How To Kill Couch Grass (aka Elymus repens etc.)

If A Couch Root Is Cut In Two You Get Two Couch Plants Growing. But Cut It into 100 Pieces & They’ll All Die. Rotovating Couch Can Kill It. Here’s How To Kill Couch Grass!

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https://commons.wikimedia.org/wiki/File:Illustration_Elytrigia_repens1.jpg

I’m forever reading how rotovating couch grass will just increase the number of plants. True, it does if you don’t understand how farmers use rotovators to kill couch. Because the turret is the rotovator can be your weed killing enemy or your weed killing friend if used correctly.

Couch grass spreads by rhizomes. Rhizomes are this fleshy long sub-surface roots that become a tangled mess in gardens. they are capable of producing new shoots every free inches and each shoot can produce a new plant. Get it and it’s a nightmare. But it needn’t be!

Gardeners to frequently claim that sounds need to be careful y removed from the soil by deep digging and hand removal of every single piece of rhizome. That is very hard tedious work and I’ve never subscribed to it.

I once inherited some land that had beds of luxuriant couch growing on it. It was land that hadn’t been cultivated in years and was rife with this pestilent weed. Even the rabbits avoided it!

I removed it without digging in just a few weeks. In fact 95% or more was removed in just one day.

Below I’ll explain how I did it. These are methods that kill couch grass naturally, without chemicals, by physical methods.

But first let’s look at how couchgrass grows as it is key to how to destroy it.

How Couchgrass Grows

Couch grass propagates in two ways. The first is via its roots, called rhizomes. They are long sub-surface roots that grow very long. Every few inches they have the ability to produce a shoot that becomes a new plant.

The second way they propagate is from seed. This only happens where the grass has been allowed to flower. Keep it cut and it cannot form seeds.

For any plant to grow and thrive it needs to photosynthesise. For this to happen light is needed. Without daylight all plants eventually die.

How To Kill Couch Grass: Method One

Plough or dig the ground and pull the rhizomes out.

This method is quite capable of removing 95% of the rhizomes. However some will almost certainly be left. So be patient and let it shoot. When it break through the soil surface dig it out. With luck you’ll get 95% of it. BUT some will be left. So repeat several more times until no more roots shoot and leaves break the soil surface.

On a large scale I ploughed and used a spring tine harrow to pull the rhizomes up. Then used an Acrobat to gather the rhizomes for burning or removal.

The above method always works PROVIDED we are patient enough and get every bit of rhizome out. Too often I see people get 95% of their roots out and then plant up. Within weeks they have couch grass growing and spreading. This method takes patience.

How To Kill Couch Grass: Method Two

Imagine you have a couch grass rhizome that is a foot (30cm) long. Chop it in half and you’ll soon grow two plants.

This length of root probably has 5-6 potential shoots ready to grow. So if you cut it into 5-6 pieces you will probably get 5-6 new plants. If you’ve used a rotovator to chop it it up you’ve just multiplied the problem.

Now imagine you chopped it up into twenty piece. You will not get 20 new plants. You only get 5-6 at most. And each one will have less root and hence fewer food reserves to grow the new plant.

Now imagine you chop it into 100 pieces. Some of the potential shoots will have been destroyed. Others will have just minuscule length of rhizome left to grow from.

If a few days after you rotoavate you go back and rotovate again more shoots will be destroyed. Do this several times with a few days between each treatment and its possible to totally destroy couch grass.

The rotovator used needs to have a powered fast moving rotor and be run art high speed whilst moving across the ground very slowly. Otherwise it just chops the rhizome into nice lengths and encourages growth. Standard garden rotovators rarely have powered rotors capable of high speed operation at minimal forward speed. They often rely on the rotors to move them forward.

Best Rotavator Advice

So my best advice is to use a wheeled rotovator that has independent fast rotating rotors. It’s vital that the couch rhizome is cut up very small or this method will fail and could even make it worse. The ideal situation is to use a tractor mounted rotovator and move forward in low ratio.

Seed Grown Couch Grass Destruction

If you’ve destroyed the rhizomes by the above methods you still need to look out for regrowth from seed. Seedlings can be killed, before they produce rhizomes, by hoeing or other cultivation methods. Leave them to form rhizomes and they’ll soon take hold and cause no end of problems.

Couch Grass Creep

However we control couch grass, if it is on adjoining land, it will soon creep back to our cleared land. The only way to control it is to create a barrier, or a no couch barrier.

If you leave a width of land around the cleared plot it is easy to hoe, or otherwise cultivate it, as soon as couch is detected.

Keep that barrier strip clear and couch will not creep back.

Other Couch Grass Clearance Methods

I don’t like covering soil for lang periods. But if you totally exclude light from couch for long enough it will die. But don’t forget a barrier strip. Because if part of the plant is not covered it will keep the covered bits alive and ready to grow once uncovered. Rhizomes can run many yards and the parent plant can be yards away keeping what has been covered alive for years if need be. Weeds are good at survival!

Couch grass aka Many Names

Couch is also know a switch and a number of other local names.

The Latin plant name also tends to confuse as it’s a plant that has frequently been renamed. When I was taught it was Agropyron repens, others have called it Elytrigia repens . Repens means to creep so at least they agreed on that bit.

Another Latin name is Elymus repens. The link here explains why some latin names change.

Latin names are meant to remove confusion. It doesn’t work for this species.

Finally .. this post doesn’t address how to kill couch grass in a lawn. I’ll cover that in another post.

PS, predictive text keeps changing couch to coach and if you see the wrong spelling it shows how poor I am at proofreading!

Finally .. how is couch pronounced? It’s cooooch grass …. not couch as in a sofa! But some people just refer to it with swear words and I sympathise with them.