The showy white or light pink, funnel-shaped flowers of the wild morning glory are abundant along roadsides right now. Maybe, like me, you think to yourself as you’re driving around or on a walk, “I’d like to find out what kind of wildflower or plant that is when I get home” and then later forget about it until you see them again. So, here to help you with at least one of those flowers, I will provide some information on this pretty native wildflower.
The scientific name is Calystegia sepium. This comes from the Greek kalu “cup” and stegos “a covering” for the genus name Calystegia and sepium means “of hedges” or “of fences”, because of its climbing tendencies. In addition to wild morning glory, the plant has some fun and interesting common names including old man’s cap, devil’s guts, bride’s gown, white witches’ hat, Rutland beauty, great bindweed and hedge bindweed. It is a member of the Convolvulaceae, the morning glory family.
This plant is easy to grow and becomes aggressive at times, covering other plant to the point of killing them. The vine of the wild morning glory twines around slender stems and objects in a counter-clockwise direction. Darwin described this plant and patiently (I’m guessing) observed that the plant made two revolutions around another stem (size unspecified) every 1 hour and 42 minutes. He even noted that completing the semi-circle moving away from the sun took 14 minutes longer than the semi-circle of growth moving toward the sun!
Wild morning glory vine growing over a shrubby plant. Note the distinctive shape of the leaves. J. Allen photo.
Some identifying characteristics: This herbaceous perennial vine grows up to about 3-10 feet in length and branches freely. It can form tangled masses on structures and other plants or just freely grow along the ground. Stems are reported as being either hairless or with hairs. Young vines may have a red tinge to them. Leaves are shaped like an arrowhead. They, like the stems, may or may not have hairs on both the upper and lower surfaces. The tips are pointed. The leaves are about 2-4” long. The base of the leaf is distinctly angular with lobes described as resembling dog’s ears in shape. Flowers are produced singly and have fused white to light pink petals, forming a funnel shape. Two large green bracts are present on the base of the flower, both in the bud stage and after the flower opens (visible at base of buds in the photo below). Individual flowers are only open for one day. Flowers are present in the northeast from mid-May through September. Two to four seeds are produced in a capsule. The dark brown seeds are shaped like little orange segments and can survive for up to 30 years.
Flower of the wild morning glory, Calystegia sepium.
This plant can be confused with other vines, especially field bindweed (Convolvulus arvensis). Field bindweed has smaller leaves that have a more rounded tip and bases that are rounded or pointed, but not cut off squarely like the ‘dog ears’ of wild morning glory.
While this plant is attractive, it is aggressive enough to be designated a noxious weed in some states. It is not listed as noxious in Connecticut. If you have a problem with the vines and need advice on how to get rid of it, the best method is just hand pulling. This will require persistence because new plants can grow from the rhizomes which tend to be shallow but can reach 10 feet in length. And, as mentioned above, seed can survive for up to 30 years. A study (done in a greenhouse) reported in 1974 that wild morning glory had allelopathic tendencies, meaning that exudates from the roots inhibited the growth of other plants. This would help explain its ability to ‘take over’. Another, more labor intensive tactic that is reported to kill the vines is to unwind them and rewind around the stem or support in the opposite (clockwise) direction.
A number of insects visit the flowers for nectar and act as pollinators. These include long-tongued bees such as bumblebees, little carpenter bees, mallow bee, squash & gourd bee, and the morning glory bee. Day-flying sphinx moths may visit the flowers in the morning. One reference mentions Syrphid flies as well. It is thought that the flowers on the same vine are self infertile. In a study in Japan, it was found that all the pollen was gone by noon. The leaves are eaten by the caterpillar of the common plume moth (Emmelina monodictyla) and by several tortoise beetles. This plant is not favored by mammalian herbivores. The bobwhite and ring-necked pheasant eat the seeds some.
The stalks and shoots are reported to be edible and to have a sweet taste after being washed and steamed. They should not be eaten in large quantities because of a purgative effect. Wild morning glory has been used in traditional medicines as a diuretic. The seeds are toxic in large quantities and the roots are somewhat toxic to pigs but the pigs eat them anyway without having serious trouble.