Square Bamboo or Square Stem Bamboo is a breathtaking, cold-hardy running bamboo with an unusual appearance. As the name implies, its culms are square-shaped rather than round! This interesting bamboo isn’t as invasive as most running bamboos, making for a delightful ornamental plant or privacy screen that is easy to care for when planted in the right spot.
Quick Facts
- Common name: Square Bamboo, Square Stem Bamboo
- Botanical name: Chimonobambusa quadrangularis
- Type: Running
- Average height: 10-25 ft (3-7 m)
- Average diameter: 1-1.5 in (2.5-3.4 cm)
- Hardiness: 10°F (-12°C)
- USDA zones: 8-10
- Light requirements: Partial shade
- Best use: Privacy screening, crafting, ornamental
Native to China, Japan, Vietnam, and the Himalayas, Square Bamboo has been successfully cultivated and grown worldwide in cool, humid conditions. For example, Square Stem Bamboo is a particularly popular cultivar in Britain, thriving where other bamboos do not.
Square Bamboo belongs to the Chimonobambusa genus along with other unique bamboos such as Chimonobambusa tumidissinoda or Walking Stick Bamboo. The Latin name of Square Bamboo, quadrangularis, means four corners, a fitting name given its square-like culms.
Square Bamboo’s unique features, including its square culms, tall size, and dense growth pattern, make it a perfect choice for privacy screening or as an ornamental. In addition, the strong culms of Square Bamboo are often used to make furniture.
What does Chimonobambusa quadrangularis look like?
As the name suggests, Square Bamboo is made famous for its square-shaped culms. Unlike the round culms of most bamboos, the culms of Square Bamboo have flat sides and rounded corners!
But the square culms of Chimonobambusa quadrangularis are not the only distinguishing feature of this bamboo. It has swollen, pronounced nodes that are striking and easy to spot at a distance.
In addition, the lush foliage cascades down, creating a waterfall effect. The long, pointed leaves are dark green when in the shade, or light green to yellow when exposed to bright sunlight.
Under ideal conditions, the culms of Chimonobambusa quadrangularis can grow up to 25 feet tall. They are also very sturdy and will grow up to an inch and a half in diameter when mature.
What are the best growing conditions for Chimonobambusa quadrangularis?
If you plant your Chimonobambusa quadrangularis in a location with the right conditions, it can be a very vigorous grower. You’re best off avoiding full harsh summer sunlight and picking a location with dappled sunlight and partial shade. While they grow and spread quickly, they are less likely to become invasive than other running bamboo varieties.
Like many other bamboos, Chimonobambusa quadrangularis only flowers sporadically. While it’s currently unclear when this species is most likely to flower next, it’s likely to be many years from now. As with other bamboos, the plant will die after flowering.
Light requirements
Square Bamboo doesn’t require ample sunlight to grow vigorously and beautifully. In fact, bright indirect light or partial shade will result in greener and more vibrant leaves than full sunlight.
However, Chimonobambusa quadrangularis isn’t tolerant of hot, dry conditions. Lapses in watering or scorching-hot summers can cause your bamboo to dry out or burn. You can avoid this by watering regularly and planting your bamboo in a partly shady spot.
Soil requirements
Chimonobambusa quadrangularis prefers moist (not soggy) soil and is not drought tolerant. Loamy soil is ideal for Square Bamboo, though it will tolerate slightly sandy or clay-like soil as well. It isn’t picky when it comes to soil acidity and pH and will survive just fine in either alkaline or acidic soil.
Fertilizing
You may not need to fertilize your Square Bamboo too often if you have high-quality soil with plenty of organic matter. But because they are vigorous growers, it’s good to fertilize periodically.
Juvenile Chimonobambusa quadrangularis prefer a fertilizer with more phosphorus to help them establish healthy root growth. In more established plants, a good way to check what type of fertilizer your bamboo will need is with a soil test kit. Then you can choose a fertilizer with an N-P-K ratio that best replenishes your soil.
A balanced all-purpose fertilizer will also work if you don’t want to test your soil. Fertilize early in the growing season, and follow the specific directions recommended on your fertilizer’s label to avoid over-fertilizing.
How to care for Chimonobambusa quadrangularis
Unlike some other species of running bamboo, Chimonobambusa quadrangularis is less likely to spread in such a way that it becomes invasive. With that said, you may want to use root barriers if you are concerned about your bamboo spreading beyond your garden.
Square Bamboo can also grow well in containers if you choose one large and sturdy enough not to topple over as the bamboo grows taller. This is a great option if you want to try growing it inside, either year-round or over the winter.
Watering
Square Bamboo needs to have consistently moist soil. It’s not drought tolerant and will grow poorly if you water infrequently, especially if you live in a naturally drier climate. This is certainly a type of bamboo that you’ll want to mulch to help lock in moisture.
Pay extra attention to your Square Bamboo if you have a dry spell or stretches of unusual heat. Give your Chimonobambusa quadrangularis consistent moisture to maintain its beautiful foliage.
As a rule of thumb, water Chimonobambusa quadrangularis when the top two inches of soil feel dry.
Pruning
Since Chimonobambusa quadrangularis is a running bamboo, it can take over your space if you aren’t careful. Pruning and thinning are effective methods of control when the bamboo is in a juvenile stage. For established plants, root pruning or root barriers are great ways to prevent Square Bamboo from becoming invasive.
Other than that, additional pruning isn’t necessary for your Square Bamboo unless you prefer to thin it for aesthetic purposes. For instance, some people will cut the tops off to create an umbrella-like effect with the foliage.
Common problems and pests
No bamboo is 100% immune to pests and diseases. Fortunately, Square Bamboo is highly pest-tolerant and resistant to many diseases. Still, make sure to look out for some common pests and diseases, including slugs and snails. Occasionally, you may find aphids or thrips on your Square Bamboo, but those can be treated with neem oil or insecticidal soap.
Ultimately, if you can maintain consistent soil moisture and provide plenty of nutrients, you are unlikely to run into much trouble with your Chimonobambusa quadrangularis.
How to use Chimonobambusa quadrangularis
Chimonobambusa quadrangularis is a gorgeous variety of bamboo. While it makes for a stunning ornamental, it’s also great for privacy screening due to its dense and lateral growth. Not only that, but it will make a statement if potted into an appropriate container.
Many people don’t know that Square Bamboo is also very sturdy and is often harvested for crafting and construction, particularly when it comes to furniture. Also, the new shoots and young stems are edible and can be cooked into a delicious dish!
