What Is Wrong With My Astilbe?

Do the leaves and flowers have holes in them?

Do the plants look stunted and yellowed, roots have galls on them?

Are the leaves discolored, fine webbing may be present?

Do the leaves have large, ragged holes in them?

Are the leaves covered with white powdery patches?

Does the plant wilts, leaves, and stems may be discolored?

Holes in leaves and flowers are caused by Japanese beetles, pests that can seriously damage plants 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.

If the whole plant looks stunted, the leaves are yellow and spotted and the roots have tiny galls on them the culprits are Root-knot nematodes. Prevent root-knot nematodes by applying chitin or introducing parasitic nematodes to the soil before planting. Solarizing the soil also helps in preventing root-knot nematodes.

Spider mites often cause problems for astilbe. Hose off plants when symptoms first appear. A strong stream knocks mites off plants and may give control. Introduce predatory mites. For severe infestations, spray plants with insecticidal soap or pyrethrin.

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.

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. Any commercial fungicidal spray will protect your plant from further infections.

These symptoms are most likely caused by Fusarium wilt. There is no cure for Fusarium wilt, so the infected plants should be destroyed. Do not plant new astilbe flowers or any susceptible plants to Fusarium wilt in the same spot for several years.

If the roots are damaged the culprits are rodents like mice and voles. The presence of a pet dog or cat often deters rodents. Line planting beds with screen or hardware cloth to keep pests from burrowing around plants.