“Snake grass weed,” officially known as field horsetail (Equisetum arvense), is a common and often frustrating presence in gardens. Its persistent nature and ability to rapidly spread make it a formidable challenge for many gardeners seeking to maintain healthy plant beds.
Identifying Snake Grass Weed
Identifying snake grass is the first step in managing its presence. This plant possesses a unique appearance that distinguishes it from other garden weeds. Its stems are segmented and hollow, often resembling miniature bamboo or small fir trees, and can grow up to two feet tall.
Snake grass exhibits two distinct types of stems throughout its growing season. In early spring, light brown, unbranched fertile stems emerge, typically growing up to a foot tall and topped with a cone-like structure that produces spores. After these fertile stems release their spores and die back, the more numerous green, branched sterile stems appear, persisting through the summer. These sterile stems are grooved and hollow, with whorls of feathery branches at their joints, giving them a bushy appearance. Snake grass often indicates specific soil conditions, as it thrives in wet, disturbed, or poor soils, preferring acidic and infertile environments.
Why Snake Grass is a Garden Nuisance
Snake grass poses a significant challenge due to its persistent characteristics. It develops an extensive, deep rhizome system, which can penetrate the soil up to six feet or more, making manual removal incredibly difficult. These underground rhizomes store carbohydrates, enabling the plant to regenerate vigorously even after its above-ground growth is removed.
The plant’s rapid spread occurs not only through its rhizomes but also via spores produced by its fertile stems. These spores can be dispersed by wind, allowing the weed to colonize new areas. Furthermore, snake grass is notably resilient to many common herbicides, partly because its stems and leaves contain silica, which creates a waxy, abrasive surface that makes herbicide absorption difficult. It flourishes in compacted, waterlogged, or nutrient-poor soils.
Controlling Snake Grass Effectively
Controlling snake grass infestations requires a persistent, multi-pronged approach. Manual removal should focus on consistently depleting the plant’s energy reserves rather than attempting to dig out the entire rhizome system, which can be extensive and regenerate from small fragments. Repeatedly cutting or pulling the green stems whenever they appear above ground, ideally every few weeks, helps to exhaust the plant over time. This consistent removal prevents the plant from photosynthesizing and replenishing its underground carbohydrate stores.
Implementing cultural practices can significantly reduce the weed’s vigor. Snake grass thrives in poorly drained, acidic, and infertile soils, so improving soil conditions can make the environment less hospitable. Enhancing drainage by filling low spots or installing drainage can help, as can boosting soil fertility with organic compost or aged manure. Raising the soil pH with agricultural lime can also inhibit its growth.
Chemical control can be considered for severe infestations, though it requires careful application. Herbicides containing active ingredients like glyphosate or triclopyr can be effective, but multiple applications are necessary due to the plant’s resilience. Apply these herbicides during late summer when the plant is actively transporting nutrients to its roots. Follow all label directions, use personal protective equipment, and apply carefully as a spot treatment to avoid harming desirable plants. Some advise bruising the stems before application to improve herbicide absorption through the plant’s waxy surface.
Smothering is another technique that can weaken snake grass by depriving it of sunlight. Applying thick layers of opaque materials, such as heavy-grade mulch matting or cardboard followed by mulch, can suppress growth. For this method to be effective, the covering must remain in place for at least one to two growing seasons to thoroughly exhaust the underground rhizomes. However, some sources suggest that smothering with black plastic or certain mulches may not be effective, as horsetail can thrive in wet, dark, low-oxygen conditions, and may re-emerge once the cover is removed.
Preventing Future Snake Grass Growth
Preventing snake grass re-establishment or spread involves proactive measures. A thick layer of mulch, such as wood chips or straw, can suppress new growth from spores and emerging rhizomes by blocking sunlight. While some debate its effectiveness for current infestations, a substantial mulch layer can be a barrier against new colonization.
Continually improving soil health is a foundational preventive strategy. Ensuring good drainage and maintaining balanced soil nutrients makes the garden less welcoming for snake grass, which prefers wet, poor, and acidic conditions. Regular additions of organic matter can enhance overall soil structure and fertility, supporting desirable plants that can outcompete the weed.
Vigilance is important in preventing future outbreaks. Regularly monitoring garden beds and promptly removing any new shoots as soon as they appear is important. Early intervention prevents the plant from establishing a strong root system and replenishing its energy reserves. For areas prone to re-infestation, consider barrier methods such as installing landscape fabric or root barriers. These can physically impede the spread of rhizomes from adjacent areas or contain existing patches.