They don’t get any tougher than Equisetum!!!!
Horsetails are a member of the genus Equisetum, the only genus in the plant family Equisetaceae. Species in the genus Equisetum are commonly considered to be living fossils as they are vestiges of the Carboniferous geological period of 325 million years ago.
Arthur Haines, in Flora Novae Angliae: A Manual for the Identification of Native and Naturalized Higher Vascular Plants of New England, describes eight Equisetum species found in the six New England states. These species occur in a variety of habitats including lawns, landscapes, roadsides, stream banks, lake and pond shores, meadows and riparian forests. Of the species found in New England, landscape and turf professionals most commonly encounter field horsetail, Equisetum arvense.
Equisetum is most closely related to fern. Akin to ferns, they do not produce seed. Horsetails reproduces sexually by spores. These spores are relatively unimportant in the spread of horsetail. The extensive underground rhizome system, commonly reaching depths greater than three feet, are the primary means of reproduction and spread. In the absence of tillage or other forms of soil disturbance, lateral spread of horsetail is relatively slow compared to other weed species that reproduce by vegetative propagules.
Plant description
Field horsetail produces two distinct types of shoots. Produced in the spring, fertile reproductive shoots (photo 1) are 6 to 10 inches tall, are short-lived and do not usually appear in landscape populations. These reproductive shoots are tan to light brown with a spore producing cone at the tip. Sterile vegetative shoots are produced after the fertile shoots. In most cases these shoot are 6 to 8 inches tall and resemble miniature pine trees (photo 2 & 3). Both fertile and sterile stems are grooved and hollow.

Managing field horsetail in landscape areas
Newly installed balled & burlapped nursery stock should be monitored carefully as occasionally horsetail can be introduced via nursery stock. Areas with a population of field horsetail should never be planted to landscape until horsetail is controlled. Proposed landscape areas can be grown as turf for a period of time where attempts to manage horsetail are easier and usually more successful. Although it may take several years, repeated mowing or mechanical removal (hand-pulling) where the dedicated removal of sterile stems depletes the carbohydrate reserves and will eventually exhaust the energy in the rhizome system. Tillage can make the problem worse by spreading the rhizomes and should never be used as part of a management strategy. Growing best in full sun, shading has been known to decrease horsetail vigor.
Landscape herbicides management options
dichlobenil: Barrier Ornamental Landscape Herbicide, Casoron
Formulated as a granular, these preemergence products are applied as a soil treatment. In New England applications are made in early spring after the ground has thawed. Dichlobenil products can be used in landscapes with woody ornamentals only and should not be used where herbaceous landscape ornamentals are present. Conifers may be injured if granules lodge in foliage. Do not apply in sloped areas where runoff and the washing of granules may enter areas such as lawn or areas with herbaceous ornamentals.
halosulfuron-methyl: Sedgehammer, Prosedge 2
Halosulfuron product are used for the postemergence control of horsetail. Applications are to be made as directed sprays and can be applied as over-the-top applications to landscape ornamentals. Applications should be made after horsetail has leafed out and stems are less than 6 inches. Application made when stem height exceeds 6 inches will suppress but not control horsetail. Herbicide symptoms can be observed within 2 weeks after application as a necrotic ring at the base of the plant, while the leaves and stems remain green in color and plant death will follow shortly.
Managing field horsetail in turf areas
Horsetail is usually less of a problem in turf. Horsetail in first noticed in turf where it has spread from existing landscape populations. Horsetail is best management in turf with broadleaf turf herbicides that contain MCPA.
Randy Prostak, UMass Extension Weed Specialist