Equisetum hyemale, commonly called Scouring Rush or Rough Horsetail, is a non-flowering, rush-like, rhizomatous, evergreen perennial which typically grows 3-5 feet tall and is native to large portions of Eurasia, Canada and the U.S. It typically occurs in wet woods, moist hillsides and peripheries of water bodies (lakes, rivers, ponds). This species features rigid, rough, hollow, vertically-ridged, jointed-and-segmented, bamboo-like, dark green stems (to 1/2” diameter at the base) which rise up from the plant rhizomes. Each stem node (joint) is effectively marked by a whorl of tiny, stem-clasping, scale-like leaves which are fused into an ash-gray sheath (1/4” long) ending in a fringe of teeth. Teeth are usually shed during the growing season. Each sheath is set off and accentuated, both above and below, by thin, stem-ringing, black bands. Photosynthesis is essentially carried on by the stems of this plant. Vegetative and fertile stems are alike in this species, with some vegetative stems bearing, at the stem tips, pine cone-like fruiting heads (to 1” long) (strobili) which contain numerous spores. The evergreen stems are particularly noticeable in winter and can provide significant interest to the landscape. Stems have a high silica content and were used by early Americans for polishing pots and pans, hence the common name of Scouring Rush. Equisetum is not a rush however. Nor is it a fern. Equisetum is the single surviving genus of a class of primitive vascular plants that dates back to the mid-Devonian period (350 + million years ago). Today, the equisetums are categorized as fern allies in large part because they, like the ferns, are non-flowering, seedless plants which reproduce by spores.
It is best grown in medium to wet soils in full sun to part shade. It tolerates an extremely wide range of soils, however, and will grow in up to 4” of standing water. It spreads to form large colonies in the wild. Homeowners are often more interested in learning how to remove this plant than how to grow it. It can be aggressive and if not preemptively restrained, it can spread by branched, creeping rhizomes. Once established, its rhizomes spread wide and deep. Consider using soil barriers to restrict growth. In water gardens or tub gardens, plant in pots at water bottom to contain growth (both height and spread).
In the right spot, this can be a very interesting plant. It makes a very interesting landscape statement when confined to narrow plantings along walls, or in large containers.The genus name comes from the Latin words equus meaning a horse and seta meaning a bristle and the specific epithet means of winter or flowering in winter. Most probably for its winter interest as Equisetum is not a flowering plant.
There are no serious insect or disease problems, although in the right conditions, it is an aggressive spreader.
It is adaptable to water gardens. Japanese gardens. Bog gardens. Stream or pond peripheries. A good plant for covering a wet low spot where nothing else will grow. Interesting plant for large patio containers. Provides strong vertical accent to any planting.
Information adapted from: Missouri Botanical Garden