“Twitching cocoons” on a Leyland cypress are probably bagworms. The cocoon is generally broadest in the center, narrowest on both ends, and covered with vegetation from the host plant. Bagworms occur throughout North Carolina. Bagworms are usually found on conifers such as arborvitae, spruce, juniper, cedar, and Leyland cypress. However, bagworms have a very wide host range and can feed on many plant species including deciduous trees and shrubs.