There are two main varieties of Bamboo: Clumping and Running.
Clumping bamboo is the slower-growing type of the two and has a shorter rhizomatous root structure than the running variety. This means the bamboo roots are unable to expand by more than a few inches each year and will form new culms (stalks or canes). This type of bamboo grows between one to three feet in height per year as long as it has enough space to grow. Some species will grow to 10 feet or more when they mature. Even though this type of bamboo does spread, it is much easier to control than fast-growing running bamboo and can be shaped by removing new shoots as they appear from the soil.
Running Bamboo, as the name suggests, sends out rhizomes (runners or root stems) in the soil from the parent plant. These rhizomes will grow through the soil at a depth of anywhere between 2 and 18 inches deep. This type of bamboo is commonly used to quickly grow natural cane screens and hedges because they will grow to fill the gaps between the parent plants.
Whichever type you own, your bamboo will need to be managed correctly if you want the bamboo to grow without becoming an issue.
Bamboo Control – How to Prevent it from Spreading
Running bamboo spreads at a much faster rate compared to clumping bamboo.
The best way of controlling running bamboo is to install an effective physical subsurface barrier or root barrier around the perimeter of the plant. Bearing in mind that the rhizomes will grow underground at a depth of up to 18 inches, you need to make sure the containment barrier is between 2 feet and 3 feet deep. Dig a trench all the way around the growth area that will accommodate the barrier, and make sure the barrier is between 3 and 4 cm in thickness. We recommend the barrier is constructed from plastic rather than cement or metal because cement is prone to cracking and metal can corrode, allowing the rhizomes to find a way through and past the barrier.
A properly installed barrier will deflect the rhizomes, so they quickly become visible above ground, and you will then be able to sever the rhizomes and eradicate the problem. Remember to check the top of the barrier regularly and cut back any of the bamboo rhizomes that try to grow over the top. This will prevent any unwanted spread and control the bamboo and stop it from getting out of hand.
Pruning Bamboo Shoots
Pruning (cutting the bamboo) is effective when you want to control the size or height of clumping bamboo whilst still keeping its look. Pruning can be done by removing new shoots at ground level or unwanted stalks that are larger in diameter than the stalks (culms) that have already reached the desired height. Bamboo growth is at its most active during the spring months and this is when you need to prune any shoots or new growth that you don’t want.
For running species’ of bamboo, you will need to perform some root pruning and sever the roots (rhizomes) that are interconnecting the main bamboo plant to new growth. Barrier installation (discussed earlier in this article) will help keep bamboo from invading areas it should not be growing.
If the bamboo is actually spreading to a lawned area, you can prevent it from spreading by regularly mowing the area where the shoots are growing up through the turf.
Potted Bamboo Plants
A simple but effective method of controlling bamboo from spreading, if you haven’t already planted it, is to grow the bamboo in a large gardening pot. The pot is an effective ready-made barrier to keep your bamboo under control and you will only need to check for rhizomes growing through the water holes or over the top of the pot.