What Is Wrong With My Foxglove?

Do the leaves and/or flowers have holes in them?

Are the leaves covered with white powder?

Do the leaves have large, ragged holes in them?

Are the leaves, stems, and buds distorted and sticky with clusters of small insects?

Do the leaves have white, cottony clusters on them?

Do the leaves have spots on them?

Holes in leaves and flowers are caused by Japanese beetles, pests that can seriously damage foxglove foliage. Adults of these insects devour leaves, stalks, and flowers of nearly 300 plant species. Their larvae feed on the roots of the plants. Handpick adult beetles into a can of soapy water but make sure to wear gloves as Japanese beetles are blister beetles. Apply parasitic nematodes to the soil to limit beetle grub populations. Use pyrethrin powder or neem oil as a last resort.

White, powdery coating on the leaves is caused by a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining any surrounding plants. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed.

Large, ragged holes in the leaves are caused by slugs and snails. Slugs and snails feed on the plant leaves usually at night. To control slugs and snails use diatomaceous earth around your plants. You can also handpick them during the night or use shallow dishes filled with beer as a trap.

Foxglove aphids are pests that feed on other plants but overwinter as eggs on foxgloves. Good gardening practices will slow the spread of foxglove aphids. Remove spent plants in fall to reduce aphid activity in the following years. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

White, cottony clusters on leaves are caused by mealybugs. These tiny insects are covered with a fluffy white coating. They feed by sucking plants sap. They produce sticky substance honeydew which makes leaves sticky. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

If your foxglove leaves have spots they are most likely fungal leaf spots. Fungal leaf spots may be brown, black, or transparent. Remove and destroy all infected leaves. Thin plants and avoid crowding future plantings. Water plants from below. Clean up all plant debris around your flowers to remove overwintering sites.

Some environmental issues or poor growing conditions might have caused your foxglove unhealthy look. Foxgloves enjoy a shady site with rich, moist, well-drained, slightly acidic soil. Plants tolerate full sun, but favor cool weather and need shade in the extreme summer heat. Water regularly to maintain soil moisture. Stake tall cultivars to support flower spikes and plant in a sheltered site.