Horsetail Grass is also called shavegrass and is naturally high in silica, a mineral that strengthens hair, skin and nails. Horsetail Grass is a very mild diuretic and astringent, making it a gentle healer for such conditions as cystitis or an irritated bladder. It also has the ability to dissolve sediments such as stones in the kidneys or bladder. There are many varieties of horsetail grass, most growing in damp to wet conditions. If you have a water feature in your yard, you could grow horsetail grass. It is said that because of its high silicon content, pioneers used it to scrub metal pots after use.