Lonicera maackii

Lonicera maackii, the Amur honeysuckle, is a species of honeysuckle in the family Caprifoliaceae that is native to temperate western Asia, specifically in northern and western China south to Yunnan, Mongolia, Primorsky Krai in southeastern Russia, Korea, and, albeit rare there, central and northern Honshū, Japan. Lonicera maackii is enumerated as an endangered species in Japan. It has escaped from cultivation and naturalized in New Zealand and the eastern United States; in the woodlands of the latter it is a significant invasive species. The plant is a large, deciduous shrub that grows a maximum of 6 m tall with stems of a maximum of 10 cm in diameter. The leaves are oppositely arranged, 5–9 cm long and 2–4 cm broad, with an entire margin, and with at least some rough pubescence. The flowers are produced in pairs, and commonly several pairs are produced together in clusters; they are 2 cm long, have two lips, begin white and later turn yellow or pale orange in color; they bloom from middle of spring to early summer. The fruit is a bright red to black, semi-translucent berry, 2–6 mm in diameter, that contains numerous small seeds; they ripen in autumn and are eaten by birds, which disperse the seeds in their droppings. It grows rapidly and prefers shady habitats such as woodland understories, neglected urban areas, and fence rows. It can form very dense thickets. Amur honeysuckle is cultivated as an ornamental plant for its attractive flowers and as a hedge. Many cultivars have been selected for horticulture, including 'Erubescens' with pink flowers and 'Rem Red' with an erect form. The flowers are sometimes savored by children, who remove blossoms and pull off their bottoms so as to suck out the sweet nectar in the centers. However, the berries are mildly poisonous to humans and therefore should not be consumed. Propagation of this plant is illegal or controlled in some of the United States, where it is an alien species, because of its well documented invasive nature. The species is named 'invasive, banned' in Connecticut, 'prohibited' in Massachusetts, as an invasive species in Tennessee, as an invasive species in Ohio, as a 'Class B noxious weed' in Vermont, and as an invasive species in Wisconsin. This plant is adaptable and flourishes in a wide range of conditions. In the United States, it was historically planted to control erosion and in hedges. It propagated itself rapidly by avian dispersion of its seeds and soon thereafter naturalized. Notably, in the understories of deciduous woodlands of the eastern United States it forms dense thickets, the shade of whose canopies prevent the growth of native shrubs, juvenile trees, and wild flowers. Uncontrolled, these growths result in almost monocultural thickets of Amur honeysuckle. The species gravely jeopardizes not only the diversity of the invaded ecosystems but even the regeneration of woodlands, because it reduces the growth and diversity of native seedlings. Additionally, studies indicate that it negatively affects birds and tadpoles. Even if its shrubs are removed, the affected habitat may not recover absent substantial human effort. A study conducted in the vicinity of St. Louis, Missouri in 2010 indicated that the plant increases the risk of tick-borne diseases such as Erlichiosis and Lyme disease in suburban natural areas by attracting deer and consequently increasing the presence of infected ticks. Furthermore, experimental removal of the plant was shown to reduce deer activity and the number of infected ticks by shifting ticks' blood meals from deer.