Mare's Tail or Horsetail weed (Latin name ‘Equisetum arvense’) is an invasive native herbaceous perennial plant (weed). Mare's Tail is easily recognised throughout the summer and autumn by its upright (5-60cm height) light green, fir tree like shoots (pointed green shoots with folded needle like leaves pointing upward around the stem). These shoots are rough to the touch as they have a natural hard casing. In spring, the plant first appears as light brown stems (20-50cm tall) with a fertile spore producing cone structure at the end of the stems. A single cone can produce 100,000 spores. As a perennial the above ground growth completely dies off in the winter.
Mare's Tail has an underground stem structure called rhizomes. These creeping rhizomes may go down as deep as 2m (7ft) below the surface and spread out laterally. This enables the plant to spread not only by spore dispersal but underground rhizome growth as well. In fact the main method of spread is by vegetative reproduction of detached rhizomes and tubers.
What are the Dangers of Mare's Tail?
Mare's Tail is a pernicious weed capable of rapidly colonising a diverse range of sites as it’s extremely hardy. It spreads quickly, out-competing other plants to form a dense carpet of foliage. Surprisingly due to the relative fragility of the individual stems it also presents a damage risk to hard standing.
Unfortunately it is common to see hard standing (block-paving, macadam roads and pavements) damaged by Mare's Tail growth, where the rhizome has exploited gaps in these surfaces. Developers who have failed to identify and remove Mare's Tail under construction therefore do find this plant re-appearing through newly laid driveways and footpaths!
How to get rid of Mare's Tail
Control can be achieved by professional application of suitable herbicides. However the hard casing of the plant, its deep extensive rhizome system and spore dispersal make it very hard to eradicate. The application of herbicides should be seen as a control measure only in nearly all cases and unlikely to achieve complete eradication.
Complete eradication can be achieved via the digging out (excavation) of the plant, which requires our expertise to ensure that the entire rhizome is identified and removed. This is the preferred method for development sites to reduce the risk of subsequent hard standing damage post construction completion.
Where Mare's Tail has already caused hard standing damage we would only recommend repairing this damage once the Mare's Tail has been dug out (perhaps accompanied by the installation of protective root barrier). If the Mare's Tail was to be treated with herbicide only the risk of re-growth and repeat damage to the hard standing is high.