Bamboo is an amazing plant that has gained a lot of popularity over the years due to its versatility and sustainability. However, it’s also known for its tendency to spread quickly (and sometimes far) when not properly contained.
If you’re growing bamboo at home or in your garden, you might be wondering how you can stop your bamboo from spreading. There are several manual techniques you can use to control your bamboo such as root pruning and shoot pruning. Additionally, one of the easiest and most effective methods to stop the spread of bamboo is simply to install a root barrier.
When people think of bamboo as an invasive plant that spreads too far too quickly, they’re most likely thinking of running bamboo. Unlike clumping bamboo, running bamboo can become invasive if left unchecked. So if you’ve got a patch of running bamboo in your garden, you should learn how to slow or even stop its spread. Let’s get into it!
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When do you need to stop bamboo from spreading?
If you know anything about grass, you probably know that it can sometimes grow like a weed. In fact, some bamboo is considered invasive for its tendency to spread far and wide in a matter of years when left unchecked, choking out native plants along the way. Luckily, not all bamboo types have an invasive growth habit, so you can choose one that best suits your needs and climate.
Types of bamboo: running vs. clumping
There are two main types of bamboo: running and clumping. Running bamboo can spread very quickly along its underground rhizome system which sprouts new shoots along its horizontal nodes. Clumping bamboo, on the other hand, produces new shoots on existing ones, meaning that its system stays ‘clumped’ and doesn’t spread the way running bamboo does.
For the most part, you don’t need to worry too much about clumping bamboo as long as it has room to expand. Running bamboo, on the other hand, requires some serious maintenance and control in order to prevent it from spreading beyond your garden or causing damage to existing structures.
Techniques to keep your bamboo growth in check
If you’re growing any kind of running bamboo, it’s important to learn how you can keep its growth in check. First, we’ll get into a few manual techniques you can use to keep your bamboo maintained and to stop it from spreading uncontrollably.
Root pruning
If you’re not afraid of getting your hands dirty, root pruning is a great method for reining in your bamboo’s rapid growth. Luckily, the superficial nature of bamboo rhizome systems makes this an easy first line of defense. Instead of going deep, bamboo rhizomes spread in loose topsoil about 2-5 inches below the surface.
If you can prune young rhizomes before they have a chance to produce shoots, the bamboo won’t be able to produce new canes. However, keep in mind that root pruning isn’t a permanent fix. New rhizomes will continue to emerge from the parent plant, growing up to 5 feet in a single year! For best results, you should plan to root prune about 1-2 times per year.
For effective root pruning, use a sharp spade to cut and remove the rhizomes that have spread beyond your desired growing area. Simply dig into the soil around your bamboo to cut the rhizomes. You can usually feel it when the spade cuts through it. If you leave some of the rhizome attached, new shoots (culms) can emerge in the spring. You can cut the rhizome back entirely if you would like to prevent any new growth in a specific area.
Digging up bamboo rhizomes can be strenuous, so you may want to consider combining this method with other control methods.
Helpful tips:
- To minimize the strain of root pruning, you can create an initial trench around your bamboo at the point where you want it to stop growing. Fill this trench with sand, this will allow you to easily cut back new rhizomes.
- Rhizomes usually start to develop after shoots have done most of their growing for the year, around midsummer. Rhizome growth will continue rapidly until early autumn. This is the best time to prune because the developing tips are soft and can be easily cut.
- Cutting a rhizome back when it reaches about 6 inches can stop another 5 feet of growth.
- Prune 1-2 times during the growing season (timing may vary between years depending on the weather).
Shoot pruning
Another effective technique you can use to remove excess growth from your bamboo is shoot pruning. This technique is similar to root pruning, but instead of targeting the underground rhizomes, you target the fresh shoots emerging from the ground. Shoot pruning can be used not only to limit the growth of your running bamboo, but also to prevent overcrowding within your bamboo grove, hedge, or barrier.
Shoot pruning is a simple approach and can help you stop new shoots from growing into mature canes. Note: this method alone won’t stop your bamboo from spreading horizontally, so it’s best combined with other methods such as root pruning or installing a rhizome/root barrier.
Shoots typically develop once a year in springtime, so this is the best time to prune them back. When shoots reach about 6-12 inches tall, they are still fragile enough to be knocked over or cut back using a spade or sharp clippers.
Helpful tips:
- Look for new shoots growing away from your mature plants. Sometimes all it takes is a good kick to extract some of the medium-sized shoots before they become established.
- For precision, use a spade or an axe to slice away the shoots neatly and effectively.
- Fresh shoots can be removed quickly using a lawn mower or weed eater, but keep in mind that this method is less precise and should be repeated regularly.
- Young bamboo shoots are edible, so you can choose to harvest them.
Installing a root barrier
Although root pruning and shoot pruning are great techniques to stop your bamboo from spreading uncontrollably, they can be a lot of work. An easy, effective, and long-lasting way to prevent excessive bamboo growth is simply installing a root barrier underground!
There are two main kinds of root barriers: open-sided and closed. We’ll get into both of these, as well as how you can install and maintain the barriers for maximum effectiveness.
What is a bamboo root barrier?
Bamboo root barriers are most commonly made from High Density Polyethylene (HDPE), a particularly strong type of plastic that is commonly used in plastic bottles as well as many other materials. Root barriers are usually about 18-48 inches tall, depending on the climate. For warmer climates, it’s important to choose a root barrier that’s at least 30 inches tall to keep those fast-growing roots in check.
Bamboo root barriers also come in various thicknesses ranging from 40 mil to 100 mil (for comparison, the average credit card is about 30 mil thick). We recommend that you choose a barrier that’s at least 60 mil thick in order to sufficiently block the thick bamboo roots. Bamboo root barriers are typically sold in 100-foot rolls and can be cut as needed.
Our Recommendation for bamboo barriers and clamps: Simply order them on Amazon!
Open-sided vs. closed barriers
An open-side bamboo barrier is a great option for responsible bamboo management. An open-sided barrier requires yearly root pruning on the side that’s left open. Generally, an open side simply implies no plastic root barrier on one side, whether in the form of a raised mound or trench. A closed barrier, on the other hand, means that the bamboo is surrounded on all sides with a bamboo root barrier.
Open-sided bamboo barrier systems are typically regarded as better for the long-term health of the plants, as it prevents the bamboo from being root-bound within a confined area. Additionally, leaving one side open encourages the bamboo to grow in that direction, making root pruning relatively easy and effective. Lastly, an open side allows for more drainage which can be good for an area that receives a lot of rainfall.
Open-sided barriers are often used to form a boundary along a fence line (and thereby maintain friendly neighbor relations). The bamboo barrier ends up looking like a half circle or U-shape.
Closed barriers can be a great option for smaller spaces, but keep in mind that the bamboo may become root-bound or find a way to grow through, over, or under the barrier in an attempt to keep growing. Keep the top few inches of the barrier exposed to make it easy to spot and stop any new growth.
Root barrier installation
Installing a new bamboo root barrier may seem like a daunting process, but it’s a great long-term investment for the health of your bamboo as well as your garden and neighboring gardens.
To install an open-sided barrier:
- Dig the U-shaped or half circle trench about 2 feet deep.
- Leave one side open and exposed for yearly pruning.
- Put the root barrier in the trench. The top few inches of the barrier should remain exposed since most new bamboo growth is within the top 4 inches of soil.
- Backfill the trench with sand or soil. Pack it down.
- Check the edge 2-3 times a year preferably in summer or fall.
- To prune back new growth, cut into the soil with a sharp spade and lift out any new rhizomes.
To install a closed barrier:
- Dig a 2-foot deep trench around the patch of bamboo and put the barrier in the trench.
- Use stainless steel clamps to attach the ends of the barrier. Then drill holes into each end to fasten the nuts and bolts of the clamp.
- The top of the barrier should remain exposed to spot any rhizomes attempting to escape the barrier.
- Fill the trench with sand or soil. Pack it down.
- For the top 3-5 inches, fill the trench with mulch instead of soil to make pruning easier.
- Prune back any new growth at least once a year.
Root barrier maintenance
Now that your bamboo root barrier is in place, you may be asking yourself how much maintenance it requires. Should you be checking for holes in the barrier? When does it need to be replaced?
Once installed, a root barrier requires a lot less work than if you were to do regular root and shoot pruning without a barrier. However, running bamboo can be quite tenacious, so new shoots and roots will find a way to get past or through your barrier over time. You can simply prune this growth back as you find it.
It’s easy to spot holes in an open-sided barrier, which you can then patch up accordingly. But what do you do with a closed barrier? Look out for suspicious new growth outside of the barrier, and if needed, dig back some of the soil to see if the barrier has been damaged. Although most barriers should be able to last a long time in the soil, they may need to be replaced if there’s too much damage.
Are containers effective at preventing bamboo from spreading?
Bamboo can be a fun option for container planting, but it comes with some real challenges, especially if you’re trying to grow running bamboo in a container. However, it’s possible and it’s a great way to stop bamboo from spreading.
A number of bamboo species are good options for growing in some kind of container, whether a large pot or garden bed. When choosing a container, make sure to choose one that gives your bamboo room to grow. With time, the bamboo can become root-bound and exert pressure on the container, causing cracks or even breaks. If possible, perform regular root pruning with a sharp spade or saw.
Can I use sheet metal instead of root barriers?
If you don’t want to use traditional bamboo root barriers, you can use sheet metal instead to rein the growth of your bamboo. To create a homemade bamboo root barrier with sheet metal, you do the same thing as you would otherwise and dig a trench around your bamboo. Sink the sheet metal at least 2 feet deep and leave the top exposed. Separate sections should overlap to prevent new growth from simply pushing through the gaps.
As you can see, there are a number of ways to stop bamboo from spreading and becoming invasive. Whatever method you’re going to use, make sure to be safe and wear the appropriate gear such as glasses and gloves.
One Comment
I installed a heavy plastic root barrier around my 5 year growth of bamboo taken from a root graft from a friends house. I trim my bamboo runners in February, July, and a checkup in November. I’m in the North East so we sometimes get some warm winter days. Today was cool and rainy so I did my early summer pruning and barrier check to make sure my bamboo isn’t getting into the neighbor’s yard. Success so far except for a few germinated seeds, but I plucked those out. Your website is very helpful! Thank you!