WOM, Horsetail
 | Author:
Allison Kosto, MSU Broadwater Extension Agent
MSU Broadwater County Extension Agent |
Weed of the Month: Horsetail
\Allison Kosto, MSU Broadwater County Extension Agent
This unique plant goes by many names: horsetail, scouring rush, mare’s tail, snake grass, jointed grass or horse pipes. Horsetail is considered a living fossil and the most ancient plant family alive today. It is the only surviving genus in the horsetail family, a group of plants that flourished during the Devonian period about 350 million years ago. It is mentioned in many historical records including by the Romans as a medicinal plant and during colonial times for scouring dishes and butter churns (hence the name scouring rush). It even was used by cabinet makers for sanding.
Description & Habitat
Horsetail is native to North America. Even though it is a native plant, it has some weedy tendencies that can cause frustration in certain situations. Horsetail is typically found in moist areas such as ditches, fields, meadows, along streams and around ponds. The plant is easy to identify. Horsetail has hollow round stems with ridges. The stems are jointed and easily separate the plant into sections from the joints. Typically, there is a white or black band at each joint. Many times horsetail does not have any branches or leaves. Even if it does have branches, it does not appear to have leaves. However, technically leaves are there even though they look more like scales. Another unique characteristic of horsetail is that it does not flower; instead, it reproduces by spores. It has a rhizomatous root system which means that it can also spread through its root system.
In most situations, there is no concern for horsetail. However, despite its name, horsetail is toxic to horses. It can also be toxic to sheep and cattle, but they have a higher tolerance. However, even horses must eat an excessive amount, more than 20% in hay, to cause death. Usually, animals avoid the plant. There have been a few accounts of horsetail being a nuisance in the garden.
Management
Horsetail is difficult to control due to its reproduction system, extensive roots, stem structure and lack of leaves. Additionally, there has been little research done on the control of this plant. Tillage is not effective and can actually increase the population because of the rhizomatous root system. If you till a field with horsetail, make sure to clean your equipment before going to a new field to avoid transporting rhizomes. Repeated mowing and hoeing can control horsetail, but there is no research on frequency or duration. Similar plants require at least 2 years of repeated disturbance to eliminate. Mulch can be helpful in the garden for control.
Herbicides often suppress rather than control horsetail and are most often effective in combination with another control method. The branched form of horsetail is typically more susceptible to herbicides. Plan for repeated applications of herbicides. Commonly used chemicals include Casoron, Curtail, MCPA, Perspective, Remedy, SedgeHammer and Telar. Always read and follow the entire label when applying herbicide. Horsetail often grows close to water so make sure to read the label to understand any restrictions related to water. Common chemical names are used for clarity but does not imply endorsement of a product or brand.
For assistance on weed identification and management, contact the MSU Extension Office in Broadwater County at 406-266-9242.
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