Sticky Leaves on Roses and Blackberries: Aphid Honeydew

The clear, sticky substance on your rose and blackberry leaves is honeydew—excrement from aphids feeding on plant sap. Hot weather accelerates aphid reproduction.

Identification

• Look on leaf undersides and new shoots for clusters of small (1/8 inch), soft-bodied insects—green, pink, black, or yellow.
• Ants often tend aphids for honeydew.
• White cast skins may be present.

Control

1. Blast with water: Strong jet knocks off many aphids.
2. Insecticidal soap or neem oil: Thorough coverage, especially undersides. Repeat weekly.
3. Systemic (imidacloprid): Soil drench for season-long control on ornamentals (not for edible berries at harvest).
4. Beneficials: Lady beetles, lacewings, parasitic wasps—avoid broad-spectrum sprays to conserve them.

Outcome

Once aphids are controlled, honeydew stops, and sooty mold (black fungus on honeydew) weathers off. Your plants will recover quickly.