COMMELINA. Dayflower. The Americas and tropics elsewhere. These are somewhat surprising perennials and annuals, related to Tradescantia but having irregular flowers. They may be tuberous or simply rhizomatous, in either case often making substantial colonies over time. Their stems are leafy and usually erect, with broad or narrow, usually smooth and glossy leaves. Borne in bracted clusters at the shoot tips are small three-petalled flowers, the two upper petals equal, the lower usually smaller and differently shaped, providing a landing pad for pollinating insects. The flowers last only a day (often less), but they are quickly replaced by younger buds in the cluster. The following are both winter-deciduous. They thrive in sun or light shade near the coast, light shade inland, in most soils with moderate to regular watering. Their hardiness is as shown.

coelestis. Central and South America. This is one of the more robust species, with tightly clustered, erect stems up to 3’ high. The bright green, lance-shaped leaves are up to 6" long. It flowers over a long period in summer, producing a succession of bright blue 1" blossoms. Hardy to 20^oF., possibly less.

dianthifolia. This is a native of the southwestern U.S. and Mexico, where it is often found in drier circumstances than other dayflowers. It makes small clumps, with slender stems 6-12" high. The leaves are quite narrow, giving it a deceptively delicate appearance. It flowers from late spring to fall, with ½” blossoms, the upper petals bright blue, the lower petal quite reduced and paler. Where it is at home, it may self-seed prolifically, though the seedlings are easy to remove. Hardy to 0-10^oF.