Properly cared for, a butterfly bush is resistant to plant diseases. If the flowering shrub is in distress as a result of poor weather conditions or neglect in care, vulnerabilities come to light. There are two diseases in focus. Read here what these are, how the symptoms appear and how to act correctly.
In the case of an infestation of narrow leaves, only a radical pruning usually helps
Bad weather causes downy mildew
As long as your butterfly bush is enjoying sunny summer weather, all is well. In connection with wet and cold weather, crafty fungal spores take advantage of the moment. Downy mildew causes a gray lawn of fungus on the undersides of the leaves, while yellow spots spread on the upper sides of the leaves. How to deal with the common disease:
- Cut off all affected parts of the plant and dispose of with household waste
- Spray the infected butterfly bush repeatedly with a decoction of field horsetail
- Do not administer any more nitrogen-rich fertilizer
- For the water supply no longer sprinkle, but pour directly onto the root disk
- Mulch with bark mulch, leaves or dried grass clippings
Various fungicides that are approved for home gardens are available in specialist shops. These include, for example, Mildew-free from Compo, Universal-fungus-free from Bayer Garten, Kupferkalk-Atempo or Netz-Schwefelit. A sunny, airy location, where rain-dampened leaves can dry off quickly, has a preventive effect.
Narrow leaf disease requires immediate action
If a plant in the garden is infected by a virus, there is little hope of a cure. Rather, the focus is on timely countermeasures to prevent further spread. If the leaves on your butterfly bush are curling, you suspect a tombus virus infection. If a yellowish mosaic drawing also spreads out on the foliage, proceed as follows:
- Prune the shrub back to 20 cm in the early stages of infestation
- Do not administer any more nitrogen fertilizer and take care of it carefully
If curled, yellowish leaves appear on the new shoot, you can no longer avoid clearing. To prevent the viruses from spreading again from the compost, please dispose of the plant remains in the household waste.
tips
Frost damage to a butterfly bush looks confusingly similar to disease symptoms. Do shoots and young leaves appear withered and dead after a frosty night? Then it is not a disease, but frostbite. By radically cutting back the branches down to the healthy wood, the butterfly bush regenerates quickly.