Couchgrass also known as hair barley, cordgrass, or creeping quackgrass, are perennial herbaceous root weeds in the sweetgrass family. Some species develop long, underground rhizomes that have the ability to form roots at each individual node. Even from small root remnants, new plants can develop again. Therefore, when controlling couch grass in lawns, it is especially important to completely remove all root debris from the soil. Elymus repens form erect, glabrous or drooping culms and can grow up to 120 cm tall, depending on the species. It spreads via runners, which this plant forms en masse.
- Scientific name: Elymus repens
- Belongs to the plant family of sweet grasses
- Reaches heights of growth between 40 and 120 cm, depending on the species
- Use as a medicinal herb
- Couch grass is shallow rooting
- It forms long underground rhizomes
- Strongly runner forming
- Proliferates exceptionally strongly
- Flowers from June to September
- Grows on fallow land, in gardens and fields
Table of Contents
When couch grass occurs sporadically, it is often recommended to cut it out with a sharp knife or a special weeding tool. It is best to start before the couch grass flowers or forms seeds, because it not only spreads by runners, but also reproduces by seeds. When pruning, always try to remove as much of the root system as possible, preferably the entire root. However, this stubborn plant cannot be removed completely by pruning. As a rule, there are always isolated root remnants left in the soil, from which new plants develop again. Even the smallest root remnants are sufficient for this.
Digging up not recommended
Removing couch grass by digging or digging up is, like cutting it out, only recommended to a limited extent or not at all. On the one hand, the roots are literally cut to pieces and the spreading is supported rather than prevented. In addition, the lawn does not really look better afterwards.
If you want to try it in spite of everything, it is better to take a shovel instead of a spade and follow the course of the root to finally remove it. You should be very careful when doing this, as the roots tear off relatively easily and are then hard to find. Even here, parts of the roots always remain in the soil, which are then again easily able to form new runners and promote further spread of this weed.
Note: If digging is not carried out with extreme care, it tends to achieve the opposite of what is intended. As a rule, this method is rather inadvisable
- Lay out plastic film
- Many an amateur gardener has achieved good results with opaque film.
- This method of control is quite lengthy.
- After this treatment, the lawn must be replanted.
- A simultaneous death of lawn grasses, is not to be avoided thereby.
- The area in question is completely covered with dark foil.
- The edges should be weighted down with stones, wooden beams or similar.
- Neither rain nor sunlight should penetrate to the ground.
- The foil is left in place for at least one gardening season.
- It is better to leave it for 6-12 months, the longer the better.
- In the best case, the entire couch grass will die.
- After this time remove the foil
- Then thoroughly work the area with a cultivator.
- Carefully remove all dead plant remains.
- Subsequently reseed the area
Note: When reseeding, be sure to use high-quality seed to avoid re-growth of couch grass or other hardy weeds.
Control with chemical agents
Total herbicide Renofluid Royal.
If conventional means have not been successful, the only option usually left is to replant the lawn with the help of the herbicide Renofluid Royal, for example. This method is often the safest and most promising in the case of very heavy weed growth in the lawn.
First, you need to remove the old lawn, about three weeks before you can start reseeding. During these three weeks, the lawn is no longer cut. A few hours before applying this herbicide, preferably in warm weather, one should water the area. Then apply the herbicide according to the manufacturer’s instructions.
After about 1-3 weeks, depending on temperature and weather, the grasses as well as couch grass and other lawn weeds will be brown, meaning they have died. Now comes the most important part, the lawn thatch must be thoroughly removed. To do this, the area must be deeply scarified. In the process, the lawn felt is torn up at the surface of the soil and the soil is loosened superficially. When scarifying, be sure to also work crosswise.
After scarifying, the entire lawn felt is thoroughly removed with a rake or lawn comb so that the open soil is revealed. Possible unevenness can then be corrected with sharply washed sand or a sand-soil mixture. Now the reseeding can be started. As already mentioned, it is essential to use high-quality seed.
Lawn weeds can certainly not be prevented completely. However, there are some preventive measures that can be taken, because a healthy and dense lawn is much less susceptible to couch grass and the like. The right care of the lawn plays a decisive role here, because if the care is not right, weeds such as couch grass can settle and spread very quickly.
Proper care includes watering the lawn, fertilizing, mowing and scarifying. It is best to water the lawn once a week. You should water thoroughly, about 10 liters per square meter, so that the water can seep into the soil to a depth of at least 15 cm. In contrast to loamy to clayey soils, sandy soils require more frequent watering, possibly every two days in the summer. Never water in the blazing midday sun, as this could result in burns to the stalks.
In addition to watering, the lawn must be dethatched regularly, once each spring and fall, and then cleaned of lawn thatch. Mowing is no less important. The first mowing of the year should be done in April and then regularly. A stalk height of about 4 cm is optimal.
Since lawn grasses also lose nutrients when mowed, fertilizing is another important step in keeping the lawn healthy. Fertilizing should be done about 6-8 weeks after the first cut, and then again in the summer and a final time in the fall. If fertilizing is not done at all or too little, the lawn will get gaps in which mosses and especially weeds like couch grass or clover can settle.
Tip: For watering the lawn, commercial lawn sprinklers are a very good and recommendable alternative to watering with a watering can or garden hose. A fertilizer truck allows lawn fertilizer to be distributed much more evenly on the lawn than by hand
- Remove weeds even before the lawn is seeded.
- Prevent the growth of lawn weeds from the outset if possible.
- To do this, thoroughly remove weeds even before planting a new lawn.
- Especially remove couch grass, clover and dandelions as thoroughly as possible.
- Remove weeds before they flower or form seeds.
- Always remove the complete root as well.
- Otherwise, the couch grass will be back in a few weeks.
- Cause for the growth of couch grass
There can be various causes for the growth of couch grass in the lawn. The most common is a nutrient deficiency, because lawn grasses have a relatively high nutrient requirement. In the event of a deficiency, the grasses become weaker and more and more gaps form in the lawn, which in turn leads to very adaptable weeds such as couch grass gaining the upper hand and being able to spread at breakneck speed. This is exacerbated when water becomes scarce in addition to nutrients.
Another cause for the formation and spread of couch grass is a low-quality lawn seed. Here, especially the seed ‘Berlin Tiergarten’ is to be mentioned, which tends particularly strongly to weed. Such seeds are bred for fast growth, which is why they contain mainly inexpensive forage grasses. These grasses shoot up very quickly, but do not form a closed turf, as is actually desired for lawns.
Note: Due to the fact that couch grasses spread very quickly, you should start fighting them as early as possible. The longer you wait, the harder it will be to get rid of them completely
Frequently asked questions
What should I look for when using weed killers?
Weed killers are chemical substances that should only ever be used when all other measures have been unsuccessful. Before buying, be sure to seek advice on which agent is effective against which weeds. Weed killers for the lawn are usually designed to be effective only against certain weeds. However, there is no agent specifically against couch grass. Accordingly, only total herbicides such as Renofluid Royal come into question here. However, these do not distinguish between weeds and crops, so they should be used selectively. When using such agents, one should always strictly follow the manufacturer’s instructions. Among other things, it is important that they should not be applied near bodies of water.
Can root weeds such as couch grass be prevented?
The best way to prevent the formation of root weeds is to properly maintain the lawn, i.e. fertilize, mow, water and dethatch. Otherwise, it is helpful to thoroughly clear the soil of all weeds even before establishing a lawn. To permanently banish couch grass from the lawn, its reproduction should be stopped. Since they reproduce both by seeds and underground runners that can grow about a meter in all directions in the course of a year, it is important to consistently remove couch grass before it blooms, without leaving root residues in the soil. However, this is very difficult.
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