Depending on the variety, Delphinium leaves can look quite different. Some are hand-shaped, while others are deeply lobed or divided into three parts. One thing all Delphiniums have in common, though, is that their foliage is concentrated at the base of the plant.
Pro Tips for Leaf Care
When you’re out in the garden with your watering can, try to keep the water off the leaves and flowers. Those water droplets can actually act like tiny magnifying glasses in the hot sun, leading to leaf scorch. Another golden rule: don’t prune away healthy green leaves! You should only trim back faded flowers by cutting just above the foliage line. Avoid cutting any deeper than that, because the plant needs those leaves to gather energy for its next bloom cycle.
How to Spot Trouble Early
Your Delphinium’s leaves are like a health monitor—they’ll tell you pretty quickly if the plant is struggling with pests or disease. Keep a close eye out if you notice the leaves turning any of these colors:
- Black
- Yellow
- Gray or White
Treating Discolored Leaves
If you notice the leaves curling up and turning black, you’re likely dealing with “Bakterienschwärze” (bacterial leaf spot), caused by *Pseudomonas delphinii*. If you see brown to black spots instead, it might be a different fungal leaf spot disease. In either case, you need to act fast and remove the infected parts immediately, as both issues can spread quickly to your other plants.
Yellow leaves are usually a cry for help regarding nutrients. It could be a simple lack of fertilizer, or it might be root rot caused by “wet feet” (standing water). Check your soil drainage if things are looking a bit yellow!
If you see a gray or white powdery coating, your Delphinium has likely caught a case of Powdery Mildew. This fungus loves hot, humid weather. To fix it, trim off the affected leaves right away and treat the plant with a simple DIY spray. Just mix equal parts whole milk and water (boil and cool the water first). Spray the plant every two days for about two weeks, and you should see a big improvement.
