There are not many diseases that affect hollyhocks, but mallow rust can be very hard on it. While it is particularly unsightly on old plants, young hollyhocks can also suffer from it.
How can I prevent mallow rust on hollyhocks?
To prevent mallow rust on hollyhocks, you should choose a sunny, not too moist location, maintain sufficient planting distance, water regularly, fertilize if necessary and remove the first leaves in spring and spray the plant with horsetail broth or compost.
How does mallow rust manifest itself in hollyhocks?
A fungus, Puccinia malvearum, is responsible for mallow rust. It causes ugly yellow spots to appear on the top of the leaves. On the underside of the leaves, these spots are reddish and raised, like small pustules. Mallow rust often occurs in spring. The fungus can even overwinter in the plant.
How to prevent mallow rust
Prevent mallow rust before you plant your hollyhocks. Choose the location carefully. It should get as much sun as possible and not be too humid. Plant the hollyhocks at a sufficiently large distance from the neighboring plants, it should be approx. 40 cm.
Proper care also contributes to prevention. Water your hollyhocks regularly, especially in summer, during the flowering period, even daily if necessary. However, make sure that there is no waterlogging. If the soil is too firm, you can loosen it up a little and mix in a little sand or gravel. If the soil is poor, fertilize your hollyhocks once or twice a month.
It is often recommended to cut off the first green leaves in spring, as rust strikes particularly frequently at this time. Pruning in the fall is also helpful. Although the above-ground greenery disappears in winter, the rust fungus can spread unhindered while it rots. You can spray your hollyhocks with a broth made from horsetail or with compost broth.
The most important tips against mallow rust:
- prevent in good time
- sunny, not too humid location
- sufficient planting distance
- water regularly
- fertilize in nutrient-poor soil
- remove the first leaves in spring
- Spray with horsetail broth or compost broth
Tip
If you have discovered the first signs of mallow rust on your hollyhock, then you should react quickly, the fungal spores are very robust and persistent.
