Japanese Bindweed (Calystegia hederacea)
Morningglory Family (Convolvulaceae)
Colvolvulus japonicus, Convolvulus pellitus, California rose, Japanese false bindweed.
Origin and Distribution:
A native of eastern China, Japanese bindweed was likely brought to North America as an ornamental or it is possible that it entered as a contaminant of nursery plants. The weedy form found growing in the U.S. is from a cultivated variety in which the number of flower petals was doubled. There are reports of finding this weedy escape in 12 of 88 counties in Ohio. It is often found along roadsides and railroad right-of-ways.
Japanese bindweed is a creeping perennial. Its appearance is similar to that of hedge bindweed except it has smaller flowers and the bracts enclosing the base of each flower are smaller. The weedy form that escaped cultivation has a distinctive double flower. Compared with other bindweed flowers, this is a unique flower in that it has twice the number of petals and looks similar to a rose or carnation. No plants studied so far have produced seeds, so it is assumed that reproduction is vegetative by way of spreading roots.
Roots are perennial and spreading.
Seedlings and Shoots:
Stems are usually hairless.
Leaves are alternate, triangle-shaped, and hairless. At the base of each leaf are 2 lobes, one on either side of the leaf stalk (petiole).
Most naturalized individuals have double the number of petals so they appear to have a flower inside of a flower. Flowers are funnel-shaped, pink, and 1 to 2 inches long. Attached to the stalk and enclosing the base of each flower are 2, small, leaf-like bracts.
There is no evidence of seed formation in field- or greenhouse-grown plants. It is possible that other conditions may produce seed-bearing plants; however, the primary means of reproduction seems to be vegetative by way of spreading roots. It was determined that Japanese bindweed found infesting a potato field in Ohio likely arose from roots contaminating the tubers.
There is little information about this plant. However, other morningglory species are not poisonous to humans, although their seeds can be dangerous if consumed in large quantities.
Facts and Folklore:
The flowers of Japanese bindweed are short-lived, with some lasting for a single day.
Compared with hedge bindweed, which is a close relative, Japanese bindweed emerges later and its growth rate is slower.