Content of the article:
Azalea is a collective name for varieties originating from two wild azaleas, Indian and Japanese. At present, the genus Azalea is included in the genus Rhododendron, all of whose members possess decorative flowers and need special growing conditions.
Violation of the rules of care, leads to the fact that the plant quickly loses its decorative effect, the leaves turn yellow, blacken or dry out and then fall off. Improper growing conditions lead to the fact that azalea weakens, its resistance decreases, and it becomes a target for diseases.
The factors that cause azalea to shed leaves can be:
- mechanical;
- Chemical;
- biological;
- physiological;
- climatic.
Sometimes, several reasons that act simultaneously, such as climate mismatch and pest or infection, lead to the fall of the foliage.
Physiological factors
When growing rhododendrons, you need to remember that these are seasonal plants, and even with proper care, the absence of disease and good health, home azalea partially loses its foliage. This is a natural process - even evergreens should renew their leaf cover. At the same time, varieties derived from Japanese azaleas( Japanese rhododendron) lose more leaves than varieties whose wild ancestor was Indian azalea.
Natural or physiological loss of foliage, in a healthy plant, occurs after flowering, in a dormant period. Internal metabolic processes in tissues slow down, but azalea leaves fall only partially. In this case, in place of fallen leaves, dormant buds are formed. With the beginning of the growing season, new leaves develop from these buds, which will serve the plant for 2-4 years.
Chemical factors
The toxic substance that can cause a toxic burn to a plant can be accidentally released into the substrate or on the foliage. But usually, chemical burns rhododendrons get from over-irrigation with fertilizer. Symptoms of excess chemicals can result in azalea dropping leaves and sometimes drying out and dying.
Fertilize azalea should be very careful, guided by the rule: "lack of feeding is better than excess."
Another chemical factor is soil acidity. All members of the Heather family need very acidic soil - pH 3.5-4.5.When watering with water, the components of the soil are gradually washed out, and the substrate changes its acidity, becoming slightly acidic or neutral. The plant does not receive the necessary root nutrition, since the microscopic soil fungi that ensure the vital activity of the azalea die. As a result, azalea leaves fall and flowers do not form.
How to avoid : you should water the plant with slightly acidified water, or special microelements.
Climatic factors
Azaleas prefer to grow in cool places, with high humidity( 70-82%).At high temperatures( over 20 degrees) and dry air, azalea drops leaves and flowers. And also ceases to lay new flower buds.
How to avoid: contain azalea at high humidity and a temperature of 12-16 degrees, during flowering, while at rest the temperature is still reduced( but not lower than + 5).
Insufficient watering, or its long absence, can also cause the azalea to shed its leaves. In this case, you need to shorten the shoots and resume watering.
Biological factors
The reasons for which the azalea dries up, or, why her leaves suddenly fall, can be due to:
- fungal infections( the most common pathogens of flowering plants);
- viral diseases;
- diseases caused by bacteria;
- soil pests damaging the root system;
- parasites that harm only the aboveground parts.
The prerequisites for the development of all fungal diseases that lead to the plant wilt are the increased humidity of the substrate, poor drainage and a decrease in temperature. Root rot of rhododendrons, tracheomycosis, late blight( root).Fusarium fungal disease - leads to blackening of the leaves and shoots of azaleas.
Control measures. Preventive measures work most effectively against fungal diseases - monitor the condition of the earthy coma and the plant's well-being. Azalea soil should not dry out, but it should not be very wet. At the first signs of fungal infections, remove diseased branches, and treat the azalea with a solution of a fungicide preparation. If it is a soil fungus, then it is necessary to replace the substrate and process the roots with a disinfecting solution( a weak solution of potassium permanganate will do).
A common home azalea pest, a spider mite, causes the plant's leaves to shrink, turn yellow, fade and fall. With a strong tick lesion, the azalea dries out and it is not possible to save it.
Control measures. At the first signs of the appearance of the parasite( spider web on the leaves, withering leaves and flowers), consider using the magnifying glass the lower surface of the leaf. Ticks are very small, they are not always visible to the naked eye. If a pest is found, the plant should be treated with an acaricidal drug 2-3 times( the interval between treatments 3-5 days).
Preventive measures: sprinkling leaves - the tick multiplies in a dry warm climate.
Defeat thrips - small insects - leads to wilting of the leaves, and with a strong lesion the azalea leaves turn black. In contrast to the fungal infection that causes black, when infected with thrips, the leaves remain dry. Thrips - one of the most dangerous pests, which is very difficult to fight, because of their resistance to some insecticidal drugs.
Control measures. Treat the plant several times with a special insecticide designed to kill thrips. Be sure to replace the substrate, sanitize the flower pot and the roots of the plant.
Shield is another pest that causes wilting and falling off of leaves in azaleas. The insect looks like a small oval protruding speck that is easy to mechanically clean. The color of this pest may vary depending on the species. As a rule, the azalea is affected by a brown and red-brown flaky scale, less often green.
Control measures. At the initial stage of the lesion, it is enough to wipe the leaves with a cotton swab dipped in soapy water. Then, rinse the plant with water.
In case of severe damage, treat rhododendron with insecticide 2-3 times. Be sure to change the substrate, since it will remain eggs scythevy, and soon will re-infection.
You can use drugs that are absorbed into the plant tissue and remain there. Azaleas will not hurt, and the scythe will suck out the poisoned juice from the cells.
In order for home azalea to remain attractive and healthy, besides creating suitable climatic conditions, it is necessary to observe preventive measures and not leave the plant unattended in order to detect pests in time.
Video about growing beautiful azalea home
