How-to Guide
How to Grow Garden Lilies
The short answer
True lilies (Lilium) grow from bulbs planted in fall or spring. University of Illinois Extension recommends a planting depth of 6 to 8 inches with plants at least one foot apart; Clemson Extension gives 4 to 6 inches deep and 6 to 10 inches apart for most lilies (Madonna lilies are the exception and are planted shallowly). Both agree drainage is essential — Illinois suggests amending the bed with peat and compost up to one-third each by volume.
Asiatic types flower in early summer with 4-to-6-inch blooms. When clumps get overcrowded, flowering drops off; Illinois says to dig, divide, and replant the bulbs in August before the leaves yellow, or store them in a cool, dry place until spring.
When and how deep to plant
- 1Fall is the classic window — Lily bulbs are typically sold for fall planting; potted lilies from garden centers can go in during the growing season (Illinois).
- 2Plant deep — Illinois: 6 to 8 inches deep, at least 12 inches between plants. Clemson: 4 to 6 inches deep, 6 to 10 inches apart. Deep planting anchors the tall stems and keeps bulbs cool.
- 3Build the drainage in — Amend with peat and compost — up to one-third each by volume per Illinois — because lily bulbs sitting in wet soil rot.
Sun, soil, and water
Clemson lists sun to part shade for garden lilies in well-drained soil. The traditional target is flowers in the sun with roots shaded and cool — mulch or underplanting achieves the same thing.
After-bloom care
Deadhead spent blooms so no energy goes to seed, but leave the leafy stalk standing until it yellows — the green stem and leaves are refilling the bulb. As cut flowers, lilies last as much as 10 days in water with floral preservative (Illinois).
⚠ Lilies are flagged in our safety review for households with cats. Before planting or bringing cut lilies indoors, check Lilium on the ASPCA toxic-plant database or ask your veterinarian — do not rely on general garden advice for this one.
Dividing when bloom declines
Crowding is the usual reason an established lily patch blooms less each year. Illinois Extension's fix: in August, before the leaves yellow, dig the clump, divide the bulbs, and either replant immediately or store the bulbs in a cool, dry place until spring.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- University of Illinois Extension — Plant of the Week: Asiatic Lilies — Planting depth 6-8 inches, spacing at least 1 foot; amend soil with peat and compost up to one-third each by volume; fall planting; flowering drops when overcrowded; divide in August before leaves yellow; early-summer 4-6 inch flowers; 10-day vase life
- Clemson Cooperative Extension HGIC — Summer- and Fall-Flowering Bulbs — Lilies 4-6 inches deep (Madonna shallow), 6-10 inches apart, sun/part shade, well-drained soil, fall or spring planting