Justicia is a genus of about 420 species of flowering plants in the Acanthus family. Sometimes called shrimp plant or water willow, Justicia plants are native to tropical and temperate areas of Asia and the Americas. All but the two northernmost species are limited to warm habitats. Many Justicia species are grown ornamentally, and some have medicinal uses.
J. americana, or water willow, is the hardiest of the Justicia species, able to grow as far north as Alaska. It is an aquatic plant, growing in still or moving bodies of water. Its flowers are purple to white, and bloom from late spring through early fall. J. americana often forms large colonies near the shorelines of lakes or rivers.
The other Justicia species that grows in cooler climates is J. californicus, commonly known as chuparosa or hummingbird bush because the plant is mainly pollinated by hummingbirds. It is native to the deserts of northern Mexico, southern California, and Arizona. J. californicus features succulent leaves, which fall off to be replaced by bright red, tubular flowers. It is a popular ornamental plant in desert regions, both for its beauty and for its ability to attract hummingbirds.
J. brandegeeana, commonly called Mexican shrimp plant, is native to Guatemala, Honduras, and Mexico. It has also been naturalized in Florida. Its bright red leaves tapering to white flowers are thought to resemble shrimp.
This type of Justicia is cultivated as an ornamental plant. It is low maintenance, tolerant of drought, and does not require fertilization. It does best in the shade, and an be grown both indoors and out. Mexican shrimp plant prefers loamy or sandy soil, and should be trimmed back regularly to prevent heavy branches from drooping.
J. adhatoda, commonly called adulsa or Malabar nut, grows in India, Nepal, and Pakistan. It is the provincial flower of Punjab in Pakistan. The alkaloid vasicine, present in the leaves of J. adhatoda, is used in pharmacology to relax and dilate the lung passages and to treat inflammation of the lungs.
Another species with medicinal properties is J. pectoralis, native to Latin America and the Caribbean. Its common names vary by country and include chapantye, curia, masha-hiri, and tilo. J. pectoralis has similar uses to Malabar nut in folk medicine, where it is often used to treat influenza. J. pectoralis also has hallucinogenic properties in certain preparations. It is used in religious ceremonies by shamans of the Craós tribe in Brazil.