Agapanthus Flowers Dying. Gray mold fungus preys on dying flowers of lily-of-the-Nile. When the blooms begin to fade you can deadhead the flower only and leave the stalk or remove the entire stalk too.
23072020 This is usually more of a concern with deciduous varieties meaning they die back to the ground over the winter. It is believed that this is caused by an as yet unidentified worm which bores down the stem of the plant and subsequently eats the rhizome. They wont provide any foliage-interest over the winter but theyll come back bigger and better the next spring.
Deciduous Agapanthus can be damaged if they go through an extreme freeze that dips below 10-15 degrees Fahrenheit.
How to Prune Agapanthus. Diseases affecting agapanthus are often brought about by overwatering and too much moisture. Agapanthus are known for their large blue drumstick-headed flowers in summer. Beloved for its 4-inch-wide blue or white flowers that tower a foot or more above the foliage agapanthus is an easy-to-grow plant that requires little care.