Bamboo is undoubtedly one of my favourite plants. I almost always use it in gardens I create.
Bamboo has striking presence. It can be used as a specimen plant – a star in the border, like this phyllostachys nigra – or as a wonderful screen.
Learning how to grow bamboo is pretty straightforward. I’ll take you through the important points in this article.
What is bamboo?
Bamboo belongs to the grass family (Poaceae). Species of Bamboo are native to most continents, except Europe. Most of today’s cultivated species originate from China, Japan or South and Central America.
Many of these species hail from mountainous regions or lowland plains of Asia where, in both cases, winter temperatures can drop as low as -25 to -30 degree Celsius (-15 to -20 degrees Fahrenheit). The consequent hardiness of these bamboos makes them ideal plants for the temperate regions of Europe and North America.
In addition, there are a number of tropical species of bamboo which originate from Africa, Australia and tropical parts of Asia. These require frost free conditions to survive in home gardens, but they are often amongst the most spectacular specimens you will find.
What are the main different types of bamboo?
The principal distinction among different types of bamboo relates to the plants’ root systems.
This is really important for home gardeners, because it can make the difference between selecting a species that suits your situation perfectly and one that takes over you garden (and your neighbour’s as well.)
Put simply, most bamboos either have a running root system (technically called a leptomorph system) or a clumping (or pachymorph) root system.
To explain the difference, it helps to understand some of the botany. Bamboo root systems comprise rhizomes and roots.
Botanically, rhizomes are underground stems. This means that like above ground stems they have nodes, which are the parts of the stem from which new shoots emerge.
In bamboo, the difference between running and clumping forms arises as a result of the size of the space between the nodes on the rhizome (the internodes).
Clumping forms have short internodes, which means that new culms are produced close to each other. Running forms have much longer internodes. The rhizome stretches out and may reach lengths equivalent to the height of an above ground culm, with new individual shoots growing up from any of the nodes along its length.
Whilst the tendency of each form to run or clump can be a bit variable according to the particular conditions a plant is grown in, this distinction is one that it will always pay to have in mind when selecting bamboo for your garden.
What growing conditions does Bamboo need?
The degree of sun or shade that an individual species requires or will tolerate, is always a function of that particular species. Likewise, a bamboo’s frost hardiness varies from species to species. You will therefore always need to check these factors in relation to any particular species you are interested in growing.
Nevertheless, there are some common features relating to bamboo growing conditions that should be mentioned here.
Firstly, it is worth noting that bamboos are tough plants and will tolerate a degree of neglect. Indeed, where space is an issue, their growth can be kept in check if they are fed sparingly after planting.
Related to this is the fact that bamboos can be planted in many different soil types. I recall no noticeable difference in the healthiness of two plants of the same species which I planted in two different parts of a garden where the soil type in each area was quite different – one was heavy clay, the other a nice open loam.
Interestingly, these were Phyllostachys bambusoides ‘Holochrysa’, which is a running species, and the specimen in the loam had a much greater tendency to run than the one in the clay. This seems to bear out the observation above about the impact of growing conditions on these characteristics.
Thirdly, whilst they need plentiful watering during the growing season (see below), bamboos will not generally tolerate poorly drained soil. So in heavy soils it is important to incorporate gravel, grit or other material to open up the soil so as to prevent waterlogging.
How to plant bamboo
When planting bamboo, you will need to have regard to the eventual diameter of the plant and locate it where its natural growth will not interfere with existing features, such as paths or boundaries.
You will also need to decide whether you want to install some kind of barrier to restrict the spread of the plant. As indicated, this will be necessary in most home gardens for running species. But it may even be necessary clumping species if space is at a premium.
Purpose-made bamboo root barriers, like the one below, can be installed. These are usually available from bamboo retailers. But it is also possible to make use of other impenetrable material, like offcuts of paving or hard plastics, set vertically around the edge of the planting hole. These should be placed so that at least 3 inches (75cm) of the material is above ground.
A simpler way to ensure that you can keep your plant in check is to surround it with a shallow trench. Bamboos are not deep-rooted and their rhizomes extend outwards just below the soil surface. If you surround the plant with a trench 9 to 12 inches deep (22 to 30 cm), you can simply prune off any extending rhizomes as they enter the trench.
One grower I have heard of fills the trench with sand and tops it off with a light mulch, so that it is invisible. She then simply inspects the trench at the end of each growing season and deals with any infiltrations.
Bamboo is best planted in spring, so that it has a long growing season to settle in and take root.
You’ll notice that most bamboos you buy from nurseries are quite heavily pot bound. You may even need to cut the pot off with a knife. Because of this, you should give the rootball a good soaking before planting, ideally immersing it in water for at least twenty minutes, so that the water can seep right into the interior of the rootball.
Dig a hole twice the width of the rootball and one and half times the depth (I know this is not always possible, but do the best you can). Add drainage material if necessary and, if you want your plant to grow away well, add some manure, humus and organic fertiliser to the bottom of the planting hole and mix this in with the back fill.
In dry areas the plant can be set in a small depression. In areas of high rainfall, the plant can be slightly mounded.
Once planted, water in well and mulch with compost, well rotted manure or leaf mould.
How to maintain bamboo
Maintaining bamboo is not especially difficult, which is another great reason for using these magnificent plants.
Food and water
For the first two years, make sure that your plant is well watered. This is essential.
Bamboos can be greedy feeders, but they can also thrive quite happily with one decent feed in spring with an all purpose organic fertiliser. In essence, the more you feed a bamboo plant, the more it will grow. This is why you can limit its growth by limiting its nutrient intake.
Be aware that bamboos are intolerant of salt and therefore may react badly to seaweed based fertilisers.
Make sure that the area around your plant is always well mulched. This helps retain moisture and maintains an even temperature around the roots of the plant.
You’ll notice that the plant builds up its own mulch of leaf litter and shed culm sheaths in time. But you will do nothing but good to the plant if you add to this with organic mulches, like bark, wood chips and leaf mould.
The best way to keep you plant looking strong and healthy is to prune it to remove weak, damaged or old culms. Old culms can be identified because the are usually a dull colour. Cut the these culms at their base. The effect of this is to open up the plant, allowing more air and light into its center, which helps maintain the plant’s overall health.
You can also ease congestion of your mature plants by pruning off some of the side branches that emerge from the nodes of the culm.
A striking effect is obtained by removing all branches at low levels, enabling the beauty of the plant’s culms to be fully appreciated.
If you have culms that are leaning over significantly, you can sometimes right them by pruning a few nodes from the top and/or by pruning the main branches near the top of the culm on the side towards which it is leaning.