Horsetail

Also known as:
Snake Grass
Family:
Equisetaceae
Origin:
Temperate northern hemisphere.

General description

Evergreen perennial fern allies <1m high. Rush-like stems ridged (very rough to the touch), cylindrical with black joints. Conspicuous spore-bearing cone-like heads at stem tips in spring. Extensive rhizomes. Some parts of plant above ground die back in winter.

Wet riverbanks, lake edges, moist fields. Tolerates cold, flooding, deep burial.

Spores (seldom in NZ) dispersed by wind & water. Spread by extensive rhizomes, moved in soil, gravel, on machinery.

Form pure stands in wide range of damp habitats. Prevent regeneration of other species. Block waterways, causes flooding, siltation etc. Toxic.

Site management

Resistant to most herbicides. Extensive rhizomes make control difficult. Lowering watertable slows rate of spread.

Recommended approaches

1. Weedmat over a long period.
2. Dig out small plants & incinerate.
3. Spray in summer (5g metsulfuron+10ml penetrant/10L or 60ml Tordon BK +10ml penetrant/10L).
4. Apply residual herbicides (e.g. Hexazinone, dichlobenil). Follow up whenever sprouts appear until eradicated (2-3 times annually).

Caution: when using any herbicide or pesticide PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.

RPMS status

Surveillance - Whole Region
National Pest Plant Accord species - nationwide
horsetail - Main species image