When to Plant Lilies

The rule: early fall, with spring as a second chance

Lilies are hardy bulbs that stay in the ground year-round, so unlike dahlias or gladiolus, they can go in either before winter or after it. Most extension advice favors early fall. Iowa State calls it an excellent time to plant Asiatic, Oriental and other garden lilies. South Dakota State plants in spring or early fall, and divides established clumps in early fall, typically early September.

The reason is root growth. Planted in fall, the bulb has several weeks in cool, moist soil to grow roots before the ground freezes, and it starts spring already established. South Dakota State stresses giving new lilies time to root before freeze-up. Illinois Extension makes the same case for fall perennials in general: plant about six weeks before the first frost, while the soil still holds summer warmth.

That puts the fall window in the dates for your zone above at about six weeks before your average first frost up to the frost itself.

Spring planting

Spring works if you missed fall or found bulbs for sale in spring. South Dakota State and Nebraska Extension plant lily bulbs after the danger of frost has passed, which is what the spring dates above show: from the last frost to about two weeks after.

One caution: spring bulbs often have a shoot already growing, and South Dakota State warns it is fragile and easily broken. Handle the bulbs gently and don’t force them into the hole.

Potted lilies from a garden center are the most flexible. Iowa State plants them in spring or summer at the same depth they grew in the pot.

Timing by region

Cold North and the Plains (zones 3 to 5). South Dakota State plants in spring or early fall and divides clumps in early September; give fall-planted bulbs time to root before the ground freezes. Mulch new plantings with a few inches of material for winter. Asiatic lilies are the hardiest group, rated to zone 3 or 4 by Colorado State; Oriental and trumpet lilies are said to survive zone 4 only with heavy mulch.

Midwest and Mid-Atlantic. Iowa State favors early fall. In Maryland, University of Maryland Extension prefers late fall. Illinois Extension notes lilies can go in during fall or early spring.

The South. Most garden lilies are rated only to zone 8, and NC State notes that Martagon types don’t suit hot, humid climates. Where you do grow them, plant at the usual fall or spring times, in well-drained beds with mulch to keep the roots cool.

Florida. UF/IFAS suggests planting a potted Easter lily outdoors after the danger of frost has passed, in a sunny, well-drained spot. It will usually bloom naturally in summer rather than at Easter. Mulch heavily over the bulbs for winter protection.

Planting too early or too late

Too late in fall. Bulbs planted right before the ground freezes have little time to root. Plant them anyway if the ground is workable. If bulbs must be held, NC State suggests keeping them in moist peat at about 35°F. Cover late plantings with several inches of mulch.

Too early in spring. South Dakota State and Nebraska both wait until frost danger has passed before planting lily bulbs in spring. There is little to gain by going earlier, since fall is the time for early root growth.

For planting depth, soil and care, see how to grow lilies.