Rough horsetail is considered a pest plant because it spreads aggressively through its deep, extensive rhizome system and spores, making it very hard to control or eradicate. It thrives in a wide range of soil types and conditions, often outcompeting crops and desirable vegetation. It can threaten biodiversity of wetlands and waterway edges. Additionally, its resilience to many herbicides and its ability to regrow from even small root fragments make it persistent and costly to control. 

• Size: Can grow up to 1.2 metres high. 
• Leaves: There are no leaves, but reed stems, which can create large stands.  The stems are hollow and have coloured ribbed bands.  
• Flowers: It does not produce flowers. Instead, spores are concentrated at the tip of the stem on an asparagus-like head. 
• Root system: Rhizomes can grow to 1 metre deep. 
• Habitat: Includes forest margins, riparian margins (land that runs alongside a waterway, such as a river, stream, lake or wetland) and ponds.

Rough horsetail grows throughout the year, and each new stem can grow to full height in a few weeks. 

Rough horsetail is declared an unwanted organism in the National Pest Plant Accord (NPPA). Any species declared a pest under the NPPA cannot be sold or be in a place where plants are being sold. 

Pest plants cannot be propagated, bred, multiplied, communicated, released, caused to be released, or otherwise spread. 

www.orc.govt.nz/roughhorsetail