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Miscanthus sinensis, also known under the names Chinese reed and elephant grass, is a common sweet grass that is often kept as an ornamental grass and privacy screen due to its dense growth. Like other grasses, this extremely hardy species can multiply quickly and form runners. Many gardeners associate the word stolon with the need to contain roots so they don't drive away other plants or damage structures. But is that necessary with reeds?

Caution: risk of confusion!

Please note that Chinese reed is less likely to be confused with other plants that are also called elephant grass. What they all have in common is that they grow luxuriantly, tall and sprawling, which is why the term elephant grass lends itself accordingly. In addition to Miscanthus sinensis, these are:

  • Napier grass (bot. Pennisetum purpureum: 450 - 750 cm high
  • Giant Chinese reed (bot. Miscanthus giganteus): 300 - 400 cm high
  • Ravenna grass (bot. Saccharum ravennae): 100 - 450 cm in height

They all need a rhizome lock to keep the strong urge to spread to suppress. However, the big difference between the plants is the height. In Central Europe, Miscanthus sinensis is usually only two meters high, in rare exceptional cases up to three meters high, while the elephant grass often grows larger and more expansive. You should therefore pay attention to the botanical name when purchasing, as the individual grasses require significantly different care.

Chinese reed - zebra grass - Miscanthus sinensis

The grasses also spread rapidly in the ground and can cause major damage. Chinese reed, also called Miscanthus condensatus (synonym), is not really a candidate for a root barrier, except for a few situations.

When does a root barrier make sense?

The classic Chinese reed is the only Miscanthus species that does not really need a root barrier. However, in a particularly favorable location, the roots can spread quickly and up to five meters in all directions. In the long run, this can lead to major damage. In particular, you should isolate specimens near the following elements with a root barrier:

  • Tube
  • cables
  • garden ponds
  • house walls
  • Paving stone paths
  • Paving stone terraces
  • building foundations

With these elements in particular, it makes sense to pack up the reeds and suppress the strong sprout. Even robust plastics can be penetrated over time when the plant's runners are older and stronger. The big problem with Chinese reed is the growth rate. Compared to other types of reed, the stolons form quite slowly, which is not a cause for concern in the first few years after planting. Then suddenly there is serious damage to nearby structures. The advantage: the strong budding is a sign of an ideal location, which makes it sensible to set a barrier.

tip: The subsequent installation of a rhizome barrier is unproblematic with Chinese reeds, but requires a little more work, since all runners that have already formed must be shortened. The costs remain the same, only the time required to install the barrier is significantly higher.

size and cost

Purchasing a rhizome barrier for the Chinese reed to limit the urge to spread is not really that expensive. However, this depends on the size and previous spread of the Chinese reed. Retrofitting is usually more expensive, since the plants are often larger and therefore require a larger root barrier.

High-density polyethylene (HDPE) root barriers, such as those used for bamboo, are recommended. These should be selected with a thickness of 2 mm and a height of 70 cm, which costs an average of eight to ten euros per meter. The order length is calculated as follows:


If you plant the rhizome barrier together with the reeds, the necessary length is calculated as follows:

Planting hole diameter x 3 = order length

On average, one square meter is required per copy, which brings the typical order length to three meters. That would be acquisition costs of 21 to 30 euros.

Subsequent suspension

The order quantity of a subsequent block is calculated in the following way:

  • mark the four corner points of the reed
  • Draw a 2m - 3m line from each corner point
  • mark again
  • connect the outermost markings with tape
  • measure diameter
  • Multiply diameter by 3

Since a root network has already developed before the barrier is retrofitted, a larger order quantity is necessary in order to be able to place it and not damage the roots. You usually have to pay around 70 to 150 euros for retrofitting.

You still need one closure rail, which you should best obtain from the same supplier. These are offered on average for prices of 25 to 40 euros for a height of 70 cm. Other providers equip their locks with an adhesive surface that closes them and does not cause any additional costs. When calculating the order length, be sure to note the desired final size of the Chinese reed. If you want it to continue growing, be sure to order more to give it enough room for its roots. This is the only way for it to absorb nutrients and water from the soil.

tip: The use of garden fleece or roof foil for a flat roof as a rhizome barrier is theoretically also possible, but not recommended in the long term. This is because the ends need to be joined via suture or other closure devices, allowing the roots to spread in one direction.

Possible problems after installation

If you decide to set up a ban, it is important that you understand the potential risks. These mainly affect other plants and the vitality of the reed:

1. Stunted growth of neighboring plants

If the distance of one to two meters to other plants is not possible, they can suffer from stunted growth due to the rhizome barrier. Since these hit the barrier with their roots, sufficient nutrients are no longer absorbed, which leads to a deficiency. So plan the placement of the barrier well so as not to put other garden plants under pressure.

2. Uneven aspect ratios

It is also problematic if you do not place the Chinese reed in the middle of the root barrier. One side of the reed suffers from a nutrient deficiency because the root strands there do not have enough space. Therefore, you must be careful to place the reed as centrally as possible.

As long as you observe these points, no problems should develop after installation. Since the barrier reduces the space for the reeds and other plants, it must be placed in such a way that there is no lack of space. Transplanting to a location is sometimes recommended.

Limit Chinese reed: instructions

If you want to limit your Chinese reed with a root barrier, you only have to install it after purchase. For this you need:

  • spade
  • shovel
  • garden gloves
  • saw

Then do the following:

1. planting hole

The first thing to do is to dig the planting hole. If using the reed with the dam, measure the required size using a tape. If the barrier is 70 cm high, dig the planting hole between 60 and 62 cm deep. In the process, remove any root debris that you come across.

2. Dig up the plant

If it is inserted later, the plant is first carefully dug out of the ground. To do this, mark out the required pit and work your way from the outside to the inside. Check here whether runners have formed, which you can remove with the saw so that Miscanthus sinensis cannot spread further. In the case of particularly large specimens, you should not dig up the plant completely from the ground, but only dig out the earth along the cordoned off line and remove the foothills.

3. Use root barrier

Now place the root barrier in the hole, run it along the edge and close it with either the splint or the adhesive device. If you have decided to use an adhesive barrier, it is imperative that you wait for the manufacturer's drying times. If the adhesive surface is not allowed to dry completely, pieces of soil will get into the interface, which means that roots could penetrate through the barrier. For this reason, you should definitely wait until the recommended drying time has passed.

The root barrier must protrude about 3 to 5 cm from the ground. This is the only way to prevent spreading directly under the surface of the earth.

4. Insert plant

The plant is then placed in the center of the pit. The help of a second person is a good idea here, so that the reed is really placed in the middle. Fill the pit with the excavated earth and fill any gaps on the outside of the barrier with earth or sand. Proceed in the same way with upgraded specimens.

5. Compact soil

Finally, compact the soil with your feet. Kick them firmly and don't miss an inch. Now the lock is in place and effective.

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