I used to love my asparagus fern, or should I say ferns? It made for pretty additions to the flowering bouquets I put together for weddings and other special events.
Recently, I had to learn to kill my asparagus ferns. Yes, I only bought one and planted it. Soon, however, it became many, hence the singular “fern” to multiple “ferns.”
This is not an evergreen perennial you would want to take over your garden (as you’ll learn shortly).
So how to kill asparagus fern?
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How to Kill Asparagus Fern?
For isolated areas of fern growth, dig them out and remove all roots and tubers, or mow them down. Another is solarization, where the sun bakes the plant after covering it with plastic tarp held down with rocks or bricks. Another is the cut-and-paint method for small asparagus fern patches, and spraying with a 1% glyphosate systemic herbicide for large areas.
Methods of Killing an Asparagus Fern
To get rid of your emerald ferns, you can try these methods:
Dig out the Plant
I’ve tried digging out many asparagus ferns with mixed results. I found that this method is most effective if you only have the fern growing in a few isolated spots.
When I dig out the emerald fern, I also choose fall or winter and ensure the plant hasn’t yet flowered.
With a trowel, I thoroughly loosen the soil around the plant. Once the ground isn’t compacted anymore, I firmly take hold of the base of the asparagus fern and pull.
Sometimes the fern comes out completely, with almost no tubers left in the ground, while at other times, I really struggle. When I struggle to uproot the fern, I water the soil first, just enough so it is moist.
Since the plant can easily regrow from any tubers left in the ground, it’s important to dig up the soil once the fern is out and pull out any pieces of root and tubers.
Mow, Mow, Mow
Mow. Repeatedly. With a string trimmer or even pruning shears, I cut the asparagus fern, removing all the feathery stalks and leaves, until it is at soil level.
I’ve found that this helps to control my fern from growing and spreading. How does this method help?
Since no berries or seeds are produced, this eliminates the fern spreading via seeds. And by repeatedly cutting the plant, it uses all its energy on regrowing.
Eventually, the tubers will starve and naturally kill the fern.
This is a solution that will take a very long time, and there are quicker ways to get rid of your asparagus fern.
For another natural killing option, I have tried solarization before. I use this method during the hottest time in summer, but unfortunately, this works best if your summers are H-O-T.
Solarization sterilizes the soil to get rid of insect pests, bacteria, and underground roots.
When I solarize, I use a string trimmer to cut my asparagus fern to soil level (like in the method above). I then moisten the soil with water and cover the plant with a plastic tarp that is clear.
I weigh the edges down with something heavy, like rocks.
The rays of the sun will heat the soil, and the radiation warms the tarp further, moving this process along. This whole baking process takes about 4-6 weeks and the area will be rid of my asparagus fern problem.
Cut and Paint
Now for the not-so-natural killing methods.
I prefer the cut and paint method to kill asparagus ferns because it means I don’t have to spray a large area with herbicide.
To get started with this method, I have my herbicide ready in a little spray bottle or paint tray. I cut the fern to the ground level and immediately spray or paint herbicide on the cut areas of the stems.
The plant absorbs the herbicide through the stems, resulting in the underground roots dying.
For the best results, the herbicide I use has an 8% concentration of triclopyr.
For a large asparagus fern invasion, I prefer this method for its effectiveness. Mowing a large colony of ferns or digging them up is too time-consuming, and it isn’t always very practical.
With this method, I firstly (and almost religiously) check my local weather reports. I need at least a 2-day period where it will not rain.
Once reports of a dry spell come through, I spray the whole asparagus fern colony with an herbicide that contains a 1% concentration of glyphosate.
Dry weather ensures that the herbicide can do its job and kill the asparagus ferns as rain will simply wash the herbicide away.
This method generally works within 14 days as the ferns will yellow and then die.
Why Would You Want to Get Rid of an Asparagus Fern
An asparagus fern also called an emerald fern or lace fern, is an evergreen perennial, meaning that it comes back year after year as it continuously moves between growing and dormant seasons.
It is also a low-maintenance plant that’s very drought-resistant. With its established root system, you’ll find that it is difficult to get rid of this fern.
As the seeds easily spread via birds and the plant quickly regrows from even the smallest tuber left in the ground, it is virtually indestructible.
Possibly even worse is that this plant takes over other garden areas. Native plants are displaced, and the fern prevents these plants from regrowing or reestablishing.
Frequently Asked Questions about How to Kill an Asparagus Fern
What kills asparagus ferns?
If your asparagus fern has colonized beyond control, it is best to use a herbicide that contains 1% of glyphosate. For smaller patches where the ferns grow, you can repeatedly mow the plants down to soil level, use the cut and paint method, solarize them, or dig out the ferns.
Are asparagus ferns invasive?
Asparagus ferns are invasive in several worldwide locations, including Florida, Hawaii, and New Zealand. The reason is that this fern is able to easily regrow from small root segments and once it has an established root system, it’s difficult to manage its growth as it spreads quickly.
Do asparagus ferns spread?
Asparagus ferns spread quite ferociously. These ferns spread in two ways; one is through birds that disperse seeds and the other is vegetatively via the tubers. These can sprout quite a distance away from the main plant and they easily form colonies, displacing native vegetation.
The Final Kill
Asparagus ferns have the ability to take over your whole garden as their seeds spread.
However, there are ways—both natural and chemical—to ensure this doesn’t happen as you don’t want your ferns to displace the other plants in your garden.
Use an herbicide for large asparagus fern colonies or try out organic killing methods like mowing, solarization, and digging.
I can only wish you good luck. Happy fern killing!
Daniel has been a plant enthusiast for over 20 years. He owns hundreds of houseplants and prepares for the chili growing seasons yearly with great anticipation. His favorite plants are plant species in the Araceae family, such as Monstera, Philodendron, and Anthurium. He also loves gardening and is growing hot peppers, tomatoes, and many more vegetables.