How To Stop Comfrey From Spreading? (No Harsh Chemicals)

  • By: TheWalledNursery
  • Time to read: 6 min.
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Comfrey is a shrub that grows across Asia, North America, and Europe. It can grow as tall as five feet and has blue, purple, or white blooms.

However, it spreads quickly and is even toxic. You don’t want this plant anywhere on your property.

There are multiple ways to remove the comfrey without using a harsh chemical. Organic acids work very well to kill the invasive plant. You can also dig it up by the roots or cut it down with a weed trimmer.

See below full details on how to stop comfrey from spreading in your garden.

Why Should I Remove Comfrey From My Yard?

Comfrey is an invasive bush. It spreads quickly and is harder to deal with the longer you let it grow. It’s best to remove it from your property when you first identify it.

The species is known to overcrowd gardens, killing other plants. The roots also spread fast and choke other plants you’ve been working hard to grow.

Not only that, but comfrey is a toxic plant. It’s carcinogenic and can even cause liver damage if eaten! It can hurt humans and pets, so make sure you get rid of it- especially if you have children or pets at home.

There are plenty of ways to remove this plant without using harsh chemicals. Avoid using chemicals when you can since they can mix with the groundwater.

How Can I Remove a Comfrey Plant?

The best way to stop a comfrey plant from growing is to remove it altogether. It doesn’t take very long to spread, so you’ll need to act fast.

The roots of the comfrey bush dig very deep into the ground, making it harder to deal with.

If you miss even a tiny piece of the root, the plant can quickly grow back. You’ll likely have to remove it two or three times to stop it entirely.

While fighting comfrey plants, you’ll need to keep a close eye on your garden for signs of it returning. These are all the chemical-free methods you can use to stop the plant:

Use an Organic Acid

First, you can use an organic acid to kill the comfrey plant. These acids are different from chemicals that you would use- they’re organic and shouldn’t cause environmental damage.

Citric acid is one of the best options. You can find this in lemons! Mix one quart of white vinegar with four ounces of lemon juice in a spray bottle. 

Next, spray the comfrey plant with your acid. You want to reach the leaves, roots, and stems. You’ll need to repeat this every day until the plant dies. It can take a while, but citric acid should kill the plant down to the roots. 

The acid breaks down the cell membranes of the plant. It works immediately, and you should notice the plant wilting even after the first application. 

Dig the Comfrey Plant Up

Your next best option is to dig the plant out of the ground. You’ll need to ensure that you’re getting everything out; even a small section of root will allow the plant to regrow and sprout again.

The roots grow out about three feet, so you’ll also need to check a wide area around the plant. This process is complicated in a garden because you won’t want to uproot your other plants.

Cut the plant down a bit, then dig about three feet away from the plant. Work your way down to the roots.

Doing so loosens the earth enough to pull the entire root out! It should be a large ball at the center.

However, this takes a lot of effort and physical strength, especially if the plant is large.

Cut the Plant Down

If the comfrey plant is small enough, you can cut it down with a lawnmower or weed whacker.

You’ll need to do this over and over again until it never grows back. 

Cutting the plant before it can flower also stops it from spreading above ground. The roots, however, will continue trying to sprout for a long time.

This method works best when combined with an organic, homemade acid.

Smother the Plant

Smothering is also effective at stopping comfrey from growing and spreading. Cut it down; you want it level with the ground.

Cut large plastic sheets to cover the entire plant. You can set them in place, then use stakes or rocks to keep them there.

Keep in mind that this solution takes a very long time. You won’t be able to move the mulch until two growing seasons have passed.

Make sure you throw away the soil there later so it doesn’t regrow.

Many gardeners use black plastic mulch to get the job done. You’ll only be able to use this method if there aren’t any other plants growing near the comfrey bush.

Uproot the Plant With a Tool

Lastly, there are uprooting tools on the market that you can use to deal with comfrey.

Start by cutting the plant down, but leave about six inches to a foot of it in place.

Next, use your uprooting tool. The tool should grab onto the stem and let you yank the plant out, roots and all!

This method works best when the plant hasn’t had the chance to spread its roots far. 

You’ll also need to be strong enough to pull the roots out forcefully. If you try and it’s extremely difficult, don’t hesitate to get help! You wouldn’t want to strain yourself.

Afterward, make sure to inspect the soil left behind very closely. You can pick out any roots you find there with a garden rake.

When Should I Call the Pros?

There’s no shame in contacting professionals to remove the comfrey plants, especially if you’re trying to deal with an infestation on your own!

This plant is dangerous and even banned in some areas. The sooner you can get comfrey plants taken care of, the better.

Many professional landscapers and gardeners can help you remove the plant fully so that it has no chance of coming back.