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| B oldhamii - Planted in a 900mm wide raised
garden bed in a suburban garden as a privacy screen |
Clumping bamboos make ideal low maintenance hedges. The species should be chosen according to height requirements, sound barrier specification, and/or ground or air space requirements.
Vertical clumping bamboos take up less air space, and have less tendency to hang over the next door fence. Bushy species with large pendulous diameters have a denser sound damping effect but create less height and take up more ground space. You can achieve both height and density by choosing to plant more than one row of different species.
Some selected species have thorns capable of acting as a security fence, or even a cattle hedge.
Most clumping species properly selected for the site need no maintenance other than fertiliser and water. Most species, particularly the smaller ones, can be trimmed or even topiarised into the shape and height you want. Properly selected clumping bamboos do not need planting in pots or retaining boxes, and can be shape or size modified with very little effort to achieve the desired form (by removing soft new shoots or trimming culms).
For details of this, colour photos, and a wealth of other information, see the book "Bamboo World".
To achieve a hedge effect with clumping bamboos, you will need to plant a row of evenly spaced plants at equal centres, because each plant stays where you plant it. The number of plants needed depends on the size and natural diameter of the species selected, with each plant near enough to touch the next. Spacings vary between 1 metre to 5 metres depending on species shape and size.
If a tall bamboo hedge is required, remember that it will be bonsai’d if the roots can’t feed freely around the plant, including into the adjacent property as with any plant near a boundary. In such cases the plant will still look attractive but will not reach the potential height for that species.
As an example, one client wanted a tall vertical hedge about 12 metres high with concrete paved areas providing only a 90mm strip of soil available for the hedge. B oldhamii was planted at 1.4 metre centres, and grew rapidly to the required height, and is showing no signs of exceeding that height (the tips could be cut off new shoots if it did, but it doesn’t). That species is capable of reaching 18 metres high in ideal conditions with unencumbered root access, and would normally be planted 2.5 to 3 metres apart for a hedge.
In Asia, box hedges are created by trimming new culms to the desired height before they shoot leaf.
Running bamboos (monopodial) will send out rhizomes like long underground canes in all directions including under the fence into next door, and they will send up shoots many metres away where they are not wanted. Runners cannot be properly controlled by removing new shoots. Their object is to create a forest, and the rhizome build-up of runners is such that eventually they clog and deplete the soil even in areas where shoots are cut off each year. The plant eventually becomes shabby and undernourished (this also happens when they are planted in a garden box designed to retain them).
Clumping bamboos are not only easy to control, but they reach full potential size in half the time it takes for runners, because they invest their time in above ground growth rather than below ground growth. Clumpers have very short rhizomes that remain close to the clump, and the fine roots that radiate out around them are not invasive, and cannot create new plants. We do not sell running (monopodial) bamboo species because of their invasive habit, and because there are many clumping bamboos that will do the same job.
When planting a clumper close to your neighbour, allow enough room for the development of the clump’s rhizome circle over the years, which is very little (less than 1 metre diameter) for many smaller species, and not much more for some larger species; otherwise eventually some shoots may appear close to the fence in your neighbour’s yard. If you want to plant a non invasive clumper closer to the fence, you can plant a shallow strip of heavy fibro board against the fence (say 250mm for most species, or a little more for larger species). The rhizomes can’t travel in that direction because they are very shallow and are not adventurous in looking for new feeding grounds like a runner. The harmless fine roots (which cannot create new plants) will travel under the fibro board and feed in a complete circle around the bamboo. Between a brick wall and a fence, you may choose to lay the board against the fence base, fill the gap between the board and the brick wall with soil, and plant the bamboo in the above ground soil (saves burying the board!).
Remember that your bamboo hedge will probably reach 75% of its potential height within 2 years, and 100 % within 4 or 5 year, so hedges happen quicker with clumping bamboo than with any other plant.
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