Lily of the valley is a bright, decorative woodland plant, native to Europe, North America and Asia. This plant bears pink and white hanging flowers on firm reed-like stems and survives down to U.S. Department of Agriculture Hardiness Zone 2. To bloom and display its flowers, though, it requires certain conditions.
Lily of the valley is a perennial and may live for many years, but it still follows a standard growing schedule. It blooms in mid- to late spring and holds its blooms into summer. Lack of blooms in the fall to winter indicates natural plant dormancy and is not a reason for concern.
Lily of the valley tolerates some shade, and likes moist, cool conditions better than hot, dry ones. Re-create a woodland atmosphere with filtered or indirect sunlight to encourage better blooming. Don't plant lily of the valley in deep shade, though, as this also restricts blooming.
Soil and Nutrition
Lily of the valley does best in loose, quick-draining and slightly alkaline soil. Mix organic compost or leaf mold into planting sites every spring for drainage and nutrition, but don't use fresh manure. Feed lily of the valley with gentle organic or low-nitrogen 5-10-5 fertilizer in the spring to encourage growth and blooming. Carol Klein of "The Telegraph" notes that high nitrogen content from fertilizer or manure leads to lack of flowering.
Lily of the valley requires adequate moisture content to produce and hold blooms, and won't bloom in dry or hot soil. Increase watering to 2 inches of water every week to keep the plant growing and blooming. Lay 2 inches of organic mulch on the soil around the plant to maintain soil moisture and protect the plant's roots.