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Will Roundup kill lily of the valley?
Yes, Roundup will kill lily of the valley if applied correctly because it contains glyphosate, a non-selective herbicide that attacks most plants it touches.
Lily of the valley, though a tough and persistent ground cover, is susceptible to Roundup’s glyphosate-based action.
In this post, we will explore why Roundup will kill lily of the valley, how to apply it safely, and some alternative ways to manage lily of the valley without harming your entire garden.
Let’s get started.
Why Roundup Will Kill Lily of the Valley
Roundup will kill lily of the valley primarily because it contains glyphosate, a systemic herbicide, which gets absorbed by the leaves and moves down to the roots.
Here’s a closer look:
1. Glyphosate’s Broad-Spectrum Nature
Glyphosate, the active ingredient in Roundup, is a non-selective herbicide, which means it targets a wide range of plants including lilies of the valley.
It works by disrupting a plant’s ability to produce essential amino acids, eventually killing it.
Since lily of the valley is a broadleaf plant, it’s vulnerable to glyphosate.
2. Systemic Action Kills Underground Rhizomes
One of the reasons Roundup will kill lily of the valley effectively is because glyphosate is systemic.
Unlike contact herbicides that only damage the visible parts of a plant, glyphosate travels through the plant’s vascular system to reach underground rhizomes where lilies of the valley spread.
This ensures the roots and underground stems receive the herbicide, helping prevent regrowth.
3. Roundup Affects Both Leaves and Roots
Because lily of the valley grows from rhizomes beneath the soil, just spraying the leaves may not give a permanent kill.
However, glyphosate absorbed through leaves translocates to the roots and rhizomes, allowing Roundup to kill lily of the valley entirely over time.
4. Concentration and Repeated Applications Matter
Roundup will kill lily of the valley, but the concentration of glyphosate and how often it is applied influences success.
A thorough spray with the recommended concentration followed by repeat applications is often needed to fully kill this persistent plant.
This is because lily of the valley is resilient and can regrow if not eradicated completely.
How to Apply Roundup to Kill Lily of the Valley Safely
Using Roundup for lily of the valley requires care to avoid damaging nearby desirable plants.
Here’s how to apply it in a way that effectively kills lily of the valley without harming your garden:
1. Spot Treat Lily of the Valley Instead of Broad Spraying
To kill lily of the valley with Roundup while protecting other plants, spot treat by applying Roundup only to the leaves of lily of the valley.
Use a small brush or spray shield to control where the herbicide lands.
This targeted approach helps avoid killing adjacent plants.
2. Choose a Calm, Dry Day for Application
Wind and rain can cause Roundup to drift or wash away.
Applying Roundup in calm weather with no rain forecast helps glyphosate remain on the lily of the valley leaves long enough for absorption.
This maximizes its effectiveness in killing lily of the valley.
3. Use the Recommended Concentration of Roundup
Most Roundup products require dilution with water.
Follow the label instructions carefully to use the proper glyphosate concentration.
Using too weak a mixture may not kill lily of the valley, while too strong can increase the risk of runoff harming other plants.
4. Repeat Applications Are Often Necessary
Because lily of the valley is a tough perennial, one treatment of Roundup might not completely kill it.
Repeat applications every couple of weeks until no green growth appears help ensure thorough eradication.
5. Keep Pets and People Away During Treatment
When using Roundup to kill lily of the valley, it’s important to keep children and pets from the treated area until the spray dries.
This precaution avoids accidental exposure to glyphosate.
Alternative Methods to Kill or Control Lily of the Valley
If you’d prefer not to rely on Roundup or want to supplement herbicide use, here are some alternative ways to kill lily of the valley or keep it under control:
1. Manual Digging and Removal
One effective way to kill lily of the valley is to dig it out, carefully removing rhizomes.
This can be labor-intensive but works well if you don’t have a large infestation.
Dig deep enough to get all the underground parts or the plant will likely return.
2. Smothering With Mulch or Landscape Fabric
Lily of the valley dislikes being deprived of sunlight.
Covering the area with thick mulch or landscape fabric blocks light, suppressing the plant’s growth over time.
This method takes patience but can limit lily of the valley without chemicals.
3. Vinegar and Natural Herbicides
Natural herbicides containing acetic acid (vinegar) can burn lily of the valley’s leaves.
However, they do not kill the roots.
Repeated applications may weaken the plants, but vinegar isn’t as effective as Roundup in killing lily of the valley completely.
4. Solarization
Covering the soil with clear plastic during hot months traps solar heat, potentially killing lily of the valley roots.
This method takes several weeks but is chemical-free.
5. Landscape Redesign and Plant Competition
If you’re looking to manage lily of the valley rather than kill it outright, planting vigorous ground covers or shrubs nearby can outcompete it for nutrients and space.
This helps suppress lily of the valley’s spread naturally.
Precautions When Using Roundup to Kill Lily of the Valley
Using Roundup efficiently and safely to kill lily of the valley requires following important safety and environmental precautions:
1. Protect Desirable Plants Near Lily of the Valley
Roundup will kill most plants on contact, so shield or cover any nearby flowers, shrubs, or grass you want to keep.
Use cardboard or plastic barriers when spraying.
2. Avoid Herbicide Runoff Into Water Sources
Be cautious not to apply Roundup near ponds, streams, or storm drains.
Glyphosate can harm aquatic life if runoff occurs.
3. Wear Protective Clothing
When applying Roundup, wear gloves, long sleeves, eye protection, and a mask to avoid skin or eye contact and inhalation of the spray.
4. Follow Label Instructions Exactly
Manufacturer instructions explain how to mix and apply Roundup safely and effectively.
Adhering to these guidelines helps protect you, the environment, and increases your chances of killing lily of the valley with Roundup.
5. Consider Soil Health After Treatment
Glyphosate breaks down over time but may temporarily affect soil microbes.
Adding organic matter or compost post-treatment helps restore soil health after killing lily of the valley with Roundup.
So, Will Roundup Kill Lily of the Valley?
Roundup will kill lily of the valley because its glyphosate ingredient is a systemic herbicide that moves through the plant to destroy roots and rhizomes.
Applying Roundup properly by spot treating, using the recommended concentration, and repeating treatments increases the chance of completely killing lily of the valley.
However, because lily of the valley is tough and spreads underground, persistent follow-up is usually needed to prevent regrowth.
Alternatives like digging, smothering, or solarization can also help in controlling or killing lily of the valley if you want to avoid chemicals.
When using Roundup, be mindful of safety precautions to protect nearby plants, animals, and yourself.
Overall, if your goal is to kill lily of the valley effectively, Roundup is a reliable method when used carefully and consistently.
This knowledge will help you decide if Roundup is the right tool in your gardening arsenal for lily of the valley management.