Amphicarpaea spp.

hog peanut

Fabaceae

Eastern North America, East Asia, and parts of Africa

Attracts Pollinators Attracts Butterflies

Native to North America

SunPart Shade – Full Shade

WaterMedium

Overview

Amphicarpaea spp. is a genus of about three species of twining annual and short-lived perennial legumes in the family Fabaceae, native to eastern North America, East Asia, and tropical Africa. Plants produce slender climbing stems 1-5 ft (0.3-1.5 m) long that twine over surrounding vegetation, bearing alternate trifoliate leaves with broadly ovate leaflets 0.8-3 in (2-8 cm) long. The genus is amphicarpic, producing two kinds of flowers. Aerial flowers are pea-shaped, pale purple to white, 0.3-0.6 in (8-15 mm) long, and borne in small clusters from the upper leaf axils in summer. Separate self-pollinating flowers form at or below ground level and develop fleshy single-seeded pods just under the soil surface, the structures that give the North American A. bracteata its common name hog peanut. Aerial pods are flat, curved, and contain three to four seeds. Stems and leaves die back at the end of the growing season. The genus fixes atmospheric nitrogen through root nodules and grows in moist woodland, thickets, and stream margins. Dense twining growth can smother low herbaceous plants.

Native Range

Amphicarpaea spp. is native to eastern North America, East Asia, and parts of tropical and southern Africa. The most widespread species, A. bracteata, ranges across eastern Canada and the eastern United States.

Suggested Uses

Amphicarpaea spp. is grown in woodland and native-plant plantings, naturalised shade gardens, and habitat restoration. The underground seeds are eaten by small mammals and ground-feeding birds, and the foliage serves as larval food for some sulphur butterflies.

How to Identify

Recognise Amphicarpaea spp. by its slender twining stems and alternate trifoliate leaves with ovate leaflets 0.8-3 in (2-8 cm) long. In summer, small clusters of pale purple to white pea flowers 0.3-0.6 in (8-15 mm) hang from the upper leaf axils, while inconspicuous self-pollinating flowers occur near the stem base. The single-seeded pods set near or below the soil surface separate the genus from other twining legumes.

Appearance

Size & Dimensions

Height1' - 5'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

Summer Fall

Aerial pea-shaped flowers open from midsummer into early autumn (roughly July-September in the Northern Hemisphere), pale purple to white and clustered in the upper leaf axils. Self-pollinating basal flowers form over the same period and mature into underground pods. Flowering ends as the foliage dies back with the first frosts.

Detailed Descriptions

Flower Description

pale purple to white

Foliage Description

green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.0(Neutral)

357912

Soil Types

loam

Drainagemoist

Water & Climate

Water Needs

Medium

Care & Maintenance

Care Guide

Across the genus, Amphicarpaea spp. grows in moist, humus-rich soils in partial shade at woodland edges, in thickets, and along stream banks. Plants tolerate full shade but flower more sparsely in deep shade, and they need consistent soil moisture through the growing season. Because the stems twine, plants climb over neighbouring vegetation or low supports rather than self-supporting. Root nodules fix nitrogen, so supplemental feeding is seldom needed. Self-seeding from both aerial and underground pods can produce dense stands in suitable damp ground. In cultivation the genus is grown mainly in native-plant and woodland-restoration settings.

Pruning

Routine pruning is not required for these herbaceous twiners. Where spread onto adjacent plants is unwanted, stems can be cut back or pulled during the growing season, and the annual dieback clears the previous seasons growth.