How to prevent and control hydrangea viral disease? Detailed daily care methods
The hydrangea is native to Japan and the Sichuan area of China. It was introduced to the UK in 1736. In Europe, cultivation is relatively common in the Netherlands, Germany and France, and red, blue, purple and other colored hydrangea varieties can be seen in flower shops. There are also quite a few hydrangeas planted in the ground in small courtyards and in front of buildings. The German company Rampp·Jungpflanzen (RamppJungpflanzen) is a world-famous enterprise producing hydrangeas, and is also the most important breeding and production unit for new hydrangea varieties. Next, the Dutch company Moerheim·Van Waveren and Israel's Yag Nursery are also major hydrangea production enterprises. In Asia, Japan is mainly rich in hydrangeas, and there is a wide variety of hydrangea cultivars in horticultural shops, where many new varieties with strange flower colors can be seen, all expensive and used as household potted ornamentals.
Hydrangea viral disease is also known as hydrangea ringspot viral disease and hydrangea mosaic disease. It has been found sporadically in Beijing, Henan, Hebei and other places. It harms hydrangeas, making the plants stunted, the flowers small and pale in color, and reducing their ornamental value. In some places, horticultural cultivation appreciates its diseased beauty, calling it variegated-leaf hydrangea.
Symptoms: a systemic disease; infected plants are weak all over, and the color of branches, leaves and flower spikes is pale, appearing light green under a layer of pale pinkish-white covering; the leaves are mixed with irregularly shaped pinkish-white patches within the pinkish-green, with clearly defined patch boundaries separated by leaf veins; the leaf margins are white. In early spring and winter in the greenhouse, the diseased leaves are distinctly green and white, and after the arrival of high summer temperatures the color contrast becomes smaller.
Disease occurrence pattern: a viral disease. It occurs sporadically and spreads within the nursery by cutting propagation.
Prevention and control methods
(1) Strict quarantine to prevent spread and expansion.
(2) Do not use diseased plants as mother trees for layering, division or collecting cuttings for propagation. If grown for ornament, a special plot may be set up to propagate diseased plants, but the scope should be strictly controlled.
Care of hydrangeas:
Hydrangea is also known as herbaceous hydrangea and shade hydrangea. It is best to repot once every year in early spring, replacing with new culture soil (half leaf mold and half garden soil mixed with a small amount of sandy soil). When repotting, remove part of the old soil and rotten roots, and prune appropriately.
Hydrangea likes fertilizer. During the growth and development period, apply a decomposed dilute liquid fertilizer once every 15 days. To keep the potting soil acidic, add 100 grams of ferrous sulfate to every 50 kg of liquid fertilizer for watering. Applying 1 to 2 additional applications of potassium dihydrogen phosphate solution during the bud stage will make the flowers larger and more colorful. Hydrangea leaves are large and require a lot of water. Watering should be sufficient in spring to keep the potting soil moist, especially in the hot summer, when even more water is needed. From May to August, it is also necessary to spray water on the leaves once a day or every other day. Because hydrangea has fleshy roots, too much water easily causes root rot, so watering should not be excessive. After rain, promptly pour out any accumulated water in the pot. After September, gradually reduce the amount of watering to make the branches grow sturdy. Before Frost's Descent, move it indoors and keep the room temperature at about 5°C to promote dormancy. Before winter arrives, remove the leaves to prevent them from rotting.