How to Control, or Kill and Remove Daylilies From Your Garden

Daylily weeds can be very invasive to areas around your home, or your personal gardening space. They can also be quite difficult to get rid of, so it's important to act quickly once you've spotted them. In this article, amateur gardener Jason White examines several different methods to rid yourself of daylilies, and how to stop them from coming back.

Daylily Plant

Here’s something that less experienced gardeners may not know. Those beautiful daylilies that might be growing in your garden are a lot more dangerous than they look. Confused? It’s not really due to them being poisonous (though if you have a cat, they should stay away from all your lily plants– a topic for a different article!). As gorgeous as daylilies might be, they are considered invasive, and some varieties are considered weeds.

While it may be shocking to hear this, it’s unfortunately true. Daylilies are perennials, which means they come back each year and can be difficult to control. Containing them can be very tricky if you don’t know what you’re doing, and being unable to do so can really spell disaster for much of your garden. What’s a gardener to do? Well, we have the answer!

We at All About Gardening have written this article to let you know why you should keep these plants under control, plus how to get rid of them. We’ll give you a rundown on the different methods to try, plus other tips and tricks to keep them away. Lastly, we’ll also tell you what you need to know about keeping daylilies in your garden because they are really beautiful plants regardless of how much trouble they are. Let’s get down to the details!

When Daylilies Go Rogue

Orange Daylily
The orange variety spreads prolifically.

Daylilies have been around the US for generations. The orange daylily in particular has been used as an ornamental since the 19th century. It’s become a favorite flower type for many gardeners over the many years for many reasons. Besides their obvious beauty, they are actually incredibly easy to care for. They also spread prolifically– too prolifically.

True enough, these days, while they are still in favor with a lot of gardeners, you’ll find that if you give daylilies an inch, they will take a mile. With them being very hardy plants, you can see why this can make them a problem.

True enough, daylilies are highly invasive. The classic orange daylily is actually considered a weed in some states. This orange flowered weed can take over plenty of space in no time at all. They will be battling your other plants for resources that they will not be able to spare. You could see them outright killing other plants in your garden as they spread. While this is true of all daylilies, the orange daylily we mentioned earlier is the most pervasive.

These plants are common throughout the eastern United States and on some parts of the West Coast. However, they can grow in most places, especially in places where they may have escaped from plantings. They are well known for attracting pollinators like butterflies, which can be beneficial to other plants.

Their thick tubers are difficult to kill, and many may be left behind if you are not thorough about getting rid of them. When this happens, they will simply regrow, and you will be right back where you started. To make matters worse, in their first year, daylilies do not grow flowers, so it may be difficult to tell why your other plants are dying!

How to Kill Daylilies

Cutting Daylilies
There are multiple ways to rid your garden of daylilies.

Now that you know why daylilies are bad for your garden, it’s time to look at the different ways to kill them. There are a few methods you can try, some of which should be taken as a later approach than others. Study this list to learn what you can do to control your daylily infestation and keep your garden free of this pesky plant.

Hand-Weeding

Hand Weeding Garden
Hand weeding is the old fashioned way, and is usually one of the easiest.

You can make a lot of progress with your daylily problem by simply using your hands and some tools. This is usually preferable to digging your plants out, since this doesn’t generally disturb the other plants you’ve established. Hand-weeding in particular is effective when done regularly, and counts as good exercise too!

Hand-weeding must be done regularly if you really want to make a dent in the problem. Attending to your plants and checking for daylilies must be done once a week, so ensure that you set aside enough time to do a thorough job. Doing this will deter growth, as it kills seedlings and weakens established roots and tubers. Afterwards, there’s a good chance that the plant itself will simply give up and die.

You can also use tools, such as hoes and trowels, to make the job easier. This can help you dig out the roots without resorting to more extreme measures of digging up a whole area. This is a faster, more permanent solution, but it’s good to have all your bases covered. Try using a combination of hand-weeding and tool-weeding to improve the situation.

Dig Them Out

Digging Up Weeds in Garden
Digging up daylilies is also an option if you can’t do it by hand.

If you’ve determined that the problem is a bit larger than hand-weeding can handle, then it may be time to up the offense. Digging the daylilies out can be a better way of handling the problem. However, take care not to damage any other plants that may be in the way of your digging. Be thorough about your digging and try to go through the soil with a hoe to make sure you’ve gotten most of the roots out.

Chances are you will need to do this process several times over the period of a few weeks. A good strategy is to get as much as you can out of the way, then wait for the remaining daylilies to re-sprout. Then repeat the process until you find no more daylily sprouts.

This may take 6 to 8 weeks, so be patient about this process. Despite the extra work, it is usually successful. Remember that daylilies are very persistent and will grow back if even a little bit of the root system is left behind. As such, be careful about how you dispose of your daylilies. We’ll cover more on this in our tips section.

Mow and Mulch

Mowing and Mulching Weeds
Mowing and mulching allows you to reuse the remnants of the daylilies through mulching your garden.

Another method of killing daylilies is the good old “mow and mulch”. This will work if you find that you have plenty of daylilies growing on your lawn, likely leftovers from previous plantings. For large areas like this, use a lawn mower on its lowest blade setting and cut through all the daylily plants you see. If you have them growing in an area that is less accessible, using a weed whacker will do the same job, just with more precision.

As you may have surmised, this is only the first part of the operation. You should then proceed to give the areas you mowed over a good layer of mulch. Mulching the area will deprive the plant of sunlight, and will thus prevent further growth. Use your favorite mulch and cover the mowed areas with at least 6 inches of it.

You may find greater success if you place a biodegradable barrier, such as newspaper, as the first layer before mulching. Simply add more mulch if you find new green daylily growth popping up from it. You can also opt to apply mulch to areas you have hand-weeded, as this will provide a similar effect. Bear in mind that the mulch will have to stay there for a year to kill every part of the plant.

Plastic Barriers

Black Garden Sheet
Using a black plastic garden barrier can prevent the sun from reaching the plant.

Here’s another method that may work for you. Similar to mulching, you can deprive daylilies of sunlight by covering them with opaque, black plastic sheets, or green plastic fencing. This also has the added benefit of insulating heat and using the extreme temperature to kill the remaining daylilies. Ensure that the plastic is secure by weighing it down with stones, or by staking it into the ground. Check for damage every now and again so you don’t accidentally let any sunlight in.

This method is simple and effective. However, it will require you to cover a large portion of your garden with plastic. It will also take a good bit of time. The plastic must cover the affected area for 6 weeks to 3 months before you should remove it. As such, a big area of your garden may be out of commission.

Bear in mind that you should purchase plastic sheets that are at least 6 inches bigger on all sides than the area you will be covering. You can choose to overlap the sheets if you need more. Do your best to keep the sheeting snug against the soil for the best results.

This method also has the added benefit of killing any trapped pests or parasites. Plus, it will help the soil release more nutrients, making the ground very fertile to plant into when you are ready. While this method is best done in warmer weather, you can still do it in the colder months; just be prepared to leave the sheet on for a longer time.

Herbicides and Weed Killers

Spraying Herbicide on Plant
While we don’t recommend it, this is often a gardener’s last resort.

The final method we recommend to kill daylilies is using chemicals to get the job done. We recommend that you use this as a last resort, as this will definitely kill any other plants that may be next to the daylily infestation. Using herbicides can also kill other native plants, and harm pollinators in your area. So we do not recommend using it unless you have no other choice.

To start, apply a good, systemic weed killer carefully onto the infestation. Coat the top parts of the plant, taking care that the herbicide doesn’t seep into the ground. Understand that it is quite likely that other plants will die in the process.

Herbicides containing glyphosate have been proven to be effective against established daylily plants, which is definitely something you want. Application should be done on a calm day without wind or rain to prevent the spread of the herbicide as much as possible. Results may take up to two weeks, or even longer. If the plants still look healthy, reapply the herbicide until the plant eventually dies. Afterwards, dig up the remains of the plant and dispose of them properly.

Additional Removal Tips

Overgrown Flowers
The best way to prevent this flower from getting out of control is early prevention.

Now that you know how to kill the daylilies plaguing your garden, here are a few more tips to ensure that the plants do not come back. These plants can be very stubborn, and may take a few tries at removing them before they are truly gone. Let’s take a look at how to prevent that from happening.

Reminders for Disposal

Since daylilies are such hardy plants, it’s imperative that when you are disposing of plant matter, you do it in a way that will prevent regrowth. Do not mix them into compost, as they will simply create a new problem.

Improper disposal may even create headaches for other people, so do not simply throw them into the trash! Instead, place all pulled out/dug up parts of the daylilies into plastic bags and seal them very well. Ensure that the plastic is not something that degrades, and be responsible about disposal.

Stay Vigilant

Regardless of which removal method you’ve decided to use, to further ensure the success of your work, you must remain vigilant. Carefully look over the areas you’ve removed the daylilies from to determine if there is new growth. If there is, it will be easier to dig up the remaining plants. Repeat this process until no new growth can be seen. Once you’ve accomplished this, it will usually be okay to start planting new things in the soil again.

Thorough Mowing

When using a lawnmower or weed whacker to get rid of daylilies, it’s very important to be thorough in your mowing. Get as close to the ground as you can to remove as much of the growth as possible.

You know your tools best, so ensure that you’re always mowing at the correct settings. Run the mower or edge trimmer over the area even when you do not think that it needs it. This will give you better chances of success after you’ve finished the two-part mow and mulch process. Take care to dispose of all clippings properly, too!

Be Patient

Getting rid of daylilies can be a daunting task simply because those darned plants are just so stubborn! Since they’re resistant to many different inhospitable conditions, you can expect them to be around as long as you’re not taking measures to get rid of them.

Try out different methods, starting from the first ones we’ve listed. Then, simply stay the course and do not lose patience. Be persistent and consistent about your efforts to remove the plant, and these efforts will eventually bear fruit– and no more extra flowers!

A Note on Herbicides

We also thought we would reiterate that herbicides truly need to be a last resort before being used on daylilies. For one thing, they are very bad for the environment and may contaminate the area. When this happens, it can poison wildlife that come to eat the plants.

It can also render the soil infertile, making it unusable for any further planting. You will need to remove the affected soil and replace it, which can be a hassle. For this reason, we urge you to stick to more natural methods before trying out something so drastic.

Controlling Your Daylilies

Blooming Daylily
With many varieties to choose from, select one that is not as pervasive to add to your flower garden.

If you’ve read this article and found yourself wondering what you should do if you want to keep daylilies in your garden intentionally, then we have some advice for that too. After all, they produce truly stunning flowers and can be a delight to have in your garden. The key is to control their spread. Let’s see how you can do this.

Choose a Suitable Location

Plant in Full Sun
Plant them away from full sun to better control their growth.

As you may understand by now, daylilies require very little care to thrive and can spread even without active care. This is what makes control tricky. As such, think about the area where you will plant your daylilies. They thrive best in the full sun.

Since you want to control the spread of these plants, you should plant them somewhere they can get shade for most of the day. They will still be able to grow, but will not spread as rapidly. You can also consider planting them at the base of trees so they will have to compete with the thick, strong tree roots before spreading further.

Try a Border

Garden Border Fence
Using a garden border fence can help keep these plants contained.

You can purchase a border that can go around the area you will be planting your daylilies in. These borders sink into the ground and surround the daylilies, preventing growth beyond the border. You can find these borders at many garden supply stores, usually being marketed for bamboo plants. Once purchased, simply dig a trench around the area you will be planting your daylilies. Insert the border, overlapping the ends, and cover with soil. You should be set!

Use a Container

Yellow Flower in Pot
Daylilies are quite content to live in a pot.

If you really want to control the spread of daylilies, a more thorough approach would be to plant them in a container. Daylilies are actually quite suited to container life, though they will still need some room to spread to stay happy. You should use at least a gallon container to plant full-size daylilies in. However, you can opt to purchase smaller varieties to be placed in smaller pots.

Bear in mind that these plants will be thirstier than most other things growing in the soil of your garden; potted daylilies may need water once per day in the summer months. They will also need full sun to look their best, so give them at least 6 hours of sunlight daily.

Potted plants are also more susceptible to not making it through the winter. Thankfully, overwintering potted plants is as simple as keeping them in a heated room in your home. Once the harsh temperatures have subsided and the world springs back to life, bring your daylilies back out to enjoy them another year.

Pick the Right Variety

Purple Daylily Flower
Picking the right variety can help keep their rapid growth under control.

Lastly, when picking daylilies to grow in your garden, it’s imperative that you choose a good variety. This isn’t just about how the plant looks, either. While it’s certainly important that you choose a type of daylily that makes you happy, it’s to your whole garden’s benefit that you choose a variety that isn’t weedy.

There are cultivars of daylilies that have been grown so as not to have such a huge spread. To prevent further headaches, play it safe by picking a daylily variety that is known not to be problematic as it grows. There are many different daylilies, and they come in a variety of colors. You can find their flowers in red, and green as well.

Final Thoughts

We hope that this article has answered your questions on what you should do about daylilies in your garden. Understanding how they can turn rogue is important, but more so is knowing how to effectively get rid of them. Using the tips you’ve learned from this article, you should be able to handle getting rid of daylilies without much issue. Keeping them around can also be very rewarding, provided that you are willing to put in the work to keep them in check!

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