Family: Morningglory Family (Convolvulaceae)
Origin and Distribution: Bigroot morningglory is native to North America. Its current distribution is primarily throughout the eastern half of the U.S. In Ohio, bigroot morningglory is found in the southern 2/3 of the state. The plant is commonly found in cultivated fields, old fields, fencerows, waste places, along roadsides, and in other disturbed areas. It prefers to grow in dry sandy soils.
Plant Description: Bigroot morningglory is a perennial that shares numerous characteristics with other morningglories including twining vines, funnel-shaped flowers, and heart-shaped leaves. Unlike its relatives, bigroot morningglory has a very large and deep taproot. Reproduction is by seeds and creeping roots.
- Root system - The root system consists of a large, deep taproot and thick, yellowish-white creeping roots. The tuber-like taproot can measure 7 feet long and 4 or more inches in diameter.
- Seedlings & Shoots - The first seedling leaves (cotyledons) are oval and emerge on long leaf stalks (petioles), with the point of attachment to the root remaining below ground.
- Stems - Stems are purplish, usually hairless, and not often branched. The trailing or climbing stems emerge vertically from the ground for 1 to 2 feet and then extend horizontally across the soil surface. They grow up to 10 feet long. More than one shoot emerges from each root.
- Leaves - Leaves are alternate, 2 to 6 inches long, and heart-shaped. The sides frequently contract giving the leaf a fiddle-like shape. Leaves attach to stems by way of long petioles. Leaves can be either hairy or hairless but petioles are usually hairless.
- Flowers - Flowers are alternate, funnel-shaped, 2 to 3 inches across, and white with pinkish-purple stripes radiating from the center. Flowers form either in few- or several-flowered clusters at the end of stalks arising from the stem at the leaf axils. Flower stalks exude a milky sap if broken or crushed.
- Fruits & Seeds - Fruits are egg-shaped capsules containing 2 to 6 seeds. Seeds are red-brown, flattened, oval, and covered with soft white hairs making them appear fringed.
Similar Species: Leaves and flowers of bigroot morningglory resemble those of annual morningglory species (Ipomoea spp.). However, annual morningglories have a small taproot, while bigroot morningglory has a large perennial taproot. Also, annual species are generally hairier than bigroot morningglory. Leaves may resemble honeyvine milkweed (Ampelamus albidus) leaves; however, honeyvine milkweed flowers are small and not funnel-shaped.
Biology: Growing without crop competition, bigroot morningglory can produce 3000 seeds per plant. Roots send up new shoots in mid-May to early June but seeds germinate throughout the growing season. Flowering begins in mid-July for first-year plants, mid-June for older plants, and continues until the frost. Control is difficult because bigroot morningglory emerges late, has a large taproot that extends well below the plow line, and can reproduce from root cuttings. Post emergence herbicides generally provide good control.
Toxicity: There are no references indicating that this plant is poisonous; however, seeds of many morningglorys have been reported to be toxic to livestock and humans if consumed in large quantities.
Facts and Folklore:
- 'Morning-glory' was commonly used as a name for the plant because flowers open at night or in diffuse light.
- The large fleshy root of bigroot morningglory, which is closely related to cultivated sweet potato, can weigh over 66 pounds.