Overview
Equisetum fluviatile is a horsetail, a spore-bearing relative of ferns, that grows in shallow water and waterlogged ground. Its erect, jointed, bright green stems rise 12-60 inches (30-150 cm) and are smooth, with a very large central hollow that takes up most of the stem width, leaving only a thin wall. At each joint sits a sheath of small dark teeth, the reduced leaves, and many stems carry whorls of slender branches, though some plants stay almost unbranched. The plant has no flowers; instead, blunt, cone-like structures at the stem tips release spores in spring. It spreads strongly through deep, far-reaching rhizomes, forming dense stands at the margins and in the shallow water of ponds, lakes, canals, ditches, fens, and marshes. The hollow stems are weak and often lean or break in exposed sites. It grows on a wide range of wet soils and can dominate open shallow water, crowding out other marginal plants. Like other horsetails it contains thiaminase and silica, which make it toxic to horses and other livestock that graze it, whether fresh or in hay. The stems die down in autumn and regrow from the rhizomes in spring.
Native Range
Native across the cool temperate and boreal Northern Hemisphere, including Europe, northern Asia, and North America. In North America it is widespread across Canada and the northern United States.Suggested Uses
Grown at pond and lake margins and in wildlife and bog gardens as a vertical marginal plant for shallow water. It suits naturalistic water features where its spread can be contained. Its aggressive rhizomes and toxicity to livestock make it unsuited to small ponds, mixed margins, or sites near grazing.How to Identify
Appearance
Size & Dimensions
Height1' - 5'
Width/Spread1' - 3'
Reaches mature size in approximately 2 years
Bloom Information
As a horsetail it does not flower. Cone-like spore heads form at the tips of green stems in spring, ripening and shedding spores over a few weeks. Most spread, however, is vegetative, through its extensive creeping rhizomes.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-10 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
Equisetum fluviatile grows in full sun to light shade in shallow standing water or permanently wet, mucky soil, tolerating a wide pH range of about 5.0-7.5. It is suited only to ponds, bog gardens, and marginal water of at least a few inches depth, and dies out on dry ground. It spreads fast and far by deep rhizomes, so in gardens it is usually confined to a lined pond or a sturdy submerged container. It is hardy across USDA zones 3-8 and dies down each winter. It needs no feeding in mineral wet soil. Its toxicity to grazing animals limits its use near pasture.Pruning
No pruning is needed. Stems can be cut or pulled to limit spread, though the rhizomes regrow readily. Clearing the spring cones before they ripen reduces spread by spore.Container Growing
✓ Suitable for container growing