4-5' × 3-4' COPF intro, Alberta, Canada.
A “blizzard” of sweet citrusy fragrance from pure-white slightly cupped 4-petaled blossoms for up to four weeks in late spring, after the lilacs fade. A spray of golden yellow anthers attractive to bees and butterflies accents each flower. Medium-sized coarse upright loosely arching shrub. Species was named after Meriwether Lewis who noted it in 1806 during the Lewis and Clark Expedition.
Prefers moist rich well-drained soils but will grow well in most conditions. Full sun to partial shade. Since blossoms form on prior year’s growth, best to prune after flowering. Similar to old-fashioned European Philadelphus coronarius, but this species is native to North America. William Cullina, plant curator emeritus at the Coastal Maine Botanical Gardens calls it “our most ornamental Philadelphus species.” Zone 3.