Coneflowers (Echinacea) are treasured garden staples known for their drought tolerance and vibrant, daisy-like blooms. Their popularity, however, also makes them a frequent target for a variety of pests that diminish their aesthetic appeal and health. Identifying the culprit responsible for the damage is the first step toward effective treatment. Signs of feeding range dramatically, from clean cuts near the soil line to skeletonized leaves or distorted flowers, each pointing to a different pest. Understanding these distinct patterns is key to successfully protecting your plants.
Large Herbivores: Identifying Damage by Mammals
Damage from larger mammals typically involves the removal of significant plant material, leaving behind distinct evidence of their feeding habits. Deer tend to browse on the plant from a higher vantage point. Their lack of lower incisors results in a characteristic ragged, torn edge on the stems and leaves they consume, rather than a clean cut. Deer often target young growth and buds first, but will also eat mature flowers and foliage when other food sources are scarce.
Rabbits, conversely, prefer young shoots and seedlings, and their smaller size means they feed closer to the ground. They leave a very clean, 45-degree angled cut on the stems, similar to a cut made by sharp shears. If entire stems or emerging leaves are severed just above the soil line, rabbits are the likely culprits, often damaging newly planted coneflowers. Groundhogs (woodchucks) are less selective and can consume entire plants or clear out large patches quickly. Their feeding is characterized by the sheer volume of material removed, often leaving behind little more than stripped stalks.
Insect Pests: Identifying Damage by Bugs
Insect damage is often localized and specific, providing clear clues about the tiny culprits at work. Japanese beetles are easily identifiable by their metallic green head and copper wings. They feed by chewing between leaf veins, resulting in “skeletonized” leaves where only the lacy network of veins remains. They also consume flower petals, disfiguring the blooms, and typically feed in groups starting at the top of the plant.
Sap-sucking insects like aphids and whiteflies extract plant juices, causing leaves to yellow, curl, or become stunted. Aphids, which can be green or black, excrete honeydew, a sticky substance that leads to the growth of black sooty mold on the foliage. Whiteflies, tiny insects with yellow bodies and white wings, congregate on the undersides of leaves, causing leaf drop and reduced plant vigor.
Eriophyid mites are nearly microscopic and damage plants by feeding inside the flower buds. This results in severely stunted growth and distorted flowers, sometimes appearing as tufts of green, rosette-like growth emerging from the cone. Caterpillars and slugs leave behind large, irregular holes in the leaves, often consuming entire sections of foliage.
Leafhoppers are pale green insects that suck sap, leaving behind white stippling on the leaves. Their most significant impact is as carriers of diseases like aster yellows. Aster yellows is a serious, incurable disease that causes green, twisted, and stunted flower heads. Infected plants must be removed immediately to prevent further spread by these leafhoppers.
Practical, Targeted Elimination Strategies
Control measures should be tailored precisely to the identified pest to ensure maximum effectiveness. For large herbivores like deer, taste-based repellents containing putrefied egg solids or capsaicin can be applied directly to the foliage. Scent-based repellents, such as those with ammonium soaps, signal the presence of a predator and must be reapplied frequently, especially after rain. Temporary fencing, such as wire cages or chicken wire enclosures around young plants, provides a physical barrier until the coneflowers mature.
Targeting Japanese beetles involves direct intervention, with the most effective method being hand-picking the adults. They are less active in the early morning, making this the best time to gently dislodge them into a jar of soapy water to drown. Pheromone traps should be used with caution and placed far away from the plants you are trying to protect, as they can attract more beetles than they catch.
For sap-suckers like aphids and whiteflies, a strong jet of water from a hose can physically knock them off the plants, especially when directed at the undersides of the leaves. If the infestation is heavy, horticultural soap or neem oil can be applied, as these smother the insects on contact. These treatments must be thoroughly sprayed directly onto the pests themselves.
Addressing eriophyid mites involves removing and destroying the distorted flower heads before the mites can spread. The infected material should be placed in the trash, not composted. Specialized treatments like horticultural oil can be applied early in the season before the flower buds open to reduce mite populations.
Long-Term Habitat and Prevention Methods
Long-term management focuses on cultural practices that strengthen plant health and create a less appealing environment for pests. Ensure coneflowers are planted in well-draining soil and receive adequate sunlight, typically at least six hours daily. This promotes robust growth that naturally resists pest damage. Proper watering, especially during dry periods, is important, as healthy plants tolerate minor feeding better than stressed ones.
Strategic planting of companion plants can actively deter certain pests. Strongly scented herbs like catnip, oregano, and anise hyssop can be intercropped with coneflowers, as their odors act as natural repellents for grazing mammals. Planting garlic or chives nearby can also help deter Japanese beetles. Introducing beneficial insects, such as ladybugs or lacewings, provides biological control, as these predators feed voraciously on aphids and other soft-bodied pests.
Finally, good sanitation, including fall cleanup and the removal of garden debris, eliminates overwintering sites for pests like leafhoppers. This practice reduces the risk of disease transmission in the following season.