Horsetail, field (Equisetum arvense)

Horsetail, field description

Distinguished by its ashy-gray, unbranched, leafless shoots tipped with brownish, spore-producing cones in early spring, and later, from late spring or early summer onwards, by its whorls of 6 to 8 green, leafless branches and complete absence of flowers.

Field horsetail is poisonous when consumed in large quantities. Horses, especially young ones are most affected. Hay containing horsetail is particularly dangerous.

Propagation

Perennial, spreading by horizontal, creeping rootstocks and spores.

Distribution

Field horsetail occurs in all parts of Canada in low lying areas with poorly drained soils, as well as in sandy or gravel soils with good drainage.

Identifying Horsetail, field

Seedling

Reproduction by spores produces unbranched stems with cone-like structures at the tip. The cones contain spores. These stems appear in early spring, lasting for several weeks, then wither, making way for sterile, green, branched stems.

Mature plant

Stems are erect, branched with wire-like branches, 8 to 12 inches high. Branches hollow, tough, jointed, in whorls around the main stem.

Leaves are small cup-shaped, toothed, sheaths at the joints on the stems.

Root structure description

Horizontal , creeping, roots send out new shoots each year.

Flowers

Because horsetail does not have flowers, it does not have seed. Spore bearing stems appear for a short time in early spring. The green, branched stems emerge from creeping roots in May and last until fall freeze-up.