Bamboo, a plant with mysterious secrets

Light shining through bamboo plants

It’s very difficult to classify these gigantic stalks: they’re the size of shrubs and grow like perennials… but they’re technically grasses! Some bamboo plants are towering high, others are dwarf-sized, some have straight canes and others arch back down and even creep along the ground.

Very easy to grow – sometimes too much so! Nonetheless, they still win over the hearts of many thanks to the many shapes and forms bamboo takes on.

1- A mysterious plant

The word itself – “bamboo” – comes from the Malaysian language. It describes grasses that has woody, long lasting stalks. These typically last for years, some species even keep their stalks for a decade.

Hollow canes with a blazingly fast growth incorporate a curious mineral: silicon in their structure. It confers a powerful strength to its wood. Bamboo uses span from building materials to scaffolding and cooking utensils… and of course, garden uses!

Bamboo flowering and blooming
Blooming on a bamboo is impressive

The blooming itself is a mystery: it seems to respond to an internal clock that each species follows. A given species will bloom throughout the entire planet at the same exact moment, and it’s completely unpredictable and isn’t related to the season! After blooming, bamboo stalks pour all their energy into making seeds, and quickly thereafter die off. Sometimes a clump can be saved by giving it lots of nitrogen fertilizer, or of course by cutting the flowers off.

2- Why is bamboo so invasive?

Soil, heat, species

The clump sends rhizomes out. These are underground stems, technically, with roots, buds and scales (which are modified leaves), capable of burrowing near or far and, after a distance, break through the surface. How far the clump spreads depends on the species, but more than anything the soil type and climate are major factors.

  • In heavy, cool soil, bamboo will spread much less than in sandy soil. Sandy soil is easy to wind through, and it warms up faster in good weather.
  • It’s the same thing with temperature. Growth, both horizontally and in height, are much less vigorous in northern, colder climates than in southern, warmer ones.

How to avoid being overrun by bamboo?

There are a few easy tips to keep ahead of things:

  • Barrier against bamboo
    Make sure the rhizome barrier is at least 4 inches or 10 cm above ground level

    set up rhizome barriers all around the clump. Use 2½ foot (70cm) polypropylene rolls, stainless steel sheets, or a cement ring.

  • Another idea is to plant your bamboo on a small island surrounded by water, like a moat: this will also keep the bamboo from spreading.
  • Dig a trench or a lower-than-ground level walkway all round. It must be at least 6 inches wide and 1 foot deep (15 cm wide, 30 cm deep). Then, patrol the trench every week during the growing season and cut off any rhizomes that peek through. Don’t throw them out: they’re edible!
  • Plant bamboo in a deep container.

To learn more, read: Invasive bamboo, what are the options?

3- Choosing the right bamboo for a deck or terrace

Getting the hardiness right

Bamboo is a very appealing landscaping option for a deck. Average-sized species (5-6 feet or 1.5/2 meters) are perfect to create a privacy hedge that will also block sound out: you’ll be savoring a tropical atmosphere!

Many species are perfectly happy in pots, the so-called dwarf species, especially Fargesia which are known for their tight clumping habit , but others are just as suitable! Check the level of hardiness on this chart, you’ll discover which bamboo species are better for mild climates or even indoor growing. Next to consider is the shape and elegance of the foliage, with shades of green, gray and gold. Bearing and habit, how the clump grows, and the form and color of canes. Some cultivars have a truly surprising appearance.

Our favorite bamboo

Chimonobambusa tumidissinoda:

  • Chimonobambusa has large nodes
    Chimonobambusa tumidissinoda with swollen nodes

    It’s very ornamental, with wide nodes that led to its nickname, the “trumpet bamboo”.
    Its narrow leaves and elegant bearing make it perfect for decorating a terrace, garden and even indoors.
    Its culms are also favored in cooking. However, in the garden, watch out: it spreads quickly!

Phyllostachys nigra:

  • The black canes of this one are famous throughout the world, but few know they only turn dark after 2 years.

Shibatae kumasasa:

Shibataea kumasaca is a type of bamboo that stays small and is for topiary
Shibataea kumasaca stays small and lush, great for topiary

Dwarf bamboo such as Shibatae kumasasa will form a thick ground ground cover, 2 to 3 feet thick (50 to 100 cm), a moderately running variety, has wide leaves. Leaf tips turn silvery-gray in winter.

You can trim it as much as you want to shape topiary, or simply cut the stems back every 3-4 years.

Semiarundinaria fastuosa:

This variety is interesting for growing in containers: the columnar shape of its tall stems (15 to 25 feet or 5-8 meters) and slow-spreading rhizomes make it appealing for that use.

Semiarundinaria fastuosa has white sheaths that protect young shoots
Semiarundinaria fastuosa with long ornamental leaf sheaths.

Its green canes take on a beautiful purple-brown color in the sun, and the dense leaves are surrounded with long, light-colored sheaths.

It’s as happy in the shade as it is in full sun, and young shoots are also edible.

Phyllostachys aurea ‘Flavescens Inversa’:

has green, yellow-striped canes, and ‘Holochrysa’ has copper and bronze-like colors. Both are vulnerable to wind when the temperature hits 14°F (-10°C).

Even though they’re very hardy (-4°F or -20°C), we recommend growing it in a container on a covered deck or indoors because the rhizomes are very invasive.

4- Not much to worry about

Bamboo needs a lot of water, especially when they’re not given much space for their root clump, but they generally don’t like permanently soggy soil. They love full sun and part shade, and soil that isn’t too compacted.

In garden boxes, add slow-release fertilizer upon planting, and then top it off with regular, nitrogen-rich lawn fertilizer.

Directly in the ground, you won’t even need to provide that. Once the clump has settled in, dried leaves falling down from the canes and breaking down will provide the plant with enough matter for new shoots to appear (it especially replenishes silicon).

Eva Deuffic

To learn more, read:


Image credits (edits Gaspard Lorthiois):
CC BY 2.0: Joi Ito
Public Domain: Daderot, Batholith, Bat
Pixabay: Sookyung An
Nature & Garden contributor: Eva Deuffic