How to Grow and Care for Horsetail

Horsetail, also called rough horsetail or scouring rush, is a non-flowering evergreen perennial grown where other plants fail. It has hollow vertical green stems with horizontal bands similar to bamboo, but they’re skinnier and taller like ornamental grass. Similar to ferns, horsetail reproduces through spores and underground rhizomes. Horsetail adapts to many growing conditions and is impervious to diseases and pests. It grows fine in full sun or part shade, neutral or acidic soil, and though it thrives in humidity, horsetail tolerates any temperature.

Horsetail is usually planted in early spring, though it will survive planting at almost any time. This fast-growing plant achieves full height within a matter of weeks. If not contained, it can take over quickly. Horsetail is toxic to grazing animals.

Horsetail Care

Here are the main care requirements for growing horsetail:

• Plant horsetail in open areas where other plants can’t thrive, and it will quickly fill in space.
• Contain horsetail, if desired, by installing plastic barriers in the soil or planting it in a deep pot buried in the ground.
• Plant horsetail in wet conditions and even in standing water, such as water gardens or swampy areas.
• Water horsetail daily if not planted in wet conditions, though the plant can handle some drought conditions.

Light

Horsetail is extremely adaptable to various light levels, growing in every condition, from full sun to partial shade. That being said, it prefers filtered shade, such as that found on the forest floor beneath tall trees.

Soil

Horsetail thrives best in poor, sandy, gravelly soil that is frequently wet. When growing horsetail in a container, consider adding gravel or sand to the potting mix to give it the texture the plant enjoys.

Water

When it comes to soil moisture, horsetail prefers soil that is at least moderately wet. It can even grow in standing water up to a depth of about 4 inches. Thus, it’s well-suited for rain gardens and other areas that may periodically flood. Because of this love of water and moist soil, horsetail should be watered frequently and never allowed to dry out. In warmer climates, this can even mean watering daily.

Temperature and Humidity

Horsetail plants prefer high humidity for several hours a day and thrive in a variety of temperatures. Winter care is not a concern, as the plant is hardy to USDA zones 4 to 9, though the bright green of the stems may fade during especially cold winters.

Fertilizer

In general, horsetail plants do not like particularly rich or fertile soil, so fertilizing is not necessary.

Types of Horsetail

Although there are no direct cultivars of Equisetum hyemalis, there are several related species also known as horsetail. Some of the most popular options include:

• Equisetum arvense: Commonly known as field horsetail or corn horsetail, this plant is generally categorized as a weed because it is every bit as aggressive as E. hyemale but lacks aesthetic qualities for landscaping. Field horsetail can grow up to 20 inches tall, but it’s often stunted by the dryness of the earth in which it grows, so that it reaches only about 8 inches tall or less. Many landscapes become overrun with field horsetail, and it spreads even under the driest conditions.
• Giant horsetail (E. giganteum): A Central- and South-American native, this plant is only hardy to zone 8. It can be grown in full sun or partial shade and can become 10 feet tall or more.
• Variegated horsetail (E. variegatum): This shorter, hardier plant is native mainly to the wetlands of the northern United States and Canada. It’s termed “variegated” because its black-and-white sheaths (on otherwise green stems) show up better than those on E. hyemalis.

Pruning

While horsetail isn’t pruned in the traditional sense, the main challenge is keeping this plant under control or eradicating it where it is not wanted. Horsetail can extend its roots under sidewalks, garden walls, and driveways, so elimination requires carefully digging up and removing all root pieces, but even that may not always work.

It may also be possible to eradicate horsetail gradually by cutting the reed-like stems back to ground level as they appear. This can take several seasons before the plant surrenders and dies back completely. Finally, you can use a systemic herbicide containing triclopyr, which will kill horsetail. It may, however, take multiple applications before you completely eradicate the plant.

Propagating Horsetail

A gardener rarely wants to propagate horsetail since containing or eradicating this fast-spreading plant is more often the challenge. However, if you do want to share plants, it is an easy matter to cut away portions of the rhizomatous root clumps and replant them wherever you want. Spring is the best time to perform this action.

Common Problems With Horsetail

Horsetail is a tough and easy-to-grow plant, but it can cause problems if it spreads too aggressively. Horsetail spreads by spores or rhizomes, and its overgrowth can upend hardscapes, invade lawns, and crowd out other plants in your garden. To control the spread of rhizomes, plant in a container, below or above ground, without drainage holes. Horsetails also sprout cone-shaped fruits that contain many tiny spores that can increase their spread. Snip off the fruiting stems before they ripen and dispose in a sealed bag.