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Pest SolutionsPESTS + WEEDSUSING PESTICIDES OR HERBICIDES?
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Bermuda Buttercup
Oxalis pes-caprae
Updated Oct 10, 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:
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.
LOOK-ALIKES: CREEPING WOODSORREL AND COMMON OXALIS
Species: Creeping woodsorrel
"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
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.
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
Mildly poisonous
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.
Prevent Bermuda buttercup
Diogo e Vitória Oliveira Pacheco, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
Look for Bermuda Buttercup Regrowth
Return to the site after control activities and look for regrowth. Bermuda buttercup regrows from underground bulbs and root fragments. Take action as needed.
Weston Miller, Oregon State University
Remove Dirt from Shoes and Equipment
- After working or traveling in a patch of Bermuda buttercup, clean your boots and tools. Use a wire brush to remove soil and seeds.
- If you drive through patches of Bermuda buttercup, clean your vehicle.
Weston Miller, Oregon State University
Install New Plants
- Take care of your plants to get them established and suppress Bermuda buttercup regrowth.
- Replanting stabilizes the soil surface, shades Bermuda buttercup seedlings, and creates habitat.
- A Bermuda buttercup infestation and removal activities may significantly damage a site. There may be few or no remaining desirable plants.
- Plan for at least 2-3 years of monitoring and maintenance.
- Your local Extension specialist, soil and water conservation district, or a professional re-vegetation specialist can suggest strategies for your area.
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.
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.
Jump to
| 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
|
A
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
|
| How much effort? | High effort
|
| 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.
Weston Miller, Oregon State University
B
Control with Herbicides
Chemical Method: Use with caution
iStock
Control with Herbicides
Use if Necessary
| Does it work? | Effective
|
| How much effort? | Moderate effort
|
| What's the risk? | Moderate risk
|
| Possible risk of exposure or harm from chemicals | El uso de herbicidas conlleva cierto grado de riesgo. El riesgo más bajo se presenta con el uso de métodos alternativos. You may be exposed to an herbicide if you:
Follow directions closely to reduce risk. |
Some herbicides 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.
Herbicide Application Tips
- These ingredients will damage most plants and grasses. Don”t let the spray contact plants you want to keep.
- 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.
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 for small print.
- 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).
NEED HELP?
The National Pesticide Information Center (NPIC) can answer questions about pest control chemicals.
1-800-858-7378 or npic@ace.orst.edu
Consider using a licensed pest or weed control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon and other states can suggest other methods.
Content provided by editor Weston Miller and writer J. Jeremiah Mann. Pesticide safety information edited by Kaci Buhl.
Peer review facilitated by OSU Department of Horticulture.
BERMUDA BUTTERCUP REFERENCES
Creeping Woodsorrel and Bermuda Buttercup
UC IPM
Buttercup Oxalis (Bermuda Buttercup) (PDF) - Weed Control In Natural Areas of the Western United States
Weed Research and information Center, University of California
Oxalis-pes-caprae
CAL IPC