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Portrait of Great horsetail

Nature · Ferns, grasses & other plants

Great horsetail

Native · sterile shoots 30–150 cm, rarely over 2 m · springs and seepages on clay

Equisetum telmateia — Equisetaceae

Great horsetail is the giant of the British horsetails, a plant of springs and wet clay banks whose ivory-white, densely branched stems look like fleshy bottle-brushes. In April and May it sends up pale, unbranched cone-bearing shoots that wither within a couple of weeks, before the branched green shoots take over. It belongs to a lineage older than the dinosaurs, though its fossil cousins were far taller.

How to spot them

  • ▸Very stout, ivory-white or pale stems in whorls of many fine green branches, up to 1.5 m or more
  • ▸Fertile, pinkish-buff unbranched shoots with a fat cone in April and May, appearing before the green ones
  • ▸Sheath teeth dark brown, long and pointed, on brittle, easily snapped stems
  • ▸Wet, base-rich clay or peat where springs and seepages emerge: cliff bases, ditches and riverbanks
  • ▸Look-alike: field horsetail is smaller, greener and more spreading, and lacks the ivory-white stem; this species is described as 'completely unmistakable'

How to know it

The tallest of its group outside the tropics, with ivory-white stems whorled with fine green branches

Great horsetail — sometimes over 2 m.

Fertile shoots appear in April and May, before the green shoots, and wither within about two weeks

Great horsetail — cone-like spikes on pale unbranched stems.

Forms dense colonies where springs seep out of base-rich clay, on cliff bases and wet roadside banks

Great horsetail.

Its brittle, fleshy stems are easily broken by trampling

Great horsetail.

This species shares its wet ground with marsh horsetail but is far taller and whiter

Great horsetail — Equisetum telmateia.

Quick-fire facts

  • •The tallest horsetail of the temperate world: sterile stems typically 30–150 cm, rarely reaching 240 cm
  • •Typically grows on poorly drained clay or shallow peat flushed by base-rich, often calcareous, groundwater
  • •Fertile stems emerge in April–May and die off within about two weeks; the green sterile stems then follow
  • •Rarely found above about 250 m in Britain, according to the BSBI county account
  • •Horsetails are ancient: the Equisetum lineage goes back to the Carboniferous, when relatives such as the calamites grew as trees
  • •A spore plant, not a flowering plant; its cones release spores with tiny elaters that unfurl to help dispersal
  • •Commonly associated with marsh horsetail and occasionally water or rough horsetail in the same wet ground

Drill it — 5 cards

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Sources