Understory refers to the area that is under the taller trees. It is below the tree canopy but is not the forest floor. In addition to housing a number of shade-tolerant plants, the understory is also home to a number of animals. Plants that live in the understory are generally short even though they may be old. Understory plants include shrubs, small trees, flowers and vines.
Heliconias (Heliconia) are tropical understory plants native to the Americas and the South Pacific. They have leaves similar to banana tree and bright, long-blooming inflorescences of showy bracts with the true flowers inside. The heliconia plant family consists of only one genus with about 200 to 250 different varieties. In its natural habitat heliconias occur in the humid, tropical forest understory and along rivers. The plants have a rapid growth rate and thrive in fertile soil. Heliconias are propagated with rhizomes and grow best in warm, shaded areas. The plant stops growing during dry or cool weather and resumes growth in moist, warmer temperatures.
The cacao tree (Theobroma cacao) is a small-sized understory tree that thrives in the shade of heavier canopies and grows to a mature height of about 50 feet. Cacao tree is a native of the American tropical rain forest and its natural habitat is the Amazon basin riverbanks. The tree is tolerant of heavy shade and needs moisture to grow optimally. Cacao trees are deciduous and have bright green, oblong foliage. The leaves that are continually shaded are longer than the ones getting some amount of light. The trees prefer well-drained, slightly acidic soil and grow best in areas of moist shade. The fruit of the cacao tree is the raw material for chocolate.
Chinese witch hazel (Hamamelis mollis) is an understory tree, 10 to 15 feet tall, that requires shade to grow well. Chinese witch hazel is often assumed to be a large shrub, however it has a distinct treelike shape. The tree blooms with yellow flowers during February and March and has a spread equal to its height and a round form. Chinese witch hazel grows best in rich, acidic soil and is resistant to most pests and diseases. Japanese witch hazel (Hamamelis x intermedia) is another large shrub or small-tree variety of Chinese witch hazel that is commonly grown as ornamental and specimen plantings.