dahlias

Question

Dahlias leaves are turning yellow, but flowers are still in bloom.

Answer 1

Yellow leaves can happen for a number of reasons. When did you last fertilize? Too much nitrogen can eventually cause the plant to yellow and start to die. If you have not fertilized, then underwatering, lack of nutrients or a fungus may be to blame. Increase water a bit, use a balanced fertilizer on the plant and treat it with a fungicide. This should take care of the most common causes of yellowing.

You may also find this article helpful:
https://www.gardeningknowhow.com/plant-problems/environmental/plant-leaves-turn-yellow.htm