The spots on the leaves of the hydrangeacan be of different colors and shapes. Their appearance usually signals serious problems resulting from fungal disease or cultivation errors. Untreated bushes very quickly lose their attractive appearance and bloom less. Seewhere the stains on hydrangea leaves come fromand how to treat plants with such stains.
Stains on leaves of climbing hydrangea
Yellow spots on hydrangea leaves
Yellow and brown, dry, irregular spots on hydrangea leaves are caused by burns Burns of hydrangea leaves may occur as a result of exposure of bushes to strong sun with low substrate humidity or too intensive fertilization. To avoid this type of damage, hydrangeas should be planted in places that offer them shade during the hottest hours of the day. In addition, a sufficiently thick layer of mulch should be spread around the bushes, which helps to retain moisture in the soil. When using hydrangea fertilizers, follow the manufacturers' recommendations and use granulated slow-release fertilizers if possible.
Brown spots on hydrangea leaves
Brown spots on hydrangea leavesmay indicate a fungal disease. The most common cause of these symptoms ishydrangea leaf spotThis disease affects hydrangeas that grow in gardens and grown in pots. Cercospora hydrangea, which causes leaf blotch, strongly infects hydrangea leaves, causing small (3-6 mm in diameter), round, brown or purple spots to appear on them.These spots are located on both sides of the leaf blade.
Hydrangea leaf spot
Symptoms first appear on the lower leaves of the plantand then spread to the top of the bush. Whole shrubs lose vigor, grow less, and it is more difficult for them to form flower buds. Although the infection of the shrubs occurs in spring,symptoms of hydrangea leaf blotchare not visible until late summer. The development of the disease is favored by high air humidity, while in periods of drought its development and spread are inhibited.
Good to know!
Symptoms of leaf spot may vary between species of hydrangea. For example, in hydrangea (Hydrangea macrophylla), the spots on the leaves are light gray in color and surrounded by brown or purple fringes. On the other hand, in the Hydrangea quercifolia leaves, the spots on the leaves are angular, dark brown or purple.
Another disease of hydrangeas, manifested in the form of large (up to 2.5 cm in diameter),irregular, dark brown and slightly sunken spots in the leaf blade is hydrangea anthracnoseContrary to to leaf spot, anthracnose symptoms may appear simultaneously on the leaves and flowers at the bottom and top of the shrub. The disease is caused by the fungus Colletotrichum gloeosporioides, which hibernates in dead plant material. Anthracnose thrives in hot (23-32 ° C), cloudy and rainy weather conditions, and the fungus spores spread with splashing water.
Powdery mildew on hydrangea leaves
Gray spots on hydrangea leaves
Garden-grown hydrangeas are attacked by powdery mildewThis disease usually appears in spring and autumn. The development of powdery mildew is caused by soaking the leaves during watering hydrangeas, especially those growing in the shade, and by nitrogen over-fertilization.It is caused by the fungus Erysiphe polygoni which attacks the leaves of hydrangea. As a result of theinfection, the leaves of the hydrangea show gray, mealy spotsthat quickly enlarge to irregular shapes. Over time, the spots turn yellow and dry, and the leaves and tops of the shoots become distorted.
Fighting diseases of hydrangea leaves
In the fight against fungal diseases of hydrangea leaves, regularremoval of infected leaves and their destructionis extremely important, as they are a source of re-infection of the shrubs. The whole shoots strongly affected by the disease should also be removed and destroyed. The following are also very important:
- avoid soaking hydrangea leaves when watering,
- growing shrubs in optimal conditions,
- avoiding over-thickening of the hydrangea bushes.
Forspraying against hydrangea diseases that cause leaf stains , we can use natural and ecological preparations:
Biosept Active- a natural preparation based on grapefruit extract strengthens plants and makes them resistant to diseases, as well as stimulates faster growth and facilitates regeneration of plants damaged by disease. As a preventive measure or after noticing stains on hydrangea leaves, Biosept Active is diluted in water in the amount of 1 ml of the agent per 1-2 liters of water, and then sprayed at intervals of 7-14 days.
Lecitec- an ecological preparation based on natural lecithin. Lecithin strengthens cell membranes and protects hydrangea leaves against the penetration of pathogens causing diseases. To prepare a hydrangea spray, dissolve 25 ml of Lecitec in 8 liters of water. Spraying is repeated several times at weekly intervals.
Chemical protection may be necessary in severe cases.To combat diseases of hydrangea leavesuse fungicides, such as Topsin M 500 SC or SAPROL.
MSc Eng. Agnieszka Lach
