What Is Wrong With My Lily Of The Valley?

Are the leaves notched?

Do the leaves have large, ragged holes in them?

Have the stems rotted at the soil line?

Are the leaves spotted or blotched?

Are the leaves spotted, stems blackened at the base and the plant is toppling over?

Have the flowers diminished?

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 plants can occasionally be infected by fungal Crown rot disease. Crown injury and excess moisture during dormancy also increase the chances of infection. Choose well-drained sites. Add organic matter to improve soil drainage. Keep winter mulch away from crowns. Remove and discard infected plants and the surrounding soil. Do not replant lily of the valley in that area for a year or two.

Fungal leaf spot diseases thrive on moist leaf surfaces and cause transparent, brown, or black spots that disfigure leaves. Flecks or black dots, the spore-bearing fruiting bodies surround some fungal spots. Often spots come together to form larger patches of dead tissue. Pick off and discard affected leaves. In severe cases, spray plants with a sulfur-based fungicide every 7 to 10 days until symptoms begin to disappear. Remove dead plant debris promptly from the garden to reduce overwintering spore populations.

Stem rot causes these symptoms. These problems are common when plants are kept in a place where too much shade prevents the leaves and soil from drying out. Remove and destroy infected plants and surrounding soil. Let the soil dry somewhat between waterings, and incorporate organic matter to improve soil drainage. Avoid overwatering and overcrowding. Keep winter mulch away from the crowns to prevent excess moisture.

When lilies of the valley become overcrowded, the flowers become sparse. Simply divide or thin the plants, and next year more flowers will appear.

In late summer, the leaves of lily-of-the-valley normally turn yellow and begin to look a little sickly. They die back every year. Keeping the bed well watered through the hot summer month’s delays this natural process a bit.