Calystegia sepium

Native

Wet. Meadows, prairies, thickets, forest edges, stream banks, river banks, ditches. Disturbed sites. Full to partial sun.

June to September

White to pink

Trailing, 1½′ to 10′ long

This is a perennial vine that rises on multiple stems from a deep, creeping rhizome and a deep, fibrous root system. The rhizome is branched and can be over 10′ long.

The stems are light green or red, finely hairy or hairless, freely branched, and either angled or round. They are usually awkwardly climbing over adjacent vegetation or structures (scrambling), occasionally prostrate on the ground but not rooting at the tip (trailing). The stem grows in a spiral, at least toward the tip, curving around nearby plants (twining), allowing the stem to climb. They are usually 1½′ to 10′ long but can reach up to 13′ or more.

The leaves are alternate, 2″ to 4″ long, and 2¾″ to 3″ wide. They are on leaf stalks that are always more than, usually much more than, half as long as the midvein of the attached leaf. The leaf blade is triangular in outline, arrow-shaped, pointed at the tip, and indented at the base. The basal lobes are trapezoidal and may be directed either outward or downward. The upper and lower surfaces may be hairless or have short hairs. The margins are untoothed.

The inflorescence is usually solitary, occasionally paired flowers rising from the leaf axils above the midpoint of the stem.

The flowers are large, conspicuous, funnel-shaped, and 1½″ to 2¾″ long and wide. They are on 2″ to 6″ long flower stalks. There are two large, leaf-like bracts at the base of the flower. The bracts are ½″ to 1″ long and usually cover the sepals (calyx). Within the bracts are 5 green, elliptic to narrowly egg-shaped, 7 ⁄16″ to ⅝″ long sepals. There are 5 white to pink petals fused into a funnel-shaped tube. The outer margin of the corolla is very shallowly lobed. The flowers open in the morning and close at night, but often remain open on moonlit nights. They are not fragrant. Insects may be attracted to the warmth inside the funnel, which may be 5° above the air temperature.

The fruit is an egg-shaped, ⅜″ to ⅝″ long capsule with 2 to 4 seeds.

Black bindweed (Fallopia convolvulus) is a shorter vine, no more than 40″ in length. The stems and leaves do not have a milky latex. The leaf stalk has an ocrea at the base. The flower is small, ⅛″ to 3 ⁄16″ long, and not showy. The fruit is an achene.

Common morning-glory (Ipomoea purpurea) has rounded, heart-shaped, not triangular, arrow-shaped, leaves. The basal lobes of the leaf blade are broadly rounded, not squared off or pointed. The flower is blue to purple.

Field bindweed (Convolvulus arvensis) is a smaller plant. The leaves are smaller, 1″ to 2″ in length. The basal lobes of the leaf blade are pointed, not trapeziodal. The bracts are much smaller and are positioned on the stem well below the inflorescence. The flowers are smaller, 1″ or less long and wide.

Ivy-leaved morning-glory (Ipomoea hederacea) has 3-lobed leaves. The flower is blue to purple.

Low bindweed (Calystegia spithamaea) stem is erect, does not twine, and does not get over 20″ long.

Sources: 2, 3, 5, 7.

Subspecies
Seven subspecies are recognized, two of which occur in Minnesota (see Subordinate Taxa below). However, no information about the morphological differences between these two subspecies is available.