How does bamboo grow?

Some of us have been fortunate enough to visit places like Asia, South America or Africa and marvelled at the sheer presence of giant Bamboos. That once established, those monster poles (culms) reach full height in just a couple of months is astounding. Here in Tasmania, we can only dream of such growth and are resigned to cultivating plants that will reach only a fraction of the 40 metres height of the worlds tallest Bamboos. The wonderful temperate climate we enjoy so much, simply can’t provide the growing conditions necessary for such proliferation. Let’s examine the incredible phenomenon that is Bamboo and how it actually grows. The following article is in part a reproduction to which my Tasmanian experiences have been added.

Running or Clumping

Not everyone is aware that essentially (but by no means exclusively), there are two types of Bamboo: Monopodial or Running Bamboo and Sympodial or Clumping Bamboo. Almost tragically, the runners are mostly suited to cold temperate zones having mainly originated in Northern China and Japan, some in Korea.

The Phyllostachys genus constitutes a large portion of cold climate runners and appears to be the most prolific of the Bamboos imported into Tasmania. Interestingly the extent of Monopodial Bamboos’ invasiveness into the landscape is dependent on soil and moisture conditions. So much so, that it is indeed possible for their rhizomes to not venture beyond a small area and appear to be non-invasive or clumping. Given good soil and water conditions however, the running rhizome can travel klms and become a formidable foe to in an unsuspecting neighbourhood. It is this half of the Bamboo world that has given the plant its notorious, quite deserved ‘invasive weed’ label. Its invasiveness is due to the underground rhizome growing laterally and extending into bud forming nodes, each of which form a new rhizome or shoot which leads to a massive proliferation after some years of sub-surface gamboling.

Sympodial (clumping) Bamboo has suffered in reputation due to its colleague’s errant behaviour to the point where the ‘sympodial ignorant’ refuse to believe its ‘non-invasiveness’! Intrinsically, the major feature that distinguishes Sympodial Bamboo from the monopodial, is that each rhizome produces only one other rhizome, which grows vertically, to become a shoot/culm, nestling close to its mother for life. This ‘living with the relos’ attribute results in a defined footprint which delivers its non-invasive characteristic.

What follows, is true in the main for both Monopodial and Sympodial Bamboo – where there are differences, they will be highlighted.

How fast does Bamboo grow?

• Bamboo forms new shoots (culms) in spring. In Tassie this can vary and we may not see new shoots until late summer. If we’re really lucky – both. These shoots rise from the ground and grow in height and diameter for about 60 days. During these 60 days, it forms limbs and leaves. Late shoots will generally NOT reveal leaves & branches until the following Spring.
• Bamboo does not experience secondary growth like trees or most plants. It sprouts new leaves every year, and a Bamboo culm usually lives for ten years. After the 60-day growth period, the Bamboo does not continue to grow in height or diameter.
• Bamboo belongs to the grass family. It is a colony plant, which means it uses the energy of the existing plant to produce more plants and expand the root structure. The new plants grow in the same way. Within 60 days, new shoots emerge and develop into a stick with limbs and leaves.
• Bamboo takes about three years to establish itself. Once established, the new shoots that sprout in spring/late summer (they still only grow for 60 days) become larger and more numerous each year as the colony grows to maturity. Different species need a different number of years (4-15) to reach their maximum size. This depends on the choice of species, soil, sunlight, climate, and water conditions.

This may seem lengthy, but it is necessary and exciting to understand your new Bamboo. Every year customers turn to us because their Bamboo is just standing there and not thriving yet in a different part of the state or even town, others are bursting skyward.

Bamboo grows differently than most other plants. It is not for nothing that it has the title “the fastest growing woody plant in the world“! It’s hard to understand what’s happening.

How to start growing Bamboo

Use a plant and not seeds! Temperate Bamboo usually sows in 75-year cycles, and seed viability is very short. If true seeds can be sourced, they are usually not viable and unwise use of time and money.

It is essential to know that the Bamboo-section you start will only grow underground. The culms attached to the rhizomes or roots have finished growing and only support the rhizome system. So don’t expect the culm to take off and grow bigger or taller.

Each shooting season, the new culm grows to the diameter it will one day have, and in a few months, grows to the height it will one day have. The growth of the entire life cycle of the cane will be completed in just a few months.

Bamboo growth cycle

• Initial Bamboo never grows back in height or diameter.
• New shoots appear in spring and can grow up to one meter per day. Dreaming in Tassie!
• The new growth cycle usually lasts 60 days.
• After this 60-day growth period, the Bamboo canes never grow again.
• The Bamboo grove (running Bamboo) stand (clumping Bamboo) uses the energy of the existing culms to produce more prominent and more numerous shoots in the new season.
• The Bamboo grove/stand produces larger culms until it reaches maturity, usually 7-10 years after planting.

The size of the initial planting, the species, the age of the grove/stand and the environment are all factors that influence the size of the new shoots. Your starter plant should be a healthy offshoot from an established Bamboo grove/clump.

The Bamboo you start with should not be considered a single plant but become a colony.

This colony is underground primarily (50 % of the mass). The culms or canes supply the underground rhizome colony with nutrients. When the time is right – newly formed rhizomes become shoots and shoots become culms as they telescope from the ground up.

The increase in rhizome growth allows the Bamboo to store nutrients and thus produce larger plants until a mature culm size is reached throughout the grove/stand.

A baby girl and a baby boy may have some similar characteristics to their parents, but they do not look like them early. As the baby matures, it becomes more like the parents. The same is true for your new Bamboo section.

The culms or shoots and leaves will most likely not have all the characteristics of the adult Bamboo, such as stripes or leaf size. Remember that, like a newborn baby, it may take some time before all the Bamboo features are formed. Because of this delay, it is advisable to buy Bamboo from a reputable source.

New growth

In season, new culms sprout upwards from the rhizome nodes. These new shoots are very tender and can break at the slightest shock. The culms rise from the ground with the diameter they will always have and grow at a fantastic speed for 40 to 60 days.

In Tasmania this will only be the case with Spring shooting, late Summer/Autumn shoots may perish if they haven’t grown sufficiently to sustain life through Winter. Those late shoots that do survive the frosts/snow should resume their growth with the onset of warmer weather. Effectively, the late shoots therefore, can grow over two seasons.

When the new shoot reaches its height, it unfolds its branches and new leaves even though the culm does not increase in diameter or height for the rest of its life.

Best soil conditions

Bamboo is not fussy about soil conditions, but optimum soil conditions are pH 7 or neutral, sandy loam with high organic content. Like most plants, Bamboo does better with a good layer of organic matter and loose soil that allows good drainage. However, Bamboo also does well in loamy and less favorable soils.

Bamboo roots are not deep and get most of their nutrients from the first 12 centimeters of soil. Bamboo does not grow in standing water. The soil must be able to drain.

The root system can deteriorate if submerged in water for weeks. Bamboo must not be confused with “lucky Bamboo,” which is technically a lily and can grow in water.

Sunlight conditions

The more sunlight, the more energy is available for photosynthesis and growth. Most Bamboo species need at least 4 hours of filtered sunlight or more to be planted successfully.

A smaller group of species with larger leaves and more miniature canes, 20 feet or less, prefer partial shade growing conditions, but this is not the norm for Bamboo.

Fertilize to encourage growth

Fertilizing can increase growth by a year or more. Fertilizing is the very best way to increase growth! Bamboo can benefit from the additional energy provided by additional Fertilization, and not all soils are the same. Because of Bamboo‘s frequent soil deficiencies and urge to grow, we recommend using a balanced slow-release fertilizer.

A slow-release fertilizer reduces leaching and provides nutrients in a time frame that matches the Bamboo‘s ability to absorb the nutrients. Fertilization can help accelerate growth and significantly reduce the Bamboo‘s time to form a screen or reach a mature size.

In three to five years, under good growing conditions, a single Bamboo should have 20 to 40 culms and have reached near full maturity. Of course, this depends on the species chosen, and some species can reach a diameter of over 3 inches and a height of 30 feet in just seven years – even here in Tassie.

What to expect from the Bamboo grove?

In the case of Monopodial (running) Bamboo, it takes about three full years for the mother plants to take off in the ground and form several shoots that make a Bamboo grove.

Here are the typical results under normal growing conditions for Sympodial (running) Bamboo: From a 200mm pot (1-2 culms), you should have a few new shoots the first growing season.

The following season, these culms may then produce a few more each. In the third year, the increasing growth will become apparent when all these culms produce more growth.

After about three full years, it becomes pretty impressive because the new culms (canes) that sprout each spring are more significant and taller than last year’s growth.

First 3 years of Bamboo growth

1. Sleeps
2. Creeps
3. Leaps

The mother plant (whatever size you start with) is finished in diameter and height, but the rhizome will grow underground.

Bamboo is a (grass) colony plant, and most of the Bamboo grove/stand will be underground. Each season, the new culms will start to grow taller in height and diameter than the previous season’s growth, until after a few years, the mature size of this species is reached.

As a Bamboo grove/stand develops, the new culms (poles) become more significant in diameter, and the height of each NEW culm increases until the grove reaches maturity. The oldest culms are usually the smallest.

The new culms that grow in the spring/late summer of each year usually become taller than those of the previous year. This is due to the enlargement of the underground system of rhizomes or roots.

Controlling the Running Bamboo

In temperate latitudes, the most prolific growers (sadly) are runners which usually sow in a 75-year cycle with small seed production. Propagating Bamboo by seed is very difficult. The primary propagation mechanism is the spreading of the roots (rhizomes) and the production of new culms. The rhizomes of the running Bamboo track laterally underground.

If you control the roots, you also control the Bamboo. You can prune the roots twice a year, or Bamboo Shield is a good option. Bamboo Shield offers an ‘almost’ worry-free way to contain Bamboo.

With Bamboo Shield, you can define the area where you want the Bamboo to grow. You can use it to create long privacy screens or even unique patterns in the ground. Installation is simple, provided you can dig around the ground. HINT: Ensure you install more and deeper than recommended.

A trench is dug around the desired area, and the Bamboo Shield is installed vertically to prevent the Bamboo roots (rhizomes) from spreading. Bamboo has neither a stake nor deep vertical roots. It has a simple root system that runs parallel to the ground, usually in the first 14″ of topsoil.

You can also cut off any unwanted new shoots to prevent the Bamboo from spreading. This needs to be done carefully but is a suitable containment method if you have access to the areas where the Bamboo is shooting. New shoots are fragile when they first appear and can easily be mown or cut with a string trimmer/brushcutter.

Bamboo Anatomy

Bamboo belongs to the monocotyledonous plants as it has hollow stems with scattered vascular bundles and leaves with parallel veins. The woody, ring-shaped, vertical stems are called culms or are commonly called canes. As previously stated, the most common Bamboo species in temperate zones belong to the genus Phyllostachys.

They have a furrow or sulcus above each branch base with two alternate limbs at each nodal ring. This is the species most people think of when they think of Bamboo. However, there are many species with different characteristics.

Some species have a colored furrow or sulcus. The internodes can be green and have a yellow stripe in the furrow. Others have yellow rods with green stripes in the furrow.

Others are green with black coloring, intensely black, spotted with wine-red or purple. Many species have three or more limbs at each node. Can continue the list of different Bamboo species indefinitely. This does not even take into account the different colors of the leaves and their variegation.

Bamboo is evergreen and produces new leaves every year. This new leaf growth takes place in spring. This procedure is gradual and is highlighted by a new carpet of golden brown leaves in the grove. The changing of old leaves to new in particular in immature plants can look particularly nasty, as if the plant is dying. The irony with young, potted Bamboo is that when gardeners are seeking them in the Spring, they generally look their worst as this process takes place.

It is essential not to remove this carpet of leaves from the groves as it provides mulch and nutrients for the colony. Since Bamboo is an evergreen tree, it can serve as a screen at all times of the year.

Cold weather hurting Bamboo

Many Bamboo species survive even when exposed to lower temperatures than those advertised. While it may be painful to see your beautiful foliage or culms die due to extreme cold or wind chill, in most cases, it is reassuring to see the Bamboo re-bloom the following spring with new culms and often new foliage on seemingly dead culms.

Again, this generally happens if the Bamboo has been exposed to temperatures below those recommended for the species or extreme cold.

It is always essential to choose an appropriate species for your climate zone and application.

We have tried to grow many tropical species here in Tasmania – most have perished with the first frost with only a few survivors. There is however, a BIG difference between surviving and thriving!

Pots and planters do not provide the same insulation as the soil. If you are using a planter or container, choosing a colder resistant species is essential than that generally required for in-ground planting.

How long does Bamboo last?

A Bamboo grove/stand can last a hundred years or more. An average Bamboo cane can live up to 15 years, depending on the species, but generally, 7 to 10 years is the rule. With runners – the initial and smaller plants die a little faster as the grove matures because of a lack of sunlight.

The good news is that after a few years, when the starter plant starts to die back, you are well on your way to having a grove/stand or canopy of mature culms every spring and summer.

Bamboo applications

 Bamboo can green your garden in winter, and it can stabilize the soil of slopes and combat the worst erosion problems.

This plant can act as a screen or windbreak and can be pruned to the height you require. We carry Bamboo species for almost any application with various sizes, colors, and winter hardiness.

We primary sell Bamboo for:

• Privacy Screens
• Ornamental
• Accent plantings
• Bamboo craft/construction
• Biomass applications

Please let us know if we can help you choose or supply you with one of our beautiful Bamboos.

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