Horsetail

Horsetail (Equisetum arvense, field horsetail) is a primitive, non-flowering plant in the genus Equisetum, the only surviving genus of an ancient lineage that dominated forests over 300 million years ago. It reproduces by spores rather than seeds.

It produces two kinds of stems: fertile, brownish spore-bearing stalks in early spring, followed by green, branched sterile stems through summer. Spreading by deep, persistent rhizomes, it is one of the hardest garden weeds to eradicate, but it is also valued historically for scouring.

Identify horsetail by its jointed, hollow stems with whorls of thin branches.

• Green sterile stems with regular joints (nodes) and whorls of slender, needle-like branches, resembling a bottle brush or horse's tail
• Separate pale brown, unbranched fertile stems in early spring, each topped with a cone-like spore structure
• No true flowers or seeds; reproduces by spores
• Rough, silica-rich stems that feel gritty
• Spreads via deep, far-reaching black rhizomes

Horsetail is usually an unwanted, hard-to-remove weed.

• Light: Full sun to partial shade
• Water: Prefers moist to wet soils; common in poorly drained ground
• Soil: Tolerates poor, compacted, sandy or waterlogged soils
• Temperature: Very cold-hardy perennial
• Propagation: By spores and, mainly, by deep creeping rhizomes
• Control: Extremely difficult; rhizomes can reach several feet deep, so digging rarely fully removes it. Persistent removal, improving drainage and repeated treatment over years are needed; small fragments resprout

Field horsetail is native to the Northern Hemisphere and is widespread across North America, Europe and Asia.

It grows in moist, disturbed ground: ditches, roadsides, railway embankments, riverbanks, fields, gardens and damp waste places. It tolerates poor drainage and is often a sign of wet or compacted soil.