If the lavender has yellow leaves with more or less large brown to black spots, the plant is infected with the dreaded leaf spot disease. This is sometimes referred to as shotgun disease because the leaves can appear as if they have holes in them.
Why is my lavender turning yellow and getting spots?
If lavender turns yellow and has brown to black spots, the plant is suffering from leaf spot disease. This is caused by fungi such as Septoria, Ascochyta or Alternaria and can lead to plant death, especially in humid conditions, unsuitable locations and lack of light.
Causes of leaf spot
Various fungi of the genera Septoria, Ascochyta or Alternaria cause this disease, which is noticeable by a yellowish discoloration of the leaves and reddish, brown or black spots. Like all fungal diseases, leaf spot spreads quickly and ultimately leads to the death of the plant. Such fungi primarily attack weakened plants that are too moist, too crowded or in an unsuitable location. Fungal infestation of lavender is particularly common in cold and humid summers.
Prevent fungal infestation
Since fighting a fungal disease is difficult, prevention is an important measure. That's why you should buy lavender
- too much moisture, especially waterlogging,
- planting too close together
- planting on unsuitable (loamy or peaty) soils,
- intensive fertilization, especially with nitrogen
- a false wintering
- and lack of light (partly shaded or shady location)
avoid. By the way, the fungi survive even harsh winters because they simply hibernate on the plant or leave spores behind. They can then continue to work the following year and let the lavender die.
Combat is usually only possible by cutting away large areas
As soon as the leaves, and sometimes even the stems, of the lavender are infected, you should tackle the fungus with hedge trimmers. Cut the lavender back vigorously down to the he althy and not yet infected parts. However, you should avoid cutting back into the wood, as the plant will then usually no longer sprout. The tool must then be carefully disinfected to kill any remaining spores. If you don't want to harvest the plant, you can also use a broad-spectrum fungicide.
Tips & Tricks
If, on the other hand, the lavender turns brown and looks like it has dried out, then root rot caused by waterlogging or incorrect watering is usually the cause.
