When it comes to plant diseases, the buddleia is quite resistant and remains he althy as long as it feels comfortable in its location and is well cared for. However, waterlogging in particular - for example due to persistent bad weather - can quickly lead to an infection. In addition, the wood, which is only partially hardy, often freezes back severely in cold winters, but will sprout again after pruning.
What diseases can affect the buddleia?
Freeze damage and downy mildew can occur with buddleia. Frost damage usually affects shoots, which can be cut back in spring. Downy mildew appears as white fungal growth and yellow spots on leaves and should be treated quickly by removing affected parts and applying fungicidal measures.
Identify and treat frost damage
Frost damage probably occurs on every buddleia. In particular, the shoots of Buddleja davidii, which is considered to be fairly hardy, freeze back quickly in the event of frost. This is not a problem as long as the roots of the bush are not affected. In early spring (around the end of March) simply cut back the frozen parts of the plant, if possible down to the he althy wood. Using a thumbnail test, you can quickly determine which parts of the bush are still alive - if the layer underneath the bark is still green, the plant sap is still flowing here. After pruning, the buddleia will most likely sprout again.
Problematic in wet summers: downy mildew
More problematic is downy mildew, which occurs frequently, especially in wet, rainy summers. This is a fungal disease that manifests itself as a white-grey fungal growth on the underside of the leaves and yellow spots on the upper side. Young shoots can also be affected. In the event of an infestation, it is important to act as quickly as possible to prevent it from spreading:
- Cut off all affected plant parts.
- Do not dispose of them in the compost, only with household waste.
- Spray the bush with a home-made horsetail decoction.
- Stop applying nitrogen-containing fertilizer.
- If there is a severe infestation, fungicides from specialist retailers approved for private gardening can help.
Prevent downy mildew by only watering the buddleia over the root disc when necessary and not watering it. An airy location with a sufficiently large planting distance can also help, as the leaves dry more quickly after a rain shower.
Tip
Of course, the buddleia is also attacked by pests if it is weakened by incorrect care or an unsuitable location. Aphids, leaf miners and gall mites in particular feel comfortable on such a plant. You can prevent this by setting up an insect hotel with beneficial insects near the flower bushes.
