What kind of weed
Horsetail, a primitive plant dating back to the dinosaurs. Horsetails represent an ancient family some 400 million years old. Before flowering plants evolved, forests of giant horsetails 90cm (3ft) around and 18-27 meters (60-90ft) tall grew over the Paleozoic landscape. Your picture is of the photosynthesizing part, The reproductive part is attached. It spreads by spores and by running rhizomes. . Another name for horsetail is scouring rush. It has a high content of silica and was used to scour pots and pans by the settlers and before them by the native inhabitants. It is also used as a tea to activate and enrich compost, as a foliar spray for plants to provide essential minerals and as an antifungal spray for the plants. Container plants adore horsetail tea. You do not want to chop it up and add it to your compost, however, as its powers of regeneration are awesome. It even functions as a companion plant, but if it is taking up too much space, the best control is to cut it to the ground as soon as it appears and remove the cuttings. It is highly resistant to home use herbicides in general.