutrients, etc.

Care after flowering

In order for the "rose tree" to bloom profusely every year, break out the inflorescences immediately after they have faded (there will be no seeds!). The inflorescence at the base breaks off effortlessly with your hands, but you need to be careful not to damage the young shoots.

This procedure will help the bush to direct all its forces to the laying of lateral buds and abundant flowering next season. It will also become more magnificent, because not one, but 2-3 young shoots will appear at the base of the inflorescence.

Then water the plant abundantly and feed with potassium-phosphorus fertilizer.

• It is especially important to break out inflorescences in large-leaved species.

Rhododendron Katevbinsky "Grandiflorum" (Grandiflorum)

Rhododendron: care in the fall and preparation for winter

Caring for rhododendron in the fall comes down to preparing for wintering, which includes proper watering, disease prevention, mulching and, if necessary, protection with covering material or the construction of a shelter.

Watering

In September we water more often than in August, and in October we need abundant watering before winter, especially in dry autumn and for evergreen species and varieties. Water them until November frosts. If in November it is not possible to go to the country, then it is better to plant only deciduous rhododendrons.

In a rainy autumn, often in the suburbs, Leningrad region, watering rare.

• A sufficient amount of moisture in September - October - November contributes to the successful wintering of the plant, increases its endurance, and drought reduces resistance to external negative factors.

Disease prevention

In late September - early October (before frost), treat the plant with a "Bordeaux mixture", blue vitriol or a copper-containing fungicide to prevent fungal diseases.

Preparing for winter and shelter for the winter

By the beginning of October, flower (large, rounded) and growth (smaller and sharper) buds of the next year should form near the bush. The main task is to preserve these buds until spring from freezing, burns, breaking and drying.

• Since this is a very serious moment in the care of rhododendrons, we covered it in a special article - see the link at the bottom of the page.

Pests and diseases

Depending on the species and variety, the susceptibility of rhododendrons to diseases and pests differs. According to the observations of flower growers, in an open and sunny area, evergreen species are more likely to suffer from pests and diseases than in light partial shade.

At the same time, strong and strong plant less prone to meeting with "uninvited guests". Therefore, proper care in the open field for rhododendron is of decisive importance here.

Pests

Potential Growing Problems

Why do rhododendrons have brown leaves?

Often the leaves become Brown color(central vein and edges) not affected by any fungal disease but due to lack of moisture. This is the main factor.

The tips of the leaves turn brown and dry out due to a sunburn in the spring or a lack of moisture in the background of the heat.

Why do leaves turn yellow?

In addition to a lack or excess of moisture, often the reason lies in the low acidity of the soil. Settle and acidify the water before watering, feed with a buffer solution - the composition in the first feeding option.

Flower buds crumble

The reason is high air temperature and low humidity.

Why do leaves curl?

Flowers wither due to insufficient watering or low humidity. Spray the plant more often.

If it happened after the first autumn frosts You don't need to worry, it's a natural process. Read about it in the article “Preparing for winter”.

ADDITIONS TO THE ARTICLE:

We wish you the right development and beautiful flowering!

Plants suffer from severe waterlogging, unbalanced top dressing, low soil acidity, winter physiological desiccation and sunburn. Can be damaged by fungal diseases ( spots, rust) and chlorosis(acute lack of iron and manganese, which occurs when the soil is low in acidity and disappears when correct mode top dressing). By collecting and burning damaged foliage, sanitary pruning, and treating plants with suitable fungicides, many diseases can be resisted.

Damage rhododendrons most often garden snails and slugs (collection and destruction helps), rhododendron bugs, spider mite, mealybug, weevils, scale insects, rhododendra fly, against which insecticides help well.

Major diseases and symptoms

Vascular (tracheomycosis) wilt caused by fungi of the genus Fusarium ( Fusarium oxysporum). The disease begins with root rot, damages the vascular system. Plants turn brown and dry, starting from the top of the shoots. On dried leaves and stems, a grayish coating forms - mycelium.

Late blight rot caused by fungi of the genus Phytophthora ( Phytophthora). Large purple-brown spots appear on the root neck and on the base of the stems, the roots turn brown and rot, the plant fades.

Gray rot caused by fungi of the genus Botrytis ( Botrytis cinerea). One of the most common diseases of many crops, since the spores of the fungus are carried both with air and with water spray. On all parts of the plant - leaves, buds, stems - vague brown brown spots. Damaged tissues quickly dry out, they form a grayish coating - mycelium.

Septoria spotting caused by fungi of the genus Septoria ( Septoria). Small round reddish spots appear on the leaves, the center of which gradually turns white and black dotted fruiting bodies of the wintering stage of the fungus form on them. Diseased stems shrivel, dry out, the leaves turn yellow prematurely and fall off.

Prevention and control measures

• It is necessary to carefully examine the planting material upon purchase, select suitable conditions for plants and follow the basic rules of cultivation.
• Severely affected branches and leaves are pruned, in autumn plant residues are collected and burned.
• In spring and autumn, as well as after flowering, bushes are sprayed Bordeaux liquid or its substitutes (drug Hom).

Major pests

spider mite (Tetranychus urticae) infects plants in hot and dry summers. Adults are so small that they are very difficult to see (about 0.5 mm). Most often, an attack can be seen when the underside of the leaves is covered with a thin cobweb, and the leaves become lifeless, brownish and fall off.

Acacia false shield (Parthenolecanium corni). The larvae, resembling small shiny brown outgrowths on the bark, stick tightly to the branches and "pull" juices from the plant. As a result, it weakens, gradually dries up.

furrowed weevil (Otiorrhynchus sulcatus). This black small (up to 1 cm) beetle is harmful at all stages of development. The larvae damage the roots, and adults feed on leaves, do not shun buds and bark.

Control measures

• Compliance with the rules of agricultural technology.
• In early spring, plants are sprayed with the biological preparation Fitoverm, or chemical: Aktara, Actellik, Arrivo, Iskra, Inta-vir. In case of severe damage, the treatment is repeated after 7-10 days.
• During flowering, plants are not sprayed so as not to harm bees and other pollinating insects.
• In order to avoid addiction of pests, preparations must be changed.