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Detailed information sheet

Click on the photos for a larger image.

Botanical name :
Equisetum arvense
Family :
Equisetaceae (horsetail) family 
Common name :
field horsetail 
Also known as :
common horsetail, scouring rush  
Where is it originally
from? :
Temperate northern hemisphere
What does it look like? :
Erect, colony-forming, summer-green perennial, primitive fern-ally to 10-80 cm with extensive, deep, freely branching rhizomes with round tubers. All aerial parts die back in winter. Stems are of two types: (1) sterile stems (10-80 x 1-5 mm diameter) are green, jointed, hollow, ribbed or grooved, very rough to touch (containing silica), with lateral branches in whorls and leaves (10mm) which are green sheaths. Resembles a pine seedling, and (2) fertile stems are pale brown, shorter with larger joints, unbranched, with pale brown 14 mm sheaths, appear in early spring before sterile stems, produce conspicuous (4-40 mm long) terminal cones, and die quickly after shedding spores. Spores are seldom produced in New Zealand. 
Are there any similar
species? :
Rough horsetail (Equisetum hyemale) is very similar but rare, it has slender, taller, very rough, asparagus-like spears with black rings, no leaves, no (or very occasionally few small) branches, cones on green stems. E. fluviatile (rare). 
Why is it weedy? :
Matures and spreads quickly, forming dense, long-lived mats. Tolerates flooding to dampish-dry soil, warm to very cold, wind, and deep burial but is intolerant of dry soils. Toxic to stock. 
How does it spread? :
Rhizomes and tubers are spread by water, soil and river gravel movement and contaminated machinery. Sources include rivers, roadsides, pasture, and gardens, where it has been found being grown as a homeopathic remedy. 
What damage does it do? :
Forms pure stands in wide range of damp habitats, preventing the seedlings of native species from establishing. Blocks and alters watercourses, causing flooding. 
Which habitats is
it likely to invade? :
Bare land, river systems especially silty, sandy and gravelly sites, and streambanks.
What can I do to get
rid of it? :
Report all sites to your regional council or local Department of Conservation office.
1. Dig out and incinerate all parts and contaminated soil. 
2. Spray (summer): metsulfuron-methyl 600g/kg (5g/10L) or Tordon Brushkiller (25ml/10L). Add penetrant. 
What can I do to
stop it coming back? :
Resprouts constantly from rhizomes and tubers. Resistant to most herbicides, extremely difficult to kill. Lowering watertable can slow rate of spread. 

Description:field horsetail.Photo:by T.James


For more detailed botanical descriptions of weed species, check out the Plant Conservation Network's website at http://www.nzpcn.org.nz/exotic_plant_life_and_weeds/index.asp

Click here for Herbicides and Trade names

*The chemical control methods in this manual were devised by Department of Conservation staff for Department of Conservation operations and should not be used as a substitute for the pesticide manufacturer's label instructions. The Department of Conservation takes no responsibility for any liability or damage to any person, property or thing which may occur as a result of the use of any pesticide in accordance with the chemical control methods contained on this website.


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