The lily is a favorite garden flower for good reason. The genus contains species or hybrids for any hardiness zone in the United States, and few other perennials dominate the summer garden all summer long. Three basic flower types, the trumpet type of the Aurelian or longiflorum lilies, bowl type of the Asiatic, and recurved Turk’s cap of the martagon, provide a variety of forms. Commonly planted varieties provide a summer-long succession of bloom for any garden.
Bloom Time Vocabulary
Longiflorum lilies have classic trumpet-shaped flowers.
The period that a lily — or any flower — blooms is expressed in terms of early, mid or late-season for that genus. The lily season runs from the middle of June through early September. Most garden lilies are hybrids that have specific bloom periods. They are descended from species lilies, some of which are native to the United States and others native to Europe and Asia. Bloom times occur throughout the summer for the dozens of species lilies planted as garden plants in their native ranges.
Species lilies are native wildflowers.
The panther lily, or Lilium pardalinum, which grows in the coastal ranges of California, blooms early and mid-season from mid-May through July. The Turk’s cap, or Michigan, lily, scientific name L. michiganense, on the other hand, blooms mid- to late season, from July through August, over a wide range as far south as Mississippi, north to its namesake, Michigan, west to Oklahoma and east to New York. Another western lily, Humboldt’s lily, L. humboldtii, blooms mid-season in late June and July, as does the eastern Canada lily, L. canadense. The exotic Southern red lily, L. catesbaei, blooms mid- to late July through September along the Southeastern coastal plain. Bloom times and spans vary in areas where species lilies are not native.
Hardy, bowl-shaped asiatic hybrids bloom early to mid-season.
In addition to species like the towering Michigan lily that grows 5 feet tall and blooms through early September, and L. martagon species and hybrid lilies that bloom very early from late May through June, two hybrid lily types grow successfully in USDA hardiness zones 3 to 5. Asiatics, hardiest of the hybrids, bloom in June and early July; newer hybrids extend the bloom into August. Bowl-shaped blooms appear in a broad range of jewel-like colors, many freckled. As plants mature, 3 to 4-foot stems may bear a dozen blooms. Trumpet and Aurelian hybrid lilies produce funnel-shaped flowers on tall stalks from mid- to late summer. Trumpets and Aurelian lilies’ dark or iridescent exteriors add to their drama but they often require winter protection.
Temperate Zone Hybrids
Turk’s cap hybrid with recurved tepals
Less hardy lilies were once limited to pots in flower shops, but when crossed with hardier varieties, they provide variety for temperate-zone gardeners. Longiflorum, sold as Easter lilies, crossed with Asiatics, make "LA’ hybrids, trumpet-shaped, colorful mid-season bloomers. "AO," Asiatic-Oriental hybrids, bloom mid-season. "OT," or orienpets, cross Oriental and trumpets and thrive in warmer zones and bloom from late July through August. American hybrids grow best on the West Coast and are strong mid-season bloomers, bearing spotted, recurved blooms.