Contents
Many gardeners are faced with the fact that blueberry leaves turn red. And then the question arises whether such a phenomenon is considered the norm, or whether it is a sign of the onset of a disease. In fact, the causes of reddening of the leaves can be very diverse, this article will help to deal with them in more detail and learn about the methods of saving the plant.
Why do blueberry leaves turn red?
In order to correctly diagnose the causes of reddening of blueberry leaves and select the most effective treatment, on which, in some cases, the life of the plant may depend, it is necessary. First of all, start from when and under what conditions this phenomenon began. As a rule, blueberry leaves usually turn red in autumn and early spring, with sharp drops in temperature.
Why do blueberry leaves turn red in autumn
You should not worry only if the blueberry leaves turn red in the autumn, as this is a natural phenomenon. In autumn, the plant begins preparing for winter, accompanied by a redistribution of nutrients. During this period, the color of blueberry leaves acquires a rich burgundy-red hue. Depending on the natural conditions of the region, the leaves usually begin to turn red in October or November.
Why blueberry leaves turn red in spring or summer
If blueberry leaves turn red in summer or spring, you should take a closer look at the causes of this phenomenon. There may be several factors. Blueberry foliage turns red in spring, usually during cold snaps. The cause of reddening of the leaves in summer is most often fungal diseases such as phomopsis and stem cancer.
Why do blueberry leaves turn red after planting
The most common reason for blueberry leaves to turn red after planting is placing the plant in soil with the wrong acidity. Blueberries do not like too acidic soil, and on neutral soils, its foliage begins to turn red.
Why blueberry leaves turn red and what to do
There are not many reasons why blueberry leaves turn red in summer or spring. These include:
- Low air temperature;
- Low acidity of the soil;
- Lack of nutrients in the soil, and in particular deficiency of magnesium and phosphorus;
- Infection with fungal diseases that can be asymptomatic for a long time, which is extremely dangerous, since this can lead to infection of neighboring plants;
- Root rot affecting blueberry bushes growing in damp areas. To prevent its development, it is recommended to transplant the plant to areas mulched with compost, pine bark or sand.
Low temperature
In early spring, when consistently warm weather has not yet set in, blueberry leaves often turn red due to sudden temperature fluctuations and cold snaps at night. Such a reaction is normal, you should not rush to perform any manipulations with the plant, with the exception of preventive treatments for fungal diseases. You should watch the shrub for a couple of weeks, with warming, the color of the leaves should change to the usual green.
Low acidity of the soil
If soon after planting healthy blueberry seedlings, the green leaf blades of the plant began to turn red, the cause may be insufficient soil acidity. A characteristic sign of insufficient soil acidity is that the leaves, as a rule, turn red in their entirety, and are not covered with individual spots.
The best option for blueberries, regardless of variety, is light soil with an acidity level of 3,5 – 4,5 pH. If the acidity of the soil is lower, the color of the leaves changes. To increase the acidity index, it is recommended to shed the soil with a special solution, which can be prepared by mixing citric or oxalic acid (1 tsp) with water (3 l). You can also acidify the soil with 9% acetic acid dissolved in water.
After such an event, several days should pass before the blueberry leaves acquire their previous color. However, if after 10-12 days the foliage has not turned green, the soil should be re-irrigated with acidic solutions.
Phomopsis
Phomopsis is a fungal disease that can easily be confused with stem cancer. Phomopsis causes drying and twisting of the tops of young shoots. The main cause of the disease is waterlogging of the soil. The Phomopsis viticola fungus most often infects bushes growing in areas with a high level of groundwater or in regions with high air humidity.
Through the tissues of the tops of young shoots, the fungus rapidly spreads to their bases, as a result of which the greens turn red and fade. The disease begins to appear in June. Its first signs are small dark red, almost black, round or oval dots that form on the leaves. If the disease is not treated, perennial old branches will soon become infected.
If signs of the disease are found, all affected shoots and leaves from the blueberry bush must be cut and then burned. The bush itself must be treated with fungicides. For this purpose, you can use drugs such as Topsin, Fundazol, Euparen. Spraying is carried out three times: twice before flowering (with an interval of a week) and once after picking berries.
stem cancer
Another reason that blueberry leaves turn red can be an extremely dangerous fungal disease – stem cancer. When stem cancer infects blueberry bushes, the leaf scar zone is first covered with small red spots, which subsequently grow and turn brown. Over time, the spots grow together, then they begin to gradually spread over the surface of the shoots, causing their death. On lignified shoots, as a result, the spots form expanding sores, at the site of the appearance of which the bark exfoliates strongly.
With the development of stem cancer, blueberry leaves turn red long before the onset of autumn. The cause of the disease is most often improper care of the plant: waterlogging of the soil, excess of the rate of application of nitrogenous fertilizers.
Getting rid of stem cancer is almost impossible. To protect blueberry bushes from this dangerous disease, it is recommended, first of all, to avoid planting plants in areas with high soil moisture and a high level of groundwater.
For prevention, blueberries are regularly sprayed with 3% Bordeaux liquid. The procedure should be carried out twice a year: in early spring – before the leaves bloom, or in late autumn – after they have already fallen.
Also during the growing season, blueberry bushes must be sprayed with fungicides. Well proven means such as Fundazol, Euparen, Topsin. Fungicides are applied three times before flowering and three times after harvest. The interval between spraying should be about a week.
Preventive measures
The choice of blueberry seedlings should be approached responsibly, their appearance should be healthy, it is better to give preference to varieties resistant to fungal diseases.
Basic preventive measures:
- Compliance with planting rules: pre-fertilization, control of the degree of soil moisture, planting seedlings in sunny areas at a distance of at least 2 m from each other.
- Regular inspection of the bush, during which thickened, as well as dry and diseased shoots are removed. By pruning the bush, air circulation improves, which prevents the development of many fungal diseases.
- Preventive treatment with Bordeaux liquid twice a season.
- Preventive treatments with fungicides before flowering and after harvest.
- Timely collection and burning of fallen leaves.
Conclusion
Do not panic if blueberry leaves turn red, a change in pigmentation does not always indicate the development of a disease. One of the most common causes of this problem is improper plant care: too acidic soil, early planting, watering with cold water. Another common cause is fungal diseases, with timely treatment of which it is often still possible to save blueberry bushes.
