Anemones can be attacked by pests such as aphids, beetles, slugs, and snails. In my experience, diseases like botrytis blight, powdery mildew, and leaf spot diseases can also infect these beautiful flowers. My favorite forms of pest control that work best include horticultural oils, insecticidal soap, and pesticides. In this article, I’ll discuss common anemone pests and diseases and how to deal with them in your garden.
Aphids are small black or green insects that gather on stems or underneath leaves to suck sap from anemones. Plants infested with aphids show symptoms such as black mold, deformed leaves, and stunted growth.
Most aphid infestations can be evicted by blasting plants with a hose. Alternatively, use biological controls, horticultural oils, insecticidal soap, or pesticides. Some natural predators like hoverflies, lacewings, and ladybirds can control aphid populations for you, so encourage them in your garden.
Blister beetles and Japanese beetles can cause severe problems for anemones. Blister beetles have orange or yellow markings on their black bodies, while Japanese beetles have iridescent green carapaces.
If a beetle strips an anemone of its leaves, it can take up to a year for the plant to recover. If you find these beetles on your anemones, wear gloves and squash them. Eliminate beetle larvae using biological controls, horticultural oils, or insecticidal soap.
3. Foliar Nematodes
Foliar nematodes are tiny worms that burrow into anemone leaves to consume plant cells. The main symptom of a nematode infestation is the appearance of angular blotches of discoloration on anemone leaves. These blotches then turn brown and disintegrate, leaving holes in the leaves.
Anemones that are infested with nematodes must be disposed of. Nematodes prefer wet foliage, so always water anemones at the base of the soil to keep the leaves dry. Nematodes can spread between plants, so space out your anemones and remove any surrounding leaf debris.
4. Snails and Slugs
Snails and slugs are common garden pests that can decimate anemones, especially young plants or shoots. These mollusks like moist conditions and are more active after rainfall. If you find large holes in the leaves of your anemones, slugs or snails are probably to blame.
If you spot slugs or snails, pick them off and crush them. Slug or snail pellets are an option but can harm garden wildlife. Control mollusk populations using beer or fruit traps or encourage natural predators like birds, frogs, and hedgehogs.
Whiteflies are another type of sap-sucking pest that are similar to aphids. If you disturb an infested plant, you may be engulfed by large clouds of these small white flying insects. Whiteflies leave deposits of sticky honeydew on anemone leaves, which can lead to sooty black mold.
Whiteflies are easy to spot; in most cases, you can get rid of them by spraying your anemone with a hose. Use biological controls, horticultural oils, or insecticidal soap for larger infestations.
6. Botrytis Blight
Also known as gray mold, botrytis blight is a common anemone infection caused by the Botrytis cinerea fungus. Parts of infected anemones may become covered in clumps of gray mold or experience brown spots on the foliage. Gray mold is more common on anemones growing in wet, humid environments.
As soon as you encounter botrytis blight, dispose of infected plants immediately. Botrytis cinerea can survive on leaf debris during the winter, so clear away any debris surrounding your anemones. Use organic fungicides to eliminate the infection.
7. Leaf Spot Diseases
Various leaf spot diseases can also infect anemones. Fungal spores cause these in humid, wet conditions and will infect anemones that don’t receive sufficient airflow. If anemone leaves develop black or brown spots or unsightly lesions on the stems, you’re probably dealing with leaf spot.
Remove any foliage that shows leaf spot symptoms and treat surrounding leaves with horticultural oils such as neem oil. Water your anemones at the base of the stems to prevent water from soaking the flowers or foliage.
8. Phytophthora Rot
One of the more debilitating diseases that anemones can suffer from is Phytophthora root rot. This infection is caused by spores of the Phytophthora fungus, which cause anemone leaves to droop, wilting, and turn yellow.
Check the roots if you suspect that Phytophthora root rot affects your anemones. Infected plants will have black or brown roots that are mushy and smelly. Cut the infected roots away and safely dispose of the soil, as Phytophthora fungus can survive for years.
Avoid overwatering your anemones, which causes saturated soil conditions that Phytophthora fungi love. Improve the soil’s drainage by mixing in some horticultural sand or grit if necessary.
9. Powdery Mildew
Powdery mildew is a fungal infection that loves hot, dry conditions during the day and cold, wet conditions at night. This infection causes dusty white growths to appear on anemone leaves. Other symptoms include distorted or stunted growth.
Always water your anemones in the morning to avoid leaving them in cold, wet conditions overnight. Allow plenty of space between anemones and other plants to promote airflow. If powdery mildew does occur, use horticultural oils or organic copper fungicides.
10. Sclerotinia Disease
Sclerotinia disease is caused by the Sclerotinia sclerotiorum fungus and causes problems like root rot. The Sclerotinia sclerotiorum fungi can endure in the soil for at least three years, even without a host. Symptoms include white fluffy molds appearing on anemone stems and rotting around the base of the stems.
Remove affected anemones immediately and safely dispose of the plants and the surrounding soil. Keep the ground around surviving anemones clear of other plants and leaf debris. Sclerotinia disease is more common in wet conditions, so avoid leaving anemones in waterlogged soil.
Pesticide and Insecticide Options and Solutions
Horticultural oils such as canola and neem are common in grocery stores or garden centers. These oils work by interrupting the breeding cycles of pests like aphids or whiteflies. Horticultural oils are easy to apply and don’t rely on harmful chemicals.
Insecticidal soap kills insects like aphids by suffocating them or drying them out. You can also make your version of insecticidal soap by mixing dish soap with some warm water.
Biological controls are predatory organisms like mites and worms that feed on pests like aphids or whiteflies. These are environmentally friendly alternatives to chemical pesticides. Choose the proper biological control for the pest you’re trying to combat.
Pesticides and Fungicides
If you can’t eliminate pests or fungal diseases using organic methods, you may have to resort to pesticides or fungicides. Many of these products contain synthetic chemicals that can harm beneficial insects and other wildlife. Try and use organic pesticides and fungicides wherever possible. If you need synthetic products, aim to use them carefully and sparingly.
Managing Anemone Pests and Diseases
The best way to manage anemone pests and diseases is to prevent them from attacking your plants. Try to provide the best possible care conditions to ensure that your anemones are healthy and robust.
Anemones need 6 to 8 hours of full sun every day. Anemones prefer well-draining soils with good aeration, which helps prevent waterlogged soil. Water anemones approximately once per week, but avoid splashing water on the leaves or flowers.
Fertilize anemones twice a year to promote robust and healthy growth. Apply one dose of fertilizer in early spring and another in late spring or early summer. Always give your plants plenty of space between plants and remove any leaf debris around the base of the stems. It’s often prudent to deadhead anemones during the flowering season and cut back as part of your end-of-season care.
To keep your anemones blooming right through the season, it’s important to protect them from pests and diseases. Common anemone pests include aphids, beetles, slugs, and snails. Anemones can also suffer from diseases such as gray mold and powdery mildew. Providing good care conditions can help prevent many of these issues.