Popular variety Slender Weavers is screening out a three-storey building in just 18 monthsThe words "screening" and "hedging" are often used interchangeably, but they mean slightly different things.
Screening plants will break up a view, block it to some degree and reduce harsh sunlight. They will not provide dense block-out or a high level of privacy.Hedging plants are either naturally dense or pruned to be dense so that they provide near-total block-out of views and great privacy.
Different clumping bamboo varieties that can work as hedges or screening plants – and some offer the best of both worlds.
Understanding clumping bamboo
Many people are alarmed by any mention of bamboo – and not without reason. Running bamboos can be destructive and hard to control, but clumping bamboos are very different.
All bamboos are grasses – just very, very big ones. And just like the grasses in your lawn they either run or they clump.
Running bamboos send out underground stems or runners, which then send up shoots known as culms. These culms can pop up anywhere – even 10 or more metres away from the main plant - and they are strong enough to punch through asphalt and thin concrete and dislodge pavers.
Running bamboos are very hard to eradicate as they can quickly regrow from these underground parts, even when the main plant is removed. Many are listed as weeds.
Clumping bamboo, on the other hand, sends out new culms as side shoots from the parent plant (these may even arise inside the existing clump). This naturally keeps the plant in a dense clump and makes it much less likely to go feral. New plants generally come from divisions taken off the central clump, so clumping bamboos have come to be known as “escape-proof” bamboos.
Why use clumping bamboo?
Clivia flowers contrast with these candy striped bamboo stemsClumping bamboos offer some fantastic advantages over traditional hedging or screening plants.
Size – Screening and hedging plants will generally include a description of their height and width, but these descriptions can be very rubbery – "Height 3m to 6m", for example – and your local conditions can greatly affect their growth. You may be expecting 3m from a plant only to find it won’t grow above 2m at your place. Clumping bamboo, though, is very reliable. You want screening to 3m? Buy a 3m variety. You want 10m? Buy a 10m variety. If in doubt, buy taller than you need and prune the tops off.
Speed – Traditional screening and hedging plants can take 10 years or more to reach their full size. Under ideal conditions clumping bamboo will reach at least two thirds of its height in 12 to 18 months and will be forming a quality screen in much less than two years. You can expect a hedge to be knitting together in as little as 12 months.
Appearance – Clumping bamboos bring a range of fantastic visual textures, forms and colours to your garden. Their foliage adds a lush, tropical feel, and different varieties add an extra "Wow!" factor with with variegated foliage and coloured or striped stems.
Maintenance and pruning – Clumping bamboo is very hardy once established but needs reliable water to look its best. This makes mulching essential, though mature bamboos typically drop so many leaves that they mulch themselves.
A painted fence gives bamboo a colourful backdrop
Clumping bamboos appreciate being fed once or twice a year. A high-quality slow-release lawn fertiliser supplemented with occasional organic liquid feed is ideal. Generally the only pruning is to remove older shoots as they droop out or to restrict height. Some varieties are grown as dense hedging and these can also be pruned as needed to keep them to the required width.
Foliage coverage – Once you’ve decided the height you want you’ll need to decide on foliage density. Some bamboos maintain foliage cover from top to bottom, while others can be more open or have bare lower stems for the first metre or two. These are ideal when you want to underplant or to use the bamboo against a feature wall or in an area where width is an issue.
Climate range – Although bamboos are generally thought of as being tropical sub-tropical plants, there are some that will grow in cold and even freezing conditions.
Can clumping bamboo become a problem?
Clumping bamboos are perfect for Asian-inspired gardensThe bamboo’s dense clump will physically block other plants from growing within that area. Bamboos are also mildly allelopathic, producing chemicals that prevent the growth of other plants directly around them. This isn’t uncommon in the plant world - even sunflowers do it - and it will only impact the area directly beneath the plants.
As the clumps age they will spread outwards and might get wider than you want. You can use a sharp spade to trim off, lift and transplant, or appropriately dispose of, the advancing sections.
It is important that any waste material, especially roots, is correctly disposed of through your local green-waste collection service. One of the biggest causes of foreign plants escaping into the bush is illegal dumping of green waste, so make sure you do the right thing.