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Hippuris vulgaris

common Mare's tail

Plantaginaceae

Circumboreal: Europe, northern Asia, and North America

Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterHigh

HardinessZones 3–10

Overview

Hippuris vulgaris, common mare-tail, is an aquatic perennial in the family Plantaginaceae that roots in mud and sends erect, unbranched green shoots above the water surface. The emergent stems stand 4-24 inches (10-60 cm) tall and bear regular whorls of 6 to 12 narrow, linear leaves 0.4-1.5 inches (1-4 cm) long, giving a bottle-brush profile. Submerged shoots earlier in the season carry longer, limp, paler leaves. It spreads by creeping rhizomes in soft sediment to form dense stands in shallow still or slow water and on wet mud at the margins of ponds, lakes, ditches, and slow rivers. The flowers are minute and petal-less, sitting singly in the leaf axils of the emergent stems in summer, and are wind-pollinated. Despite the name and look, it is unrelated to the spore-bearing horsetails (Equisetum spp.). It dies back to the rhizome in winter and reshoots in spring. One limitation is its vigorous spread, which can crowd small ponds and shallow margins.

Native Range

Hippuris vulgaris has a wide circumboreal range across Europe, northern and central Asia, and North America, growing in shallow fresh to slightly brackish water and on wet mud. It ranges from lowland ponds to mountain and arctic pools.

Suggested Uses

Grown as a marginal and shallow-water plant in wildlife ponds, pool edges, and bog gardens, set in mud or planting baskets in up to 24 inches (60 cm) of water. The upright stems give vertical structure and shelter for pond insects and amphibians.

How to Identify

Mare-tail is known by its erect, unbranched green stems standing above shallow water, ringed with regular whorls of 6 to 12 narrow linear leaves like a bottle-brush. The tiny flowers are petal-less and hidden in the leaf axils. It roots in mud and forms colonies in still or slow water. Its soft, fleshy stems and aquatic habit separate it from the tougher, spore-bearing horsetails (Equisetum spp.), which have hollow jointed stems and no true leaves.

Appearance

Size & Dimensions

Height4" - 2'

Width/Spread1' - 3'

Reaches mature size in approximately 2 years

Colors

Flower Colors

green

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~10 weeks

Summer

Tiny petal-less flowers open in the leaf axils of the emergent stems from June to August. They have no conspicuous parts and are wind-pollinated, so they pass almost unseen. Small one-seeded nut-like fruits ripen later in summer, though spread is mostly by rhizome.

Detailed Descriptions

Flower Description

greenish, inconspicuous

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-12 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 Range6.0 - 8.0(Neutral)

357912

Soil Types

loam clay

Drainagewet

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

1-2 years

Care & Maintenance

Care Guide

Hippuris vulgaris grows in full sun in shallow still or slow fresh water up to about 24 inches (60 cm) deep, rooted in fertile mud or loam. It is hardy across a wide climate range, roughly USDA zones 3 to 10, and dies back to the rhizome each winter. It spreads quickly by rhizome and can fill small ponds, so it is often grown in planting baskets to limit its reach. It needs no feeding when rooted in fertile pond sediment. Plants are increased by dividing rooted rhizome sections in spring. It has few pests of concern in pond settings.

Pruning

Excess stems and rhizome are thinned in spring or summer to keep open water and limit spread. Faded top growth is cut down or left to die back over winter. Sections of rhizome left in mud regrow, so removal is repeated as needed.