Clumping bamboo is composed of over 500 species, and is less adaptable than the running bamboo species. The vast majority of clumping bamboo species grow in the tropical, and sub-tropical regions around the world, however, several species will grow in the southern United States, zones 7 - 10. Clumping bamboo, as the name suggests, grows into large grass-like clumps with the stalks growing tightly together, and expanding 360 degrees outwards, to reach a diameter of 10 - 15 feet.
Generally, clumping bamboo is thought to have smaller diameter poles than running bamboo, because the varieties growing in the U.S. have grown to diameters of no more than 2 ½ inches. This observation, however, is a misconception, because some of the largest bamboo in the world is found in the clumping bamboo cultivars, but those species are only found in the tropics or sub-tropical regions. Of the 500 plus species of clumping bamboo, the genus, Bambusa, is the most wildly grown in the lower United States. Clumping bamboo is also grown for many of the same products as running bamboo, and accounts for the majority of paper pulp production, actually taking place today mainly in India. The Bambusa family is comprised of many species, but a few of the more widely planted bamboo varieties in the U.S. are Bambusa multiplex varieties, commonly known as 'Hedge Bamboo.' The primary species are Bambusa multiplex 'Alphonse Karr', Bambusa multiplex 'Golden Goddess', and Bambusa multiplex 'Weeping Willow' bamboo.
Bambusa multiplex "Alphonse Karr" bamboo grows variegated, bright yellow stalks with green pin-stripes. Alphonse Karr grows fast to 1 -2 inches in diameter, and poles up to 50 feet tall. Alphonse Karr striped bamboo was named in honor of the French botanist-novelist, of the nineteenth century, who admired this beautiful specimen plant of striped bamboo.
Bambusa multiplex "Golden Goddess" bamboo is the most popular hedge bamboo used in the U.S.. Golden Goddess bamboo has a solid bright yellow-gold stalk with beautifully contrasting small green leaves. The stalk grows fast to more than 2 inches in diameter and grows to a height of 40 feet. The contrast between golden stalks and green leaves is unparalleled, and the reason for its popularity. Golden Goddess bamboo is also popular, because it lends itself to pruning to the landscape height you desire to grow.
Bambusa multiplex "Weeping Willow" bamboo is fast growing in popularity across the south, for its graceful arching outer stalks, under which many Southerners relax on their patio furniture. Its stalks grow from ¾ - 1 ¾ inches in diameter, and to a fast height of approximately 35 feet. Weeping Willow bamboo has green stalks with a greenish-blue hue after aging, which gives it a fascinating emerald sheen. Weeping Willow bamboo grows so dense at maturity, that not even a rabbit could penetrate through its and thick clumps.
These clumping bamboo species are, like the running bamboo, not particular concerning soil type and the amount of sunlight required. Clumping bamboo trees are planted for use as tall hedges, privacy screens, windbreaks, or for their ornamental beauty. Clumping bamboo is primarily prized for its non-invasive characteristic, which allows this bamboo to be used as barriers between homes in densely populated urban communities.
All of the previously mentioned running and clumping bamboo are of Asian origins, however, there are two native American bamboo varieties as well. Arundinaria gigantea, also known as "canebreaks" or "switchcane" that once covered vast areas from Virginia down to Florida, and West to Texas. This American native bamboo was once so densely populated, that it provided an effective refuge and exit for runaway slaves from the South headed North to join the Union Army. Arundinaria gigantea was an excellent forage crop for early settlers. It's demise came from uncontrolled grazing; removal processes that accompany logging, the growing lumber industry, and wild fires. Native American bamboo rarely grows greater in diameter than 1 inch, and 25 feet tall, with very large leaves on fast growing poles. American native bamboo is technically a running bamboo, but not nearly as aggressive, growing very densely and spreading very slowly, so that little clues remain that was once a vast under story of native American bamboo.