The leaves of the delphinium (lat. Delphinium) can look very different, depending on the variety. Some delphiniums have hand-shaped leaves, others are lobed in three parts or even very strongly dissected. What is common to all varieties, however, is that the leaves are very low on the perennial, with only the flower panicles at the top.
Try to keep delphinium leaves dry when watering
Leave leaves on the plant
When caring for delphiniums, you should be careful not to wet either the leaves or the flowers with water. On the one hand, the fine water droplets act as a kind of burning glass in strong sunlight and can cause burns. On the other hand, they also provide a welcome home for moisture-loving bacteria and fungi. Even when cutting back the faded parts in summer, you should only cut off the stems to just above the edge of the leaf. If you cut deeper (and remove leaves at the same time), it will be much more difficult for delphiniums to sprout again.
Identify disease in the leaves
You can see from its leaves whether the delphinium is healthy or not. That is why we are presenting some clinical pictures and their treatment options at this point.
Leaves turn black
As soon as the leaves turn black and their surface bulges, the plant is infected with the bacterial pathogen Pseudomonas delphinii (also known as "bacterial blackness"). On the other hand, brownish to black spots, which later lead to complete discoloration, are an indication of leaf spot disease. Both diseases are highly contagious, which is why infected parts must be removed and disposed of immediately.
Leaves turn yellow
Yellow leaves, on the other hand, are less a sign of disease than a sign of deficiency. If the leaves of the delphinium turn yellow, there is a nutrient deficiency - which, however, can not only be caused by a lack of or insufficient fertilization, but also by root rot caused by waterlogging. However, if only the fertilization is missing, you can make up for it with liquid fertilizer that can be used quickly.
Leaves turn white or gray
Larkspur is very susceptible to powdery mildew, which mainly occurs on hot and dry days (and is therefore also popularly known as "fair weather fungus"). Affected leaves appear coated with white or gray flour. Immediately cutting back affected parts of the plant and preventive treatment with a decoction of herbs or milk helps against powdery mildew. As a rule, home remedies help very well with powdery mildew.
tips and tricks
For mildew treatment with milk, mix water (boiled and cooled) with full-fat UHT milk in a 1:1 ratio. Mist the plant with the mixture every two to four days on sunny days for at least two weeks.