We’ve had plenty of rain this year, so while we were gone on vacation, the plants around the house continued to grow. One of them, the Asiatic dayflower, has been particularly busy. The plants have sprawled across the ground and climbed over their neighbors. Bryan pulled bales of it out. It’s another of the many invasives that thrive here.
It has round, smooth branching stems that grow up to four feet long. Every few inches there’s a leaf. The leaf is long and narrow, with its base wrapped around the main stem instead of standing on its own stem. Where the leaf and the main stem meet near the tip of the branch, a tiny blue flower may be present. The flowers only last for a day or less, giving it the name dayflower. The flower has two blue petals positioned like Mickey Mouse ears, and one tiny white petal. The flower is less than an inch across and sports bright yellow stamens that attract bees. After the flower blooms, it sets seeds. Each fertilized flower results in two seed capsules, each containing two seeds. The plants are annuals, dying back when the frost comes, but all these seeds will produce more Asiatic dayflower plants next year.
As its name suggests, the Asiatic dayflower (Commelina communis) is not native to North America. It’s native to—surprise—Asia–specifically East Asia. It was probably introduced to North America as a garden plant or ground cover.
The flowers are fleeting, but they have a very long history in Japan and Korea because of their blue color and medicinal properties.
True blue pigment is rare in nature. Many natural blues are created with light reflection mechanisms as in birds’ feathers rather than with pigment. Blue dye can be extracted from indigo, but it takes a complex and specific process to get the blue. A few flowers, including the hydrangea and the Himalayan poppy do have blue pigments, and the Asiatic dayflower is another of these unusual flowers. For centuries, Japanese farmers raised dayflowers as a crop and harvested these tiny blue petals to make blue dye. They called the plant dewflowers presumably because they had to pick the flowers in the early morning just after dawn when the dew was still on them. The flowers were then crushed, squeezing out the blue. It would take a whole lot of those teeny flowers to get much blue pigment, and what they got was susceptible to deterioration in heat or humidity. But it was truly blue. As early as the 11th century, Japanese artists used the blue dye on their woodblock prints. The dye was also used to create designs on kimonos and other textiles. It produced a slate blue color when fresh or well preserved. If it was exposed to humidity, though, it turned a sickly yellow-green. To preserve the dye, a certain kind of paper was soaked in it and then dried. Artists could wet the paper and liquify the dye for use.
The Asiatic dayflower has a history of use in medicine as well. In Korea, it was traditionally used as a diuretic and to treat sore throats, enteritis, obesity, and diabetes. In Japan, it was used to treat fevers.
The flowers, leaves and young shoots are all edible and can be used to garnish salads or lend a sweet note as a pot herb. In Korea the flowers are used to garnish desserts and rice cakes.
The dayflower has also found its way into literature symbolizing the ephemeral nature of life and beauty or, in a traditional Japanese fable, a fickle lover.
The Asiatic dayflower, also known as blue dayflower, spiderwort or mouseflower, is resistant to herbicides like glyphosate. It provides both nectar and pollen to tiny bees and a tasty salad of greens to white-tailed deer. It also provides a home for a quarter-inch-long six-spotted beetle called Neolema sexpunctata. This little orange beetle has six black spots on its back and black legs and antennae. It lays its eggs on the dayflowers’ leaves and both larvae and adult beetles feed on the leaves. Birds like mourning doves, bobwhites and red-wing blackbirds find the seeds palatable. Clearly this invasive foreigner has made a place for itself on Owl Acres.
Photo by Author. Alt text: Karen holds a green sprig in front of her red shirt. The two intensely blue petals of today’s Asiatic Dayflower peek out from the terminal bud. Yesterday’s flower has set its seed capsule at the next node down.