Equisetum arvensis

Scientific Name	Equisetum arvensis L.
Common Names	English: Field horsetail; German: Acker-Schachtelhalm; Spanish: Cola de caballo; French: Prêle des champs
Description	Perennial with a spreading rhizome system that produces numerous shoots and tubers, mainly occurs in moderate areas.

Characteristic Features

Upright, hollow, jointed, cylindrical stems with inconsequential and easily overlooked leaves.

Stems

Two types of stems: The fertile (reproductive) stems appear in the early spring and are whitish to light brown, unbranched, hollow, 8 mm (0.31 inch) in diameter, cylindrical, leafless, jointed, and 15-30 cm (5.9 - 11.8 inch) long with 8 to 12 teeth.
Sterile stems are green, erect or somewhat prostrate, 15-60 cm (5.9 - 23.62 inch) tall and are composed of slender, grooved, hollow joints, 1 to 1.5 mm (0.039 - 0.059 inch) in diameter .The middle and upper joints have 6 to 12 needle-like branches that are 5-10 cm (1.97 - 3.93 inch) long, jointed but not hollow, 3- or 4-angled with blackened tips. The stems and branches are surrounded by a small, toothed sheath at each node.

Leaves

Leaf sheaths of fertile shoots with ridged, rough textured 8 - 12 dirty brown teeth. Leaf sheaths of sterile shoots triangular-lanceolate, half as long as sheath tube.

Flowers

No flowers.

Fruit

Pinecone-like structure formed at the end of the fertile stem produces thousands of minute, pale green to yellowish spores.

Seeds

Fertile stems emerge in mid-April, begin spore production in early May, and die soon after. Sterile stems emerge in late spring as the fertile stems wither, and persist until frost.

Viability of Seeds

Small tubers produced along the rhizomes are capable of surviving long periods in the soil.

Propagation

Reproduces by spores but mainly by horizontal rhizomes and tubers.

Habitat

Wet, poorly drained areas of fields and grasslands; wet meadows; streams, well drained sites in farm fields, orchards and nursery crops, roadsides, railroad tracks and beaches.

Soil

Sandy or gravelly soil, acidic and wet soil conditions, soils with high available potassium levels.

Agricultural Importance

Rhizome fragments and tubers are easily spread to new areas in infested soil. As a result, this species is often difficult to control. It can be a strong competitor with crops, as well as a threat to grazing animals due to toxic compounds. Field horsetail extracts can inhibit germination and reduce vigor of 30 grass species.

Useful non-chemical contribution to Integrated Weed Management

Minimum or zero tillage, avoid soil compaction and soil acidity.