I often get questions from folks who are curious about how plant nurseries propagate and grow bamboo plants. Bamboo plants are very easy to plant and grow in the landscape, but they aren't the easiest of plants to propagate. If we could simply collect and grow them from seeds it would be easier, but temperate bamboo typically only produce seeds about every 75 years, and the viability of the seed is short. Storage life is short, even under the best conditions. This leaves three ways that nurseries use to propagate temperate bamboo: from divisions, culm cuttings, or rhizome cuttings.
How Bamboo Plants Grow
Before getting into the details as to how nurseries propagate and grow bamboo plants in nursery pots, it's important to know a little about how they grow in the ground.
Every spring, bamboo plants produce new canes, what some folks call culms, which first emerge from the ground as elongated, cone-shaped "shoots" that rapidly grow to form the cane and leaves. These shoots emerge from underground rhizomes, which some call creeping root stalks. A rhizome is actually a horizontal underground plant stem capable of producing the shoot and root systems of a new plant.
Bamboo plants grow differently than other plants. While the trunks and branches of most plants continue to grow larger year after, the shoots of bamboo will grow in height and diameter for around 60 days after the shoot emerges, during which time the cane produces limbs and leaves. After this 60-day growth cycle, the cane will never increase in diameter or grow taller, though it continues to live on. Its energy is then used to expand the root structure and produce more plants that will form a colony, or what most of us call a grove. The new plants will grow in the same manner as the original plant; emerging as a shoot from the underground rhizome and rapidly growing for 60 days to form a new cane with limbs and leaves. With each passing year, the new canes produced in spring will increase in number and grow taller with larger diameter canes.
Bamboo Growth Rate Pattern
Depending on the species it takes a varying number of years for bamboo to reach their maximum height and cane diameter. For example, it can take giant bamboo species, which can attain mature heights of 50 feet or more, several more years to reach maturity than it does a shorter growing bamboo. Climate, cultural conditions such as soil type and sunlight, and fertilization and water are factors that can speed up or slow down the growth rate.
Bamboo has an amazing growth rate that has been measured at up to 4 feet in a 24 hour period during the spring shooting period. When the new shoot reaches its height, it will unfold its branches and new leaves.
Though bamboo is known to be one of if not the fastest growing plants in existence, it will take a few years for a newly planted bamboo plant to form a grove appearance. The growth process can be compared to plants such as English ivy, which "creeps the first year, crawls the second year, and leaps the third year." For example, a 3 gallon size Phyllostachys species will usually have 1 to 3 shoots. The following spring, each of those canes are capable of producing a couple more canes. The effects of compounding growth really become evident the third spring when all those canes produce more growth. The grove will become more impressive each year as the canes will be larger in diameter and taller.
How Nurseries Grow Bamboo Plants
Needless to say, because most bamboo plant growers grow their potted plants from divisions or rhizome cuttings, they must have a bamboo grove from which the divisions or cutting will come. Therefore, nurseries that propagate and grow many species of bamboo will have many bamboo groves on their property, one for each species or variety.
Most of our bamboo plants are transplanted from the grove to nursery pots during the dormant season, before new canes are produced. The best time to propagate from existing clumps is just before growth begins in spring. We transplant hardy species in late winter or early spring and tropical ones in late spring or early summer. Transplanting at other times is possible, but the risk of losing divisions in summer heat or winter chill is high
For transplanting to shippable size containers 1 to 3 gallon in size, we usually use rhizome cuttings. Depending on their size, larger rhizomes go in a 2 or 3 gallon pot while smaller rhizomes go in a 1 gallon pot. The rhizomes of larger species, such as giant bamboo, will almost always require a 3 gallon size pot or larger. For clumping bamboos, the cutting consists of the rooted base of a culm(s); for running bamboos, it is a foot-long length of rhizome with roots and one to several buds.
We plant bamboo in rich soil mix with ample organic material. If plants are tall, we sometimes cut back tops to balance loss of roots and rhizomes, and to make it possible to ship them in a box that is under 6 feet in length. Shipping is already expensive, but for every foot over 6 feet carriers charge an extra $50 or more for shipping!
Depending on the time of year you purchase a potted bamboo, you may or may not see any new growth after planting it in the ground or a pot. By the time summer arrives, most bamboo species will have developed all their new shoots for the current year, which is usually one to several shoots. By mid to late summer the 60-day growth cycle will have ended and foliage growth will have ceased for the current year. If you purchase a bamboo plant from a nursery in summer and wonder why it's not growing, this is explains why. The plant has completed its annual growth cycle and will not send up new shoots until the following spring or summer.
Note: Depending on species, the size of the rhizome used, and how long the bamboo plant has been growing in the nursery pot, only one to several new shoots will have emerged in spring. When you purchase a container-grown bamboo plant that might appear to be "small," it should not be thought of as an individual plant but one with underground stems (rhizomes) that are growing and will send up the shoots that become a colony or grove.
How To Accelerate Bamboo Growth
Bamboo plants do not require fertilizer however benefit from it. Fertilizer helps to accelerate growth and greatly reduces the time it takes bamboo to create a privacy screen or achieve a mature size. Because many soils have nutrient deficiencies, I suggest the application of a well-balanced time-release fertilizer on plants growing in the ground. I use Fertilome Tree and Shrub Food.
Other Helpful Bamboo Tips
New plant growth or shoots will initiate around March and extend through May for Phyllostachys bamboo in the Northern Hemisphere. During this time these new shoots are very tender and can be broken by the slightest bump. So be careful when walking nearby your bamboo plants in spring. That said, if you want to control the spread of your bamboo, simply break off these new shoots.
Bamboo is not picky about soil conditions, but optimal soil conditions can accelerate growth rate. Optimum soil pH is 6.8 to 7.2. Bamboo like most plants performs better with when mulched with organic matter such as leaves, pine straw or shredded wood mulch. Avoid a thickness of more than 2 inches. With the exception of wetland bamboo varieties, most others prefer a moist but well-drained soil. Constantly soggy can be problematic causing root rot. That said, most bamboo grow well in clay and average soils.
With the exception of shade-loving bamboo species, sun-loving bamboo species will grow faster the more sunlight they receive. Too much shade and plants won't grow as large and full. We suggest at least 4 hours of sunlight for optimum growth and overall performance. More is better. That said, make sure to check the sunlight preferences for each different variety before choosing a planting location.
If you are wanting to create a privacy screen or hedge rapidly, we suggest planting bamboo plant on 5 foot centers or closer, which means from the center of one plant in the row to the center of the next plant. Visit our article titled How Far Apart To Space Bamboo Plants For A Hedge Or Privacy Screen
Hope this information is helpful. If you need more details or have any other questions contact us.
Plant Long & Prosper!