Inner wisdom

In addition to being a giant grass associated with tropical climates and the Far East, bamboo is famously hard and hollow. Its hollowness helps make the bamboo lightweight and flexible. You will also find that bamboo is much easier to saw through, compared to solid wood.

Is every bamboo hollow?

Hollowness is the general rule with bamboo, but there are exceptions to the rule. Among the 2000 kinds of bamboo in the world, the vast majority are hollow. But some canes have thicker walls than others, and a few of them even grow solid.

When we talk about wall thickness, this is not the same as the diameter. The diameter describes the girth of the poles. Bamboos can vary from less than a half inch in diameter to more than five inches in diameter. But the wall thickness refers to how much woodiness there is between the inside and the outside of the ring. Usually it’s just a centimeter or less, and the center is hollow.

All different varieties of bamboo have different wall thickness, and this is a very important quality to consider if you plan to use the bamboo for construction. Bamboo with thin walls will bend more easily, which might make for better fishing poles. On the other hand, thicker bamboo will be stronger, sturdier and better for building substantial structures.

Bamboo in the node

Sometimes you’ll see a cross-section of bamboo that is solid. But in most cases, this is not from a bamboo that is completely solid. More likely, it was cut at the node where the bamboo is solid. The spaces in between, the internodes, are probably still hollow.

This is another feature that makes bamboo fun to work with. Cut a thick bamboo pole just below the node and some inches above the node, and you’ll have a simple yet attractive drinking cup. Keep in mind, the bamboo is not entirely water proof, so it shouldn’t be used to make a vase for flowers. It’s perfect, however, for something like a pencil holder.

If you do want to make a bamboo vase, the best method is to use a very thick diameter bamboo culm, and slip a narrow glass inside. The glass won’t be visible from the outside, but it will hold the water. Otherwise, the bamboo will gradually soak up the water, eventually leaking and making a big mess.

Solid bamboo varieties

One of the few varieties with a solid stalk is Phyllostachys heteroclada f. solida. Commonly known as simply “solid bamboo”, this is a subspecies of “water bamboo”, thriving in swampy areas and river beds of central Asia.

Dendrocalamus strictus, a timber bamboo native Southeast Asia, also has the nickname of solid bamboo, and for the same reason. This could be somewhat confusing, except that these varieties have very different habitats and growth habits. Phyllostachys is a genus of temperate runners, and Dendrocalamus bamboos are tropical clumpers. In most cases, D. strictus has very thick walls, but is not completely solid.

Dendrocalamus stocksii grows in northern India and has completely solid canes. This species is also interesting for the fact that its flowers never actually go to seed.

In Central and South America, most members of the Genus Chusquea have solid stems. The most popular species for ornamental cultivation are probably C. gigantea and C. culeou, both native to Chile. Attractive culms and lush foliage make them nice to look at, and the solid poles are excellent for crafts and light construction. Another interesting species, C. quila tends to spread out and grow like a vine. They appear predominantly in Chile and Argentina.

Indocalamus latifolius ‘Solidus’: This unusual species not only has solid stems, but it also has exceedingly large and leaves with prolific foliage. This makes it a great choice as a low privacy hedge. They usually grow 8 to 10 feet tall, or less in cooler climates. Thin, graceful culms are about .5 inches in diameter and turn a lovely deep, dark green with age. This running bamboo is also very cold tolerant, hardy to -5º F.

Further reading

To learn more about other bamboo varieties and growth habits, take a look at some of these interesting articles.

PHOT CREDIT: Takeo Kunishima (Unsplash)

Hollow bamboo pin