What Is Wrong With My Crocosmia?

Are there any brownish-yellow or blackish-brown spores on the leaves?

Are the leaves yellowing, wilting and, dying?

Are the leaves discolored, fine webbing may be present?

Are the leaves curled and distorted?

Do the leaves have large, ragged holes in them?

Are the leaves covered in coarse stippling and may appear silvery?

Gladiolus rust mostly attacks gladiolus, but occasionally this plant gets infected too. When infected, the leaves of the plant will show brownish-yellow or blackish-brown spores. Make sure to water the plant at ground level to protect the leaves. Spray leaves with sulfur early in the season to prevent rust or to treat mild infections.

Yellow leaves that wilt and die usually indicate Rhizome or Bulb rot. This fungal disease occurs in poorly drained, overly wet soils. Choose well-drained sites and add organic matter to improve drainage. Remove and destroy infected plants. Solarize the soil before replanting.

Spider mites are known to cause problems for crocosmia. 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.

Distorted and curled leaves are caused by aphids. These tiny insects cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

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.

These symptoms may indicate thrips. Thrips are tiny, yellow to black flying insects. Severely infected plant parts should be removed and destroyed. Control thrips by introducing lady beetles or lacewings, their natural predators. Insecticidal soap helps in severe infestations.

If the leaves and flowers have been eaten the culprits are Japanese beetles, pests that can seriously damage 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.