Menyanthes spp.

Bogbean

Menyanthaceae

Circumboreal: northern Europe, northern Asia, and northern North America

Attracts Pollinators Deer Resistant Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterHigh

HardinessZones 3–7

Overview

Menyanthes spp. is a genus of the family Menyanthaceae represented by the single species Menyanthes trifoliata, known as bogbean or buckbean. It is a hardy aquatic and marginal perennial of bogs, fens, pond edges, and shallow still water across the cooler parts of the Northern Hemisphere. A thick, spongy rhizome creeps along the surface of wet mud or just below water, sending up emergent leaves on long stalks. Each leaf is divided into three smooth, oval leaflets 2-4 inches (5-10 cm) long, resembling those of a broad bean. In late spring, erect flower stalks rise 6-12 inches (15-30 cm) above the water, carrying short racemes of star-shaped flowers about 0.6 inch (15 mm) wide. The five petals are white, flushed pink on the outside, and fringed on their inner surface with dense white hairs. The flowers open from the base of the spike upward over two to three weeks and are visited by bees and hoverflies. The creeping rhizome lets colonies spread across suitable wet ground. Plants need permanently wet, acidic to neutral conditions and decline if the rootstock dries out.

Native Range

Menyanthes trifoliata, the only species in the genus, has a circumboreal distribution, native across northern and central Europe, northern Asia, and northern North America. It grows in bogs, fens, marshes, and the shallow margins of lakes and ponds.

Suggested Uses

Grown at pond and bog-garden margins, in wildlife ponds, and in container water gardens kept permanently wet. The early flowers provide nectar for emerging bees and hoverflies. The genus suits naturalistic wetland and rain-garden plantings on acidic soils.

How to Identify

Identify bogbean by its three-part leaves held above shallow water on long stalks, much like those of a broad bean, arising from a thick creeping rhizome. In late spring the white, pink-backed flowers are marked by an inner fringe of dense white hairs. The wetland habitat and three-lobed emergent leaves separate Menyanthes spp. from other water-margin plants.

Appearance

Size & Dimensions

Height6" - 1'

Width/Spread1'6" - 3'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~3 weeks

Spring Summer

Flowering occurs in late spring and early summer, generally May to June. The star-shaped flowers open in sequence from the bottom of the spike upward over two to three weeks. Bees and hoverflies are the main pollinators of the fringed blooms.

Detailed Descriptions

Foliage Description

Green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-8 hours of direct sunlight daily

• 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 Range5.0 - 7.0(Neutral)

357912

Soil Types

peat loam

Drainagewet

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

2-3 years

Care & Maintenance

Care Guide

Plants grow in full sun to light shade in permanently wet ground, including shallow standing water up to about 4 inches (10 cm) deep over the rhizome. Acidic to neutral, peaty or mucky substrates match the bog and fen habitat of the species. The rhizome must stay wet at all times, and plants fail where water levels fall and the rootstock dries. In ponds, the creeping stems are grown at the margin in baskets or planted directly into saturated soil. Spread is steady, and colonies are thinned by lifting and dividing sections of rhizome in spring. Still or slow-moving water suits the species better than fast flow.

Pruning

Maintenance is limited to removing yellowing leaves and spent flower stalks as they fade. Overgrown colonies are reduced in spring by pulling or cutting away lengths of rhizome. The plant dies back over winter and reshoots from the rhizome in spring.

Pruning Schedule

early spring