Bamboo is a grass that has a range of varieties, such as tiny grass bamboo growing only a few inches high and the giant timber bamboo growing up to 25 feet tall. It is one of the world's fastest growing plants, second only to the Pacific giant kelp. Like many grasses, bamboo grows and spreads through underground rhizomes either in clumps or in lateral runners. While bamboo is a fast growing plant, some varieties grow faster than others.
Green Hedge bamboo, Bambusa multiplex, is a clumping bamboo that has a dense growth habit. It will block a view in two years and be thick and impassable in four years. It grows between 15 and 45 feet tall very quickly, with slender culms (poles) of little thicker than one inch. It is a tender bamboo for subtropical climates, hardy in U.S. Department of Agriculture zones 9a and 10.
Seabreeze bamboo, Bambusa malingensis, is a clumping bamboo that grows up to 35 feet tall with culms 2 to 3 inches in diameter. It has small, dark-green leaves that grow profusely each year, and grows well in coastal areas similar to its native habitat of coastal China. It is a tender bamboo, only hardy in USDA zones 2 and 3. It is a fast growing bamboo that will quickly fill in and screen an area once established.
Giant Timber bamboo, Phyllostachys, has many varieties in a multitude of colors, sizes and variegations. It grows between 20 and 70 feet tall, with very thick culms. Phyllostachys is a running bamboo and will multiply quickly if not controlled with root pruning or barriers. It is a good screening or specimen bamboo hardy in USDA zones 6 to 10. The harvested canes are very strong and durable, useful for building and crafts.
Windbreak bamboo, Bashania fargesii, grows up to 25 feet tall with culms 2 inches thick. This variety is very flexible yet strong in the wind, with thick, long leaves. It is a running bamboo, with a strong rhizome system that controls erosion and spreads quickly. It is hardy in USDA zones 7 to 10.
Green Temple bamboo, Semiarundinaria fastuosa, is a large hardy bamboo that grows up to 35 feet high. It has an upright growth habit and is hardy in USDA zones 6 to 10. It is very wind resistant and tolerant of ocean salt air. Although slow to establish, it is a fast grower after the first year or so. Green Temple bamboo is grown for tall privacy screens and for large indoor specimens.