Hellebore Pest Problems
Hellebore plants are generally vigorous and healthy, and they are not particularly susceptible to bug damage. However, there are a few bugs that eat hellebores. One to watch for is aphids. They can munch the hellebore foliage. They are not very serious as pests of hellebore, however. Just wash them off with hose water. Other bugs that eat hellebores are called leaf miners. These bugs dig into the leaf surface and cause “mined out” serpentine areas. That doesn’t add to the attraction of the plants but doesn’t kill them either. Cut off and burn affected foliage. Slugs can eat holes in hellebore leaves. Pick these hellebore plant pests off at night. Alternatively, attract them with bait traps using beer or cornmeal. Vine weevils are also bugs that eat hellebores. They are black with yellow markings. You should pick them off the plant by hand. Don’t worry about rodents, deer, or rabbits as potential pests of hellebores. All parts of the plant are toxic, and the animals won’t touch it.
Fungal Hellebore Plant Pests
In addition to the bugs that eat hellebores, you also have to watch for fungal hellebore pest problems. These include downy mildew and hellebore leaf spot. You can recognize downy mildew by a gray or white powder that forms on the leaves, stems, or even flowers. Apply sulfur or a general systematic insecticide every two weeks. Hellebore leaf spot is caused by the fungus Coniothyrium hellebori. It proliferates in damp conditions. If you see your plant foliage damaged by dark, circular blotches, your plant may have been infected. You’ll want to act quickly to remove and destroy all infected leaves. Then spray with a Bordeaux mixture every month to prevent the fungus from doing more damage. Fungal hellebore problems also include botrytis, a virus that thrives in cool, damp conditions. Recognize it by a gray mold covering the plant. Take out all diseased foliage. Then avoid further infection by watering in the daytime and keeping water off the plants.