Introduction

Equisetum arvense is a member of a very primitive family of plants. It has been unchanged for millions of years except for the size – the Prehistoric form could attain up to 30 metres.

It exists in about 20 different species mostly located in the Northern Hemisphere. In the UK, it is considered as a weed pest and it is becoming increasingly prevalent and damaging.

Nevertheless, this plant contains a large number of chemicals that can be useful in medicine

Description

Horsetail is a dimorphic, rhizomatous perennial plant. It is a unique plant with two distinctive types of stems. One variety of stem grows early in spring; it is brown-coloured and has spore-containing cones on top.

The mature form of the plant appears in summer and has branched, thin, green, sterile stems. Vegetative stems, which can attain a height of up to 90 centimetres, persist until the frost period and then die. During winter, horsetail can only survive through a system of rhizomes and tubers.

Its system of rhizomes penetrates soil to a depth of 2 metres vertically and has many horizontal branches which can reach 1.5 metre. These rhizomes bear tubers. The reproduction of the plant is made by the extension or the fragmentation of this rhizome system from which tubers or spores are detached. For instance, 10 centimetres length of rhizome is able to produce 64 metres of new rhizome within one year. As with many invasive plants, Horsetail can regenerate from the smallest rhizome node.

Impacts

Horsetail grows in a large number of places and can be found in orchards and landscaped areas such as marshes and sand dunes.

But like Japanese Knotweed, it also appears in newly built areas, pushing through tarmac and paving-stoned environments.

Moreover, it can thrive in all type of soils and it even prefers poor drainage, acid conditions and soil compaction which encourages tuber production.

Control Methods

It is extremely resistant to eradication as the rhizomes are very hard to completely remove and the small, waxy leaves repel herbicides. As the roots of Horsetail go very deep into the soil, it is rarely possible to remove the plant by excavation.

Cutting stem and re-growth can lead to a substantial stem density reduction but it requires 3 or 4 seasons.

Horsetail is unaffected by many herbicides but using Dichlobenil granules can prove successful in early spring before growth starts or Glyphosate in late summer.

Horsetail requires plenty of light and applying a black sheet on it can also be a good means to control it.

 

Resources:

Case Studies

Capability Statement

LK Group Brochure

Images: