Menyanthes trifoliata
Bogbean
Northern hemisphere: Europe, northern Asia, and northern North America
Overview
Menyanthes trifoliata is a rhizomatous aquatic perennial that grows in shallow water and waterlogged ground, spreading by thick, spongy rhizomes that creep across mud or float at the surface. Emergent leaves rise on long sheathing stalks 4-12 inches (10-30 cm) above the water and are divided into three oval leaflets 1.5-3 inches (4-8 cm) long, resembling a broad bean leaf. In spring the rhizome sends up an erect raceme 6-12 inches (15-30 cm) tall carrying 10-20 star-shaped flowers. Each flower is white, flushed pink to reddish on the outside, about 0.6 inch (15 mm) across, with five petals densely fringed with white hairs that give a bearded look. Flowering runs from April to June, followed by rounded capsules. Foliage dies back to the rhizome in autumn and regrows in spring. The plant forms spreading colonies at pond and lake margins and over peaty shallows, and can knit floating rafts of vegetation. It needs permanently wet, acid to neutral conditions and fails in dry ground.
Native Range
Native across the cooler northern hemisphere, including Europe, northern and central Asia, and northern North America. It grows in bogs, fens, marshes, pond and lake margins, ditches, and slow-moving shallow water on acid to neutral peaty soils, from lowland to montane elevations.Suggested Uses
Grown at pond and bog garden margins, in wildlife ponds, and in shallow water features for cover and spring flowers, planted in mud or baskets 12-18 inches (30-45 cm) apart. Suited to permanently wet, acid to neutral sites rather than borders. Flowers draw bees and other insects, and the cover shelters pond wildlife.How to Identify
Appearance
Size & Dimensions
Height6" - 1'
Width/Spread1'6" - 3'
Bloom Information
Flowers from April to June, with peak bloom in May. Each raceme opens its flowers in succession from the base over 2-3 weeks. Colonies in cold or shaded sites flower later and more sparsely than those in open, sunlit shallows.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
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
Care & Maintenance
Care Guide
Grows in full sun to part shade in permanently wet ground or shallow water up to about 12 inches (30 cm) deep, on acid to neutral peaty or mucky soils. It is planted in mud at the margin or in submerged baskets, where the rhizome spreads to form colonies. No feeding is needed in natural water. Spreading rhizomes can fill a small pond margin within a few seasons, so dividing and lifting sections in spring controls its reach. Foliage dies back in autumn. It tolerates cold well but fails if the ground dries out, and few pests or diseases trouble it.Pruning
No pruning is required. Faded flower stems and old leaves are removed as they yellow to keep margins clear. Lifting and dividing the rhizome in spring controls spread and renews crowded colonies.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
springfall
Container Growing
✓ Suitable for container growing
Minimum container size: 3 gallons