Bamboos are a very broad group of plants, comprising more than 1,400 species in more than 70 genera. As a group, they share some superlative characteristics, including being the largest grasses and the fastest-growing plants in the world.
Because bamboo culms, the plant's woody vertical stems, grow to their full mature height within a single growing season, the fastest-growing bamboos are also the largest species. In ideal growing conditions, the tallest bamboos can reach heights of over 100 feet, and all that vertical growth happens within the course of just a few months.
Some of the biggest, fast-growing bamboos that can be grown in gardens in temperate climates belong to the Phyllostachys genus. One of them is Moso bamboo (Phyllostachys edulis), which is hardy in U.S. Department of Agriculture plant hardiness zones 6 through 9. In the best growing conditions, it can grow more than 3 feet in a single day and reach a mature height of about 90 feet, but in less-than-ideal conditions, it may grow more slowly and reach a height of only 30 feet.
Another member of the Phyllostachys genus is Chinese timber bamboo (Phyllostachys vivax), which is hardy in USDA zones 6 through 10. It can reach 60 to 70 feet in height but more typically grows 40 to 45 feet tall.
Black bamboo (Phyllostachys nigra) is also a fast grower, but it's somewhat more modest in size and may be more suitable for smaller spaces. It can grow about 30 feet tall and is hardy in USDA zones 7 through 10.
Bamboo species in the Fargesia genus are typically more cold-hardy than tropical bamboos and may be grown in moderately cooler climates. They don't rocket to towering heights the way that some of the giant bamboos do, but they can still grow to over 10 feet high in a single growing season and quickly form a screen or hedge. Dragon head bamboo (Fargesia dracocephala 'Rufa'), for example, typically grows to a height of 8 or more feet and is hardy in USDA zones 5 through 9.
Ideal Growing Conditions
Bamboos grow best in loose soil that is rich in nutrients and organic matter. The plants need plenty of water, but they have shallow root systems that are easily damaged by standing water or soggy soil. Planting bamboos in raised beds can help to improve drainage around the plants' roots in areas with heavy soil.
'Moso' bamboo, black bamboo and Chinese timber bamboo grow best in full sun, and they achieve their highest growth rates when temperatures are high. Dragon head bamboo tolerates partial shade.
A fertilizer high in nitrogen can encourage fast bamboo growth. At planting time, apply 2 1/2 pounds of an 8-6-4 or 10-6-4 fertilizer per 100 square feet of planting area. Apply the fertilizer again at the same rate each spring. Water the soil thoroughly after each fertilizer application.