Mallow rust is an insidious fungal disease that can affect hollyhocks. To prevent the plant from dying, mallow rust must be combated immediately.
Hollyhocks (Alcea rosea) are basically easy to care for and undemanding. They resist most plant diseases. However, mallow rust can occur. This is a fungal disease that not only looks unsightly, but can also cause the leaves and stems to die off. Mallow rust spreads further via fallen leaves. Before you can fight the fungus with biological or chemical means, you first have to recognize it.How to recognize mallow rust on hollyhocks
Mallow rust can break out as early as spring when the first leaves form on the hollyhocks. The leaves get yellow spots on the upper side, the underside of the leaf is affected by red-brown pustules. Later, the leaves become wilted and brown and fall off. Take a close look at young plants before buying, even small spots on the leaves can indicate mallow rust.
As soon as you notice an infestation, remove the affected leaves immediately. Please do not throw it in the compost or leave it on the ground - otherwise the fungal spores will continue to spread unhindered.
There are effective measures to combat it, and you can also prevent it. A generous distance between the individual plants is good, as is a sunny location. Regular application of fertilizer strengthens the plant and increases its resistance.
Fight mallow rust biologically
➜ Making dung with ferns
A natural herb spray that you can make yourself helps against mallow rust. For this you need well-developed fronds of male fern or bracken. Prepare the fern with rainwater (quantity ratio: one kilogram of fern to ten liters of water) and leave the mixture to stand until liquid manure has formed after three days. Spray the entire plant with the undiluted liquid manure. Don't forget the underside of the leaves. The treatment is repeated after about two to three weeks.
➜ Use Garlic Tea
You can also achieve good results with garlic tea. need for thata good handful of garlic cloves, coarsely chop them with their skins on and pour boiling water over them. Let the infusion stand for a few hours, then you can spray your hollyhocks with it.
Fern manure and garlic tea are absolutely harmless to the plants and also have a preventive effect.
➜ Bio-based antifungal agents
Biologically based antifungal agents are available in stores. The active ingredients against the fungus consist of herbs, minerals and sulfur. If the mallow rust does not go away, you can resort to chemicals and use fungicides. But keep in mind that chemistry is not necessarily he althy.
For hollyhocks that are grown outdoors, there is a risk that the fungal spores will survive in the soil. If possible, change the planting location next year!
Summary:
- Sunny location with enough space between the plants
- Fertilize regularly, observe leaves
- Biological control with fern manure or garlic tea
- Chemical control with fungicides
- Dispose of infested plant parts in household waste