Dayflowers are pretty but recall something sad

The cheery blue color of dayflowers (Commelina communis) — so named because each flower lasts but a day — does nothing to dispel some pity I feel for them.

Not that the petals cry out for sympathy. You have to get fairly close to the plant, or really stop and look at it, to even see its blossoms. Its stems and leaves, though, are bold, seemingly ready to gobble up any piece of ground they can grab with their succulence and lushness.

Aggressive growth coupled with almost inconspicuous flowers could categorize any plant as a “weed.” And many species of dayflower are considered just that, especially in parts of the South and Southwest. But name calling is not what stirs up my sympathies for this plant.

The Brothers Commelina

Take an even closer look at a dayflower. Zoom in on the flower, and below the two prominent, azure petals you’ll see a third petal, pale compared to the other two and much smaller.

The petals are what give dayflower its botanical name. Carl von Linnaeus, the founder of our system of plant nomenclature, gave dayflowers the botanical name Commelina to honor two 18th-century Dutch brothers who were stars in botany at the time. But there was a third brother too, less successful than the other two and represented by the dayflower’s pale, relatively inconspicuous petal. More generous accounts say the third brother died young, before he was able to leave his mark on botany. At any rate, what a sad thing to be immortalized for one’s deficiencies.

Good kin for dayflower

Despite being called a weed and memorializing someone’s lack of accomplishment, dayflowers keep good company. Among their kin is the popular houseplant called wandering Jew, appreciated for the way its drooping, purple-tinted stems impart a tropical lushness to heated homes in the winter.

Another dayflower relative is Moses-in-a-boat, with lurid purple, spiky leaves. The name comes from the fat flowers that nestle down in the folds of the leaves. Moses-in-a-boat is sometimes grown as a houseplant, but my favorite sight of it was outdoors in the tropics, grown as ground cover to create swathes of purple that contrasted with adjacent beds plush with lime green baby’s-tears.

Among outdoor plants in colder regions, dayflowers’ best known relatives are spiderworts. Spiderworts look much like dayflowers, except the flowers are larger and have only two petals.

And some more memorable kin

Linnaeus named spiderworts for other prominent botanists, the Tradescants. Naturalist and plant collector John Tradescant I, often referred to as the “father of English gardening,” was head gardener to King Charles I. His equally accomplished son, a royal gardener as well, was among the first European plant explorers to the New World. Like dayflowers, spiderworts can spread aggressively.

I’m not going to call dayflowers “weeds” in my garden. Their lush greenery is welcome and so far under control. And a close, close look at any of the green-hooded flowers reveals hidden beauty. From the base of the two prominent, blue petals arise three tiny sepals (modified petals), each like a flower itself with three yellow lobes and a dark maroon center. From below these sepals swoop forward two anthers, behind which — and not to be missed — is that third, pale petal.