Water plants don’t get any easier than horsetail, which tolerates a wide range of soils and even grows in standing water. And although it prefers full shade, it can grow in full sun to part shade, too, as long as conditions are right. It’s not surprising to find out horsetail is so tough: This plant has survived—and thrived—since prehistoric times. The good news is it adds unique structure and texture to water gardens with its segmented hollow stems that are ringed in black and resemble thin bamboo. The bad news is that horsetail is incredibly invasive, and it’s tough to eradicate.
Horsetail’s good points include its ability to add interest to the landscape, even in winter. It’s particularly well suited to water gardens, bog gardens, tub or trough gardens, the edges of streams and ponds, and covering a boggy area where nothing else works. Grow lofty horsetail alongside surface-hugging water lily and water hyacinth. Or plant it in pots and enjoy its attributes in a confined growing location where it is less likely to displace nearby vegetation. Horsetail will provide a strong vertical accent in any of these locations.
How to Care For Horsetail
Horsetail spreads rapidly when planted in the ground and will overtake nearby cultivated and wild areas. It spreads by underground rhizomes found up to 3 feet below the soil surface as well as spores that burst open and germinate in the soil. The most responsible way for most gardeners to grow horsetail is to plant it in a container, which will prevent the plant's rhizomes from spreading—but that won't stop the spores.
This plant grows best in full shade but will grow in full sun or part sun as long as the soil is consistently moist. Sandy or gravelly soil promotes rapid growth, so incorporate sand or gravel into a traditional potting mix to prepare the container. The more fertile and humus-rich the soil, the more slowly horsetail grows.
Horsetail is one of the oldest plants on earth. And for good reason: It's tough to eradicate. Chemical control may be the best option for completely removing the plant from an area. A systemic herbicide, such as triclopyr, is an option if the plant is not growing in water. Be sure to follow label directions exactly. You may have to apply it more than once. Check with your local DNR office with questions about wetland uses.
If you're patient, you can try repeatedly eliminating the top growth to prevent spores from germinating. It may take years, but in theory the plant will eventually die out. Another chemical-free option is to alter the growing conditions by making the site inhospitable to this ancient plant. Improve drainage to take away the wet conditions loved by horsetail. Boosting the soil's nutrient content will deprive the plant of the poor, infertile soil it prefers. Don't try digging up this plant; you will undoubtedly leave behind tiny pieces of root that will sprout into whole new plants.