Hydrangeas are popular garden shrubs, known for their large, colorful blooms. While hydrangeas do not directly attract ants, their presence indicates an underlying issue: other garden pests. Ants are not interested in the hydrangea plant itself, but rather a sugary byproduct produced by these other insects.
Do Hydrangeas Directly Attract Ants?
Hydrangeas do not directly attract ants. They do not produce nectar or possess strong scents or chemical compounds that ants actively seek for foraging. Any observed ant activity on a hydrangea is a secondary issue, indicating another underlying factor.
Ants are driven by the search for food, particularly sugar. Hydrangeas do not naturally produce large amounts of accessible sugar. Their presence signals a different food source, commonly found in many gardens.
The Real Reason Ants Are on Your Hydrangeas
Ants are found on hydrangeas due to honeydew, a sugary, sticky substance excreted by sap-sucking insects. Common culprits include aphids, scale insects, and mealybugs. These pests feed by piercing plant tissues and extracting sap, which is rich in sugars. They then excrete the excess sugar as honeydew. Ants “farm” these pests for their honeydew, protecting them from predators to ensure a continuous supply. The presence of ants on your hydrangea is a strong indicator of an infestation of these pests.
Identifying Pests on Your Hydrangeas
Discovering the source of honeydew requires a close inspection.
Aphids
Aphids are tiny, pear-shaped insects, often green, yellow, black, or brown, clustering on the undersides of leaves and new, tender growth. Distorted or yellowing leaves can signal aphid feeding.
Scale Insects
Scale insects appear as small, immobile bumps on stems and leaves, resembling part of the plant. They can be dome-shaped or oyster shell-shaped and vary in color.
Mealybugs
Mealybugs are small, oval insects covered in a white, cottony, waxy coating, found in leaf axils or on stems. Both scale and mealybugs suck sap and excrete honeydew, leading to sticky residue and sometimes sooty mold development on leaves.
Managing Ants and Pests
Addressing ants on your hydrangeas primarily involves eliminating their food source: the honeydew-producing pests.
Aphids
For aphids, a strong stream of water from a garden hose can dislodge them from the plant, particularly from the undersides of leaves. This method is effective for early or small infestations. For more persistent aphid problems, insecticidal soap or neem oil can be applied, which work by suffocating the pests. Ensure thorough coverage of all affected areas.
Scale Insects
Scale insects can be challenging to remove, but light infestations may be scraped off manually with a soft brush or fingernail. Horticultural oils can be effective, especially when applied during the plant’s dormant season, as they suffocate the insects.
Mealybugs
For mealybugs, alcohol-soaked cotton swabs can be used to dab individual insects, or insecticidal soap and neem oil can be applied for larger infestations. Introducing beneficial insects like ladybugs and lacewings can also help control aphid and scale populations naturally, as they are natural predators.
Preventing Future Infestations
Proactive measures can significantly reduce future pest and ant infestations. Regular inspection of your plants is a simple yet effective preventative step, allowing for early detection and intervention. Maintaining good plant health through proper watering and fertilization also strengthens hydrangeas, making them less susceptible to pests. Ensuring adequate air circulation by appropriate plant spacing and pruning can also deter pests. Encouraging natural predators by avoiding broad-spectrum pesticides and planting nectar-rich flowers nearby can create a balanced garden ecosystem that naturally keeps pest populations in check.