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Bermuda Buttercup

Oxalis pes-caprae

Updated Apr 26, 2024

Make a Positive Identification

Bermuda buttercup is an invasive, spreading perennial plant with bright yellow flowers.
It is established in California, but not yet in Oregon or Washington. It is an invasive species of concern for mild-winter areas on the entire West Coast.
It forms dense patches. It crowds out other herbaceous plants in landscapes and natural areas.
Bermuda buttercup is difficult to remove due to its robust root system and bulbs.

Species: Bermuda buttercup

"Oxalis pes-caprae" by liesvanrompaey is licensed under CC BY 2.0

Bermuda buttercup's leaves are clover-like with 3 heart-shaped leaflets. They often have purple dots.

Species: Bermuda buttercup

"soursob (Oxalis pes-caprae)" by The Weed Forager's Handbook is licensed under CC BY-NC-SA 2.0

The leaves and stems of Bermuda buttercup grow from a loose base (rosette). Stems grow up to 14 inches tall. They carry bright yellow tubular flowers. The foliage dies and it goes dormant in the late summer.

Species: Bermuda buttercup

"Oxalis-pes-caprae-2019-01-01-IZE-015" by Zachi Evenor is licensed under CC BY 2.0

Bermuda buttercup's bright yellow flowers are 3/4 to 1.5 inches across. They have five petals. They occur in clusters on top of leafless stems growing 6 - 14 inches tall.

Species:

Small seedling rosette of clover-like leaves

Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org

Young Bermuda buttercup plants sprout clover-like leaves in a rosette.

Species: Bermuda buttercup

Daniel Feliciano, CC BY 2.0, via Wikimedia Commons

Bermuda buttercup spreads by creeping stems, both above- and below-ground, and by bulbs. New bulbs form underground along the creeping roots (rhizomes). Small, whitish bulblets form at the base of the leaves. It is not known to spread by seeds.

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LOOK-ALIKES: CREEPING WOODSORREL AND COMMON OXALIS

Species: Creeping woodsorrel

Creeping woodsorrel stems, leaves, flowers

"Oxalis pes-caprae in the city (for Wiki)" by Zachi Evenor is licensed under CC BY 2.0

Creeping woodsorrel (Oxalis corniculata) is a low-growing, spreading, perennial plant with yellow flowers. The leaves have 3 heart-shaped leaflets. The leaves and stems are sparsely hairy and are colored green to red-purple. Creeping woodsorrel spreads by creeping stems and seeds, while Bermuda buttercup spreads by bulbs and rhizomes. Both plants form dense patches. See How to Get Rid of Creeping woodsorrel.

Species: Common yellow oxalis

Common yellow woodsorrel stems, leaves, flowers, and fruit

James H. Miller & Ted Bodner, Southern Weed Science Society, Bugwood.org

Common yellow woodsorrel (Oxalis stricta) is native to North American. It is often considered a weed. It has yellow, five-petaled flowers on stems up to 9 inches tall. Unlike creeping woodsorrel and Bermuda buttercup, it doesn’t spread by creeping stems.

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Bermuda Buttercup Benefits

Bermuda buttercup is an invasive weed. It doesn’t have any benefits for people or the environment.

Bermuda Buttercup Risks

If left unmanaged, Bermuda buttercup forms a dense mat of stems and leaves. It smothers other garden and landscape plants. It can take over lawns. It is spreading into natural areas.
All parts of the plant contain oxalic acid. Eating large quantities of the plant is toxic to people and livestock.

Risk Card

Does it cause harm?

Adults & Children

Some

Property

High

Pets

None

Annoyance

High

Environment

High

Action Highly Recommended

Take Action

Bermuda buttercup has escaped from gardens and is spreading rapidly in some areas. It is taking over landscapes, sand dunes, and natural areas where it has been allowed to establish.

If you have Bermuda buttercup in your garden or on your property, take action to control its spread.

Do I need to take action?

Yes. Remove individual plants and small patches. Keep it from establishing on your property.
Report this invasive plant if found in Oregon or Washington.

What if I do nothing?

If left unmanaged, Bermuda buttercup forms a dense mat of stems and leaves.
It smothers other garden and landscape plants. It can take over lawns. It is spreading into natural areas.

NEED HELP?

Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon and other states can suggest other methods.

Solutions for Bermuda Buttercup

Early Detection and Rapid Response

Early identification and removal of Bermuda buttercup is important to prevent bigger problems.
Watch for Bermuda buttercup on your property. Take action to keep it from establishing.

Physical Removal of Plants and Non-Chemical Options

Cut Bermuda buttercup before it flowers and forms new bulbs. Repeat as needed to reduce a population.
Dig out plants. Sift soil and remove stem, roots, rhizomes, and bulbs.
Bermuda buttercup will regrow from roots, rhizomes, and bulbs that are left in the soil.
Dispose of all plant parts in the trash or landfill.

Herbicides (Weed Killers)

Herbicides effectively kill Bermuda buttercup when used according to the label instructions.

Monitoring and Follow-up

Following removal, return to the area every few months. Look for regrowth and seedlings. Take action as needed.
Established plants require several years of follow-up control actions.

Method	Does it work?	Is it safe?	Recommendation
A Physically Remove Plants	Effective	Low risk	Recommended
B Control with Herbicides	Effective	Moderate risk	Use if Necessary
C If Using Herbicides, Protect Yourself & Minimize Risks
D Prevent Bermuda buttercup

Physically Remove Plants

Non-Chemical Method

Joseph M. DiTomaso, University of California - Davis, Bugwood.org

Physically Remove Plants

Recommended

Hand pull and dig plants when the soil is moist. Dig and sift the bulbs from the soil.
Mowing will reduce patch vigor and require follow-up control activities.

Does it work?	Effective It’s challenging to remove all the root pieces from the soil. Expect it to regrow. Use preventive measures for best results.
How much effort?	High effort Hand pull and dig plants when the soil is moist. Dig and sift the bulbs from the soil. Dispose of plants in sturdy plastic bags in the trash or landfill.
What's the risk?	Low risk
Possible risk of exposure or harm from chemicals	NONE

Tips for Removing BERMUDA Buttercup

When you dig up plants with hand tools remove as much of the root, rhizomes, and bulbs as possible.
Expect regrowth.
It is easiest to remove Bermuda buttercup plants during fall through spring. The soil is moist and leaves are present.

Soil Disturbance and Erosion

Minimize soil disturbance as much as possible when removing Bermuda buttercup.
Regrade the soil after digging roots. Apply mulch (when appropriate).
Take steps to prevent erosion as needed.
Replant the area to shade Bermuda buttercup seedlings.

Sealable plastic bag next to trash can with note “invasive plant, do not compost”

Weston Miller, Oregon State University

Put all Bermuda buttercup plant material in a plastic bag labeled "invasive plant, do not compost." Put the bagged material into the trash. Or take it to a landfill for disposal.
Don't compost Bermuda buttercup on your property. It will regrow if bulbs are accidentally replanted.

You can also kill roots and bulbs by exposing them to direct sun for many months before composting them.

Control with Herbicides

Chemical Method: Use with caution

iStock

Control with Herbicides

Use if Necessary

Does it work?	Effective It requires several years of monitoring and effort to get rid of Bermuda buttercup. Use preventive measures for best results.
How much effort?	Moderate effort Treat individual Bermuda buttercup plants and patches. Return to the area each year and take action as needed.
What's the risk?	Moderate risk Herbicides come with real risks. ALWAYS read the entire label front to back. Review instructions even for brands you know. Herbicides can run off your site into waterways and may harm wildlife. See How to Keep Pesticides Out of Waterways.
Possible risk of exposure or harm from chemicals	Using herbicides includes some amount of risk. The lowest risk comes with using alternative methods. You may be exposed to an herbicide if you: Get it on your skin Breathe it in Eat or smoke afterward without washing hands Touch or eat plants that are wet with spray (you, pets, or children) Bring it inside on your shoes or clothes Follow directions closely to reduce risk.

Some products are available for home use. These products, used individually or in a mixture, are effective chemical treatments for Bermuda buttercup. Look for these chemical names in the “Active Ingredients” section of product labels.

Glyphosate
Triclopyr
Glufosinate

Suggested pesticides are permitted for HOME use in Oregon. Read the label for application directions and effectiveness information.

ONLY professional pesticide applicators can use Restricted-Use Pesticides (RUP) that may be more effective. For larger stands of Bermuda buttercup contact a licensed pesticide applicator with experience controlling Bermuda buttercup.

Example label with active ingredient glyphosate

PICOL

Sample product label with Active Ingredient highlighted

A red box on the example label highlights active ingredient glyphosate. The text on the label states “Kills grass and weeds...”.

Herbicide Application Tips

Apply herbicide to Bermuda buttercup when it is actively growing in winter and early spring.
Expect that Bermuda buttercup will regrow after treatment with herbicides. Look for regrowth and re-treat as needed.
These ingredients will damage most plants and grasses. Don”t let the spray contact plants you want to keep.

If Using Herbicides, Protect Yourself & Minimize Risks

Chemical Method: Use with Caution

FangXiaNuo, iStock

Why is it important to read herbicide labels?

They have detailed information on how to use the product correctly and legally.
They contain information on potential hazards of the product.
They provide instructions you should follow for poisonings and spills.
Following label instructions helps you to minimize the risks and maximize the benefits.

Key Herbicide Safety Tips

Read the entire label front to back.
Follow the instructions.
Review the instructions even for brands you know.
Only apply the product where the label says it may be applied.
Be precise in your application. More is not better.

The Label is the Law

ALWAYS read the label before using herbicide products. The label is a legal document that provides information on how to safely use the herbicide. This helps avoid harm to human health and the environment. Using an herbicide in off-label ways is illegal. It can result in legal enforcement actions.

READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.

Labels are different for every product and they often change over time.
Use a magnifying glass if needed.
Pay attention to CAUTION, WARNING, and DANGER statements.
Pay attention to the PRECAUTIONARY STATEMENTS.
The law states you must read and follow herbicide instructions.

Protect Yourself
Eye, skin & lung irritants

Wear the right protective gear. This often includes chemical-resistant gloves, safety glasses, a long-sleeve shirt, pants, socks, and shoes.
Mix outdoors or in a well-ventilated area.
Wash hands after mixing or applying, and before eating or smoking.
Take a shower immediately after handling herbicides.
Wash clothes worn while mixing or applying separately from other laundry.

Protect Children & Pets
Children and pets are at risk if they eat or touch the plants before it dries.

Keep them away during and after applying herbicides (read label for how long).
Remove toys and pet dishes from yard before applying.
Don’t track herbicide products into your home on shoes or clothes.

Protect Pollinators

Apply in the early morning or evening when bees are less active.
Kill weeds before they flower. Avoid spraying flowering plants.
Do not spray on bees or insects.

Protect Plants You Want to Keep

Glyphosate and similar herbicide ingredients damage both grass and broadleaf plants.
Minimize spraying of foliage, stems, exposed roots, or the trunks of desirable shrubs or trees to avoid harm.
Follow the label to avoid damaging the roots of trees and shrubs.

Avoid Wet, Windy, or Hot Weather
Use during favorable weather for best results.

Don’t spray when it’s raining or when rain is expected in the next 24 hours.
Wind causes spray to drift that can get on you and desired plants.
Herbicides may be less effective in hot weather if the target plants are moisture-stressed.
Some herbicides can turn into a vapor in hot weather and damage nearby plants.

Don’t Spray into Water

It’s illegal to apply herbicides in a stream or slow moving/wetland pool.
You need a product registered for aquatic areas. This includes waterways, ditches, drains, and other places where water collects.

Storage & Disposal

Store in a secure area away from children.
Don’t put unused herbicide products in the trash.
Never pour down any drain or waterway.
Take unused herbicides to a hazardous waste facility.

Call 1-800-CLEANUP (1-800-253-2687) to find out where to dispose of herbicides.

For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call 503-234-3000, email or visit Metro’s website

More about:

About Using Pesticides on School Grounds in Oregon

If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management (Oregon Department of Agriculture).