Horsetail (Mares Tail)
Perennial & invasive weed
Horsetail, also known as mares tail, is an ancient, deep-rooted perennial that is notorious in compacted or poorly drained ground. It can invade beds, paths and vegetable plots from beyond the garden boundary. Total eradication is very difficult, but regular weakening of the top growth, improved conditions and long-term persistence can greatly reduce its vigour.
How to identify it
In spring, fertile shoots appear as pale brown, hollow, jointed stems, commonly 10-30 cm high, with a cone-like spore head at the tip. Later, green sterile shoots reach about 20-60 cm and carry whorls of fine side branches, giving a feathery miniature-fir appearance. Stems pull apart at the joints. The plant spreads mainly through tough, black rhizomes that can run deeply below the surface, well beyond ordinary digging depth.
Where it grows
Horsetail is most frequent in damp, compacted, acidic or poorly drained soil, though it survives in many garden conditions. It appears from spring, with green growth most obvious through summer. In UK gardens it often emerges in borders, lawns, vegetable patches, cracks beside paths and ground recently disturbed by building or cultivation, sometimes arriving from neighbouring land.
Why it is a problem
Deep rhizomes store enough energy to produce repeated shoots after shallow removal. Their spread beneath beds makes the plant hard to contain, while dense stems compete with crops and spoil tidy planting. Rotavating or casually digging can cut rhizomes into pieces that produce more shoots. A well-established colony may need several years of steady control.
How to control it
Never rotavate horsetail. Pull or hoe the green shoots whenever they appear, preferably before they become tall, to gradually exhaust the rhizomes. Fork out accessible roots carefully, removing every black fragment you can find, but avoid chopping them up. Improve drainage and reduce compaction where practical. Use a thick mulch or securely weighted light-excluding cover on clear ground, lifting edges to remove shoots. Repeat this work for years; total eradication is often unrealistic.
Commonly confused with
Young green shoots can be confused with asparagus foliage, but horsetail has distinctly hollow, jointed stems and whorled branches. Its brown fertile shoots may resemble small mushrooms at a glance, yet the terminal spore cone is distinctive. Do not confuse it with mare's-tail, an aquatic plant sometimes sold for ponds.
Horsetail (Mares Tail): frequently asked questions
How do I identify horsetail (mares tail)?
In spring, fertile shoots appear as pale brown, hollow, jointed stems, commonly 10-30 cm high, with a cone-like spore head at the tip.
How do I get rid of horsetail (mares tail)?
Never rotavate horsetail.
Where does horsetail (mares tail) grow?
Horsetail is most frequent in damp, compacted, acidic or poorly drained soil, though it survives in many garden conditions.
General guidance for UK gardens and allotments, focused on prevention and non-chemical control. For a confirmed identification, the RHS or a local garden centre can help. Page updated 19 Sep 2026.