Horsetails reproduce by spores and do not have flowers; their green spores are produced in a flesh-colored cone at tip of fertile stem. Its thick stands of shoots can choke other plants and requires prolonged effort to remove from sites due to rhizomes. The fertile stems of common horsetail appear in early spring before the vegetative stems have grown tall enough to block spore dispersal by the wind. The spores have appendages on them that curl when wetted and uncurl when dried, which helps disperse the spores and move them deeper in the soil.