The horsetail, Equisetum hyemale, is a primitive perennial. It has a dark green, segmented stem and does not grow leaves. Some horsetail plants may have whorls of branches instead of a singular stem, but only the plant with the singular stem produces the cone-shaped body at the top. This cone-shaped body produces the spores that the plant uses to propagate itself. The horsetail is considered an invasive weed in most areas, but it is protected in Rhode Island.
Choose a planting spot near or in up to 6 inches of water, which is in full sun. If your pond does not have an area with full sun (more than six hours of sun every day), the horsetail will grow in partial shade.
Dig a planting hole as deep as the root ball on the horsetail plant, and twice as wide. Center the plant in the planting hole and backfill with soil. If you are planting in the water, move the silt with your hands while gently pushing the root down into the silt. Push the silt over the root ball.
Water well if the soil is somewhat dry. The horsetail prefers living in water, so if you chose a spot that is not in water, water the horsetail at least every other day with at least 1 inch of water.