As long as she is he althy, she requires little care work. But if she becomes ill, action must be taken quickly. Which diseases can affect the star magnolia? How can you recognize them, how can they be combated and prevented?
What diseases can affect star magnolias and how to treat them?
Star magnolias can be affected by diseases such as powdery mildew, leaf spot, scab and fruit tree canker. Powdery mildew appears as grayish-white to yellowish spots, leaf spots as black, angular spots on leaves and petals. Pruning measures, spacing, and nutrient supply can help prevent and treat the diseases.
What diseases can occur
Basically, the star magnolia is not very susceptible to disease. If the site conditions are right, it usually holds up well. If you are unlucky, for example in adverse weather conditions, powdery mildew and leaf spots can affect the plant. In rarer cases, scab and fruit tree cancer occur.
Mildew on the star magnolia
If your star magnolia is affected by powdery mildew, you can tell by grayish-white to yellowish spots on its leaves. Sometimes the shoot tips are curled up. This is powdery mildew, where fungal spores are the problem.
You can proceed in different ways if you have mildew infestation. Either you cut away the affected areas of the star magnolia (does not tolerate radical pruning) or you spray the affected parts of the plant with nettle broth or a saline solution. In general, it is advisable not to use chemical agents to combat the fungal pathogen.
Leaf spots on the star magnolia
The cause of leaf spot is a bacterium called Pseudomonas. It prefers to attack the leaves and petals of the star magnolia. An infestation can be recognized by black, angular rather than round spots on the leaves or petals. Holes appear in the later stages. Eventually the leaves fall off.
To get rid of the bacteria, you should completely remove all of the plant's foliage in the fall and dispose of it safely. Pseudomonas overwinters in the leaves to cause trouble again next year
Why is the star magnolia sick?
There can be several reasons why a star magnolia is affected by diseases. These include, among others:
- Transplanting in the wrong location and at the wrong time
- Nutrient Deficiency
- too alkaline soil pH
- Water shortage
- Stress
- The planting distance from other plants is too small
- windless location
- too dense crown
To prevent this, you should choose a suitable location for the star magnolia from the outset. In addition to partial shade, an airy location is important. Lighten the crown regularly so that water on the leaves can dry quickly.
Tips & Tricks
Star magnolias are sensitive to drought. This weakens them and makes them more susceptible to illness. Prevent this by mulching the root area.