Can You Tell The Age Of A Bamboo Stalk?

With most trees, you can measure the circumference of the trunk or count the number of rings to determine its age. Because bamboo is a grass, not a tree, tracking and identifying the bamboo age by its stalk can be tricky.

Bamboo stalks grow the most during the first year, reaching their full size early on in life and gradually maturing over the next few years. While it’s hard to know the exact age of bamboo stalks, there are a few ways to estimate their general age and maturity. The key to determining the age of your bamboo is to inspect the stalks themselves.

Knowing the age of your bamboo stalks is a good practice for any bamboo gardener. But it’s especially important if you’re planning to harvest your bamboo for crafts or construction projects, as culms are useful for different things at different ages. Read on to learn how to tell the age of a bamboo stalk!

Why is it important to know the age of a bamboo stalk?

There are many benefits to knowing the age of bamboo before you harvest it, as bamboo stalks have different uses at varying stages of maturity. For example, a young culm is great for crafts and basketry, but still lacks the structural integrity of a more mature culm, which can be used in construction.

One of the most rewarding aspects of growing bamboo is that it grows quickly and lives a very long time.

Bamboo can grow to its full height within its first year, but the stalks can take several years to strengthen and mature. Therefore, it’s not the size of the bamboo but rather its age that determines its strength.

As bamboo matures, the stalks become stronger and can be used for construction and building materials. But old bamboo stalks aren’t necessarily what you want. Past a certain point, they become dry and brittle and are best left alone. 

This chart gives an idea of when the bamboo age can be utilized for different projects:

Can You Tell The Age of Bamboo Stalk?

While it might seem like it, bamboo is not a true wood. But while you can’t count rings to tell the age of a bamboo stalk, there are two ways to figure out the age of your bamboo. You can track the age or inspect the plant.

How to track the age of a bamboo stalk

Tracking the age of a bamboo plant mainly makes sense if you want to follow the life cycle of specific shoots. There are two methods commonly used to achieve this:

Plant a stake

The first method to track your homegrown bamboo’s age is to plant a stake in the ground next to it. You can mark this stake with the date the bamboo emerged from the soil. Or, if you transplanted the bamboo, you can use the date it was planted.

One drawback to this method is that stakes can easily uproot during inclement weather, so make sure that your stake is deep enough to endure its environment. This method is best used for running bamboo, as it can be difficult to keep track of stakes in a tight clump of bamboo stalks.

Mark the stalks

Another way to keep track of your bamboo’s age is to mark the bamboo stalks directly in the year they emerge from the soil. You can either mark the culm with the date or color code your bamboo to indicate the year they have been planted.

This method is especially beneficial if you grow plenty of bamboo clusters and tend to lose track of their age. While this is a very efficient method to tell the age of your bamboo stalk, it’s important to consider whether marking it will affect harvesting it later on. 

Also, consider using a non-toxic paint or material so this method doesn’t negatively impact your bamboo stalk or soil.

Inspecting bamboo stalks to estimate their age

If you find yourself staring at your bamboo, wondering how old a particular bamboo stalk may be, you can estimate its age by simply inspecting it for signs of age. While this method is not as exact as marking by year, inspecting the culms closely can help you narrow down the growth stages.

There are typically five stages of growth in a bamboo’s life cycle:

1. Stage: Bamboo less than 1 year old

It’s easiest to tell the age of a bamboo stalk when it’s still in its juvenile stage. A new shoot, just days or weeks old, will be completely enveloped in a paper-like sheath. It may resemble a new leaf or growth point on a common houseplant in its early stages.

Growers often harvest these young bamboo shoots for culinary purposes while the bamboo is still tender. However, before you start to munch on your bamboo stalks, it’s important to accurately identify the type of bamboo that you are growing to ensure that it is edible.

Bamboo will quickly pass this stage and start to grow taller. It will typically reach its mature height between 6-9 months! However, it will take several years for that stalk to completely mature once it has grown. Bamboo at this stage will typically be bright green and unblemished.

2. Stage: Bamboo stalks between 1-2 years old

Bamboo around 1 year old will still have a vibrant green color. The paper-like sheath wrapped around the stalk may start peeling and falling off in certain places. No lichen will have formed on the bamboo yet.

Overall, these young culms look fresh and new, with minimal branching. Bamboo at this age will develop rhizomes, which act as roots. From this rhizome, more offshoots will develop. Many people recommend holding off harvesting bamboo until it has reached full growth for the rhizomes to fully develop to create more shoots.

3. Stage: Bamboo stalks between 2-3 years old

After a few years, bamboo will start to develop white, green, or rust-colored spots, known as lichen. Lichen is a fungus that grows on trees and bamboo stalks. It’s primarily drawn to clean air and is often used to indicate air purity.

Unlike other fungal diseases like black sooty mold, lichen is quite common on various bamboo stalks, and isn’t harmful to the bamboo. On the contrary, it can even be beneficial.

Lichen will absorb nitrogen from the air, seeping into the soil when it rains, allowing the bamboo to absorb the excess nitrogen. Nitrogen is a key macronutrient to stimulate leaf and foliage growth and is very common in store-bought fertilizers, so in a way, it’s a natural fertilizer! 

In this stage of your bamboo stalk’s life cycle, the lichen will only just start to appear on the culm. They will not be fully formed with texture. This will tell you that the bamboo is more mature and established but not quite fully mature.

4. Stage: Bamboo stalks between 4-6 years old

When your bamboo culm has reached 4-6 years in age, that lichen will be much more visible.

At this stage, moss will also begin to grow on the bamboo stalk. Moss typically will start to appear around the nodes of the stalks.

The stalks themselves will also begin to lose their vibrancy and green coloring.

While you may think this means the bamboo is no longer useful, this type of bamboo is excellent for construction. There is much more happening inside the bamboo culm at this stage as it grows stronger.

Bamboo stalks between 4-6 years have grown very thick, making them very durable and sturdy.

5. Stage: Bamboo stalks over 6 years old

Bamboo stalks over age 6 become increasingly more challenging to identify, especially without cutting them. After 6 years, the bamboo will gradually lose its strength.

At this stage, you may find the development of small holes in the culm from insects. While your older bamboo stalk can still be harvested and used, you will likely have to inspect it once harvested to determine if it is strong enough for your needs.

How do you keep track of the age of your bamboo? Let us know in the comments!