If shamrock-shaped leaves and yellow flowers are creeping through your lawn, you’re under attack from oxalis weeds. This stubborn invader spreads like wildfire, choking out grass and destroying your landscape. Don’t surrender just yet – you can win the war on oxalis using the right tactics at the right time. Arm yourself with the ultimate battle plan by following these 5 proven tips to banish creeping oxalis from your yard for good. Say goodbye to shamrocks with robust grass that’s oxalis-free!

What is Creeping Oxalis?

Creeping oxalis, also known by its scientific name Oxalis corniculata, is a problematic weed that can quickly take over lawns and gardens. This aggressive plant is easily identified by its distinctive shamrock-shaped leaves and bright yellow flowers.

Appearance and Growth

Oxalis has delicate, light green, clover-like leaves made up of three heart-shaped leaflets. These trefoil leaves grow in an alternating pattern along slender creeping stems that can reach up to 12 inches long. The stems root at the nodes as they spread horizontally across the ground, allowing the plant to form dense patches.

The flowers have five yellow petals and bloom from early spring through fall. When seed pods mature, they explode to disperse seeds up to several feet away. This enables the plant to propagate rapidly. In mild climates, oxalis grows year-round. It tends to thrive in shady, moist areas but can tolerate full sun and a variety of soil types.

Oxalis can be identified by its shamrock-shaped leaves. (Source: Gardening Know How)

While considered an annual weed in cold climates, oxalis behaves as a perennial in warm regions, returning year after year once established. It spreads not only by seed but also via bulblets that form on the roots. Disturbing the soil causes these bulblets to detach, resulting in further dispersal.

Why So Invasive?

What makes creeping oxalis such a challenging weed is its remarkable ability to reproduce from multiple sources. A single plant can produce hundreds of seeds as well as underground bulbs and bulbils. Just a tiny piece of stem or root left behind can give rise to a whole new infestation.

On top of its reproductive prowess, oxalis has a rapid growth rate. Its foliage quickly carpets open areas of soil before grass or other plants can take hold. Certain species have even developed herbicide resistance, making chemical control difficult.

Look-Alikes

Oxalis is most often confused with clover, as both have triple leaflets. However, clover leaves are oval-shaped, not heart-shaped, and clover produces rounded flower heads rather than five-petaled yellow blooms. Wood sorrel is another common name for oxalis, but true sorrel (Rumex species) is a separate plant.

The key identifiers are the distinctly heart-shaped, shamrock-like foliage and bursting yellow flowers. If you spot these signs, you likely have creeping oxalis on your hands! Prompt control measures are advised before the infestation gets out of hand.

Why Get Rid of Oxalis in Lawns?

Creeping oxalis is considered a pesky weed by most lawn owners. At first glance, its delicate foliage and yellow blooms can seem harmless. However, left unchecked, oxalis can quickly become a stubborn problem in home lawns. Here’s an overview of the key issues caused by oxalis infestations and why it’s advisable to control them.

Outcompetes Grass

Given favorable conditions, oxalis grows rapidly and spreads across bare patches of soil. Its low-growing, dense mats crowd out surrounding grass plants by blocking their access to sunlight. Oxalis leaves even release chemicals that inhibit the germination and growth of nearby plants.

Over time, the expanding oxalis crowds out more and more grass. This worsens as mowing causes any remaining grass to weaken and thin out even more. Soon large sections of lawn can transform into pure oxalis. Re-establishing healthy grass then becomes an uphill battle.

Spreads Aggressively

Oxalis is excellent at proliferation. A single plant can produce up to 800 seeds per year. Its delicate stems root easily at the nodes, enabling the plant to creep steadily outward. Bulbs and bulblets form underground, detached by any disturbance and spreading the infestation.

Within one season, a couple oxalis plants can multiply to blanket entire garden beds or lawns. The plant thrives year-round in warm climates. Its rapid horizontal spread combined with prolific seed production make oxalis a swift invader.

Ruins Lawn Uniformity

For homeowners seeking a lush, green, uniform lawn, oxalis sticking out like a sore thumb poses an issue. Its light green, low-growing foliage contrasts sharply with surrounding grass. The explosion of bright yellow flowers in spring and summer only worsens the clash.

Oxalis often pops up in circular patches, creating visible unevenness in the lawn. Its ability to spread rapidly means these unsightly patches can enlarge and multiply quickly. The plant’s perennial nature means it will return year after year too.

Harbors Other Pests

The dense, low-growing mats of oxalis provide the perfect hideout for other lawn pests. Slugs and snails thrive in moist shady oxalis patches. The flowers attract aphids. Oxalis debris also makes an ideal environment for disease organisms like fungus and bacteria to grow.

Getting rid of oxalis removes these pest-friendly habitats. It also opens up the area to sunlight and airflow, making the environment less hospitable to other weeds. A uniform grass cover is less prone to invasion than bare, oxalis-covered soil.

Hard to Control

Oxalis is notoriously difficult to eradicate. Hand weeding often worsens the problem by spreading bulblets. Selective herbicides that won’t harm lawn grass are iffy at best. Pre-emergents don’t stop the spread of existing plants.

Once oxalis has established itself, it’s resilient against control attempts. The weed quickly bounces back from damage via its numerous reproductive avenues. For this reason, early intervention is key before infestations get out of hand.

Hurts Lawn Health

Heavy oxalis growth deprives grass plants of light, space, nutrients and water. It also causes thinning by blocking grass growth, which opens the door to more weeds. Oxalis debris left on the lawn can contribute to thatch buildup and moisture issues.

By disrupting the lawn ecosystem, oxalis creates conditions favorable to itself but detrimental to healthy grass. Getting rid of oxalis removes this competition factor and improves growing conditions for the desired grass.

Ruins Other Garden Beds

While lawns are its favorite spot, oxalis can also wreak havoc in flower and vegetable gardens. It establishes most readily in open, sunny beds amended with rich organic matter – the same conditions many plants thrive in.

Low-growing oxalis can quickly engulf shallow-rooted seedlings before they have a chance to mature. Trying to hand weed damages crop plants in the process. For gardeners, preventing oxalis from taking hold in the first place is critical.

Sap Nutrients and Moisture

As a rapid grower, oxalis efficiently extracts available nutrients from the soil. Its dense mats also monopolize soil moisture. This starves surrounding plants, reducing their vigor and making them less able to compete.

In flower beds, oxalis pulls nutrients and moisture away from desired ornamentals. Vegetable plants become less productive due to the water and mineral competition from oxalis. Removing it improves growing conditions for other plants.

Spreads to Native Areas

Some oxalis species have become serious invasive plants in natural settings. For example, creeping wood sorrel is considered a noxious weed in many states. It has displaced native plants in fields and forests.

Preventing oxalis from escaping out of managed lawns and gardens is important to avoid contributing to invasions in natural areas. Birds can disperse seeds from yards into wild areas, allowing oxalis to spread with detrimental impacts.

Tip 1 – Hand Pull Small Infestations

For minor oxalis invasions, manually removing the weeds by hand can be an effective control method. When done properly, hand pulling eliminates the entire plant including the roots. This prevents regrowth. However, certain precautions are necessary to avoid making the problem worse.

When Hand Pulling Works

Hand weeding oxalis is only practical for small infestations. If you spot just a few sprigs popping up in your lawn or garden bed, quickly pulling them up can halt the invasion. This eco-friendly solution causes minimal disturbance to surrounding plants compared to other control methods.

Target young oxalis plants as soon as you observe them. Immature weeds are easiest to pull completely since the root system is less developed. Focus on removing all plants before they start flowering and producing seeds for further dispersal.

Hand pulling is also useful for maintenance weeding if you stay on top of the task. Periodically check for any new oxalis growth and remove it before it gets established. Be diligent about weeding after any soil disruption that might have spread bulblets.

Manual Removal Technique

Proper technique is crucial when hand pulling oxalis to avoid spreading it further:

1. Use a weeding tool like a trowel or hori-hori knife to loosen the soil and dig down at least 2 inches around each plant. Try to extract as much of the roots as possible.
2. Grasp the base of the plant near the soil and gently wiggle back and forth while pulling upward to extract the entire plant including all the roots and bulblets.
3. Seal any detached bulblets or fragments in a plastic bag and dispose of them in the garbage, not the compost pile. Rinse tools afterwards to remove any remaining bulblets.
4. Check the area regularly for any resprouts and remove them promptly. Oxalis begins flowering 6-8 weeks after germinating so don’t allow new growth to linger.

Avoid Spreading Bulbils

The main risk with hand pulling is that the underground bulbs and bulbils will easily detach and be left behind. Any small fragment has the potential to give rise to a new oxalis plant. Violently ripping plants out causes more breakage of these reproductive structures.

Gently loosen and lift instead of pulling hard. Try to keep as much of the root system intact as possible when extracting each weed. Removing plants before bulbils have developed helps reduce inadvertent spread. Be sure to dispose of any bulblets that come loose during weeding.

Persistence Is Key

After the initial weeding, oxalis will likely resprout from any remnants left in the soil. Repeat the manual removal process promptly whenever new growth appears. This must be done continually to deplete the reserves stored in the remaining bulbs.

Over time, consistent hand weeding can eventually eradicate a small oxalis infestation, but it requires persistence. Once the weed is widespread, manual control becomes infeasible. For larger infestations, turn to selective herbicides instead.

Supplement with Prevention

To assist the hand weeding efforts, also adopt good prevention practices:

• Maintain a dense, vigorous lawn through proper mowing, fertilizing, irrigation and pH management. This minimizes bare spots for oxalis to invade.
• Quickly repair any damaged areas that could provide entry points for oxalis.
• Apply corn gluten meal in early spring to inhibit germination of oxalis seeds.
• Use a pre-emergent herbicide like pendimethalin early in the growing season to block growth of young oxalis plants.
• Avoid excessive soil disturbance that could spread bulblets.
• Monitor regularly for new oxalis growth. Remove immediately before it can reproduce.

With diligence and persistence, hand weeding combined with preventative lawn care can control limited oxalis infestations. But for heavy invasions, a selective herbicide solution will be necessary.

Tip 2 – Use a Selective Herbicide

For moderate or severe oxalis infestations, selective herbicides provide an effective chemical control option. Unlike non-selective weed killers, selective herbicides target broadleaf weeds but won’t harm surrounding grass plants. For lawns overrun with oxalis, a selective herbicide can tackle the problem without damaging the turf.

Choosing the Right Herbicide

Look for a selective herbicide containing the active ingredients mecoprop, dichlorprop, or triclopyr. Some examples are:

• MCPP – Available under brand names like Mecomec and Mallet. Provides moderate control of oxalis.
• Trimec – Contains a mix of 2,4-D, dicamba and mecoprop for better broadleaf weed control.
• MSM Turf – Includes metsulfuron-methyl as the primary active weedkiller. Specifically targets oxalis and other tough broadleaf weeds.
• Weed-B-Gon – A retail product with dicamba and 2,4-D as active ingredients. Works on various lawn weeds.

Always check the product label to verify oxalis is listed and the herbicide is approved for use on your grass type. Stick to the recommended application rate as well.

How to Apply

Selective herbicides are commonly sold as ready-to-use liquids, concentrates that must be diluted with water, or granular products. Follow the label instructions to properly mix and apply the right amount of herbicide evenly across the affected area.

Spray applications tend to provide the best results:

• Use a pump spray tank or backpack sprayer to evenly cover oxalis leaves with herbicide solution.
• Set the nozzle to produce a fine spray for uniform coverage. Avoid runoff onto desirable plants.
• Adding a surfactant improves leaf absorption of the herbicide.
• Granular products can be spread with a broadcast spreader then watered in to activate.

When to Apply

Timing is key when using selective herbicides for maximum effectiveness on oxalis:

• Treat in early spring right after new growth begins. Oxalis is most vulnerable at the start of the growing season before going into seed production.
• Warm temperatures above 60°F allow for better herbicide uptake through the leaves. Avoid applying during cold snaps.
• Do not use these herbicides during summer heat stress or just before lawn grass goes dormant in fall. This could damage the desired turf.
• 2-3 applications per year, spaced 3-5 weeks apart, provides the best control of oxalis.

What to Expect

• Symptoms begin as yellowing or reddening of the oxalis foliage within 3-7 days after spraying.
• Complete browning and dieback of the weeds typically occurs 2-4 weeks post-application.
• Removal of dead debris prevents it from accumulating and blocking sunlight from reaching grass plants.
• In severe infestations, repeat applications may be needed over a period of years to fully eradicate oxalis. Be patient and persistent.

Avoiding Injury to Lawns

While selective herbicides are designed to control broadleaf weeds without harming grass, injury can still occur if improperly applied:

• Excessive rates can damage grass, especially during hot, dry conditions. Never exceed the label rate.
• Granules that get concentrated in one area can burn grass. Apply evenly and water in thoroughly after applying.
• Avoid spray drift contacting desired plants. Use coarse spray settings and spray on calm days.
• Do not apply to new sod or seeded lawns until well established, typically after two mowings.

Following all label precautions prevents injury so that the herbicide effectively kills only the weeds. Though not a quick fix, herbicides provide a viable chemical option for gaining control of extensive oxalis infestations when part of an integrated strategy. Let me know if you need any clarification or have additional suggestions for improving this section!

Tip 3 – Apply a Pre-Emergent Herbicide

Pre-emergent herbicides provide a proactive way to prevent oxalis infestations in your lawn. Unlike selective herbicides that kill existing weeds, pre-emergents use chemicals to block new seeds from germinating. For annual oxalis, this can be an effective preventative strategy.

How Pre-Emergents Work

Pre-emergent herbicides create a chemical barrier just below the soil surface. As weed seeds begin to germinate and start growing roots down into the soil, they absorb the herbicide. This then kills the young seedling before it has a chance to emerge and establish.

However, pre-emergents have no effect on mature weeds that are already up and growing. They strictly act as a preventative control measure against new weed seeds sprouting. This makes them ideal for preventing large flushes of annual weeds like oxalis.

Using Pre-Emergents for Oxalis Control

There are several pre-emergent active ingredients to look for on herbicide product labels:

• Prodiamine – Found in products like Barricade and prevents development of roots in germinating seeds. Must be applied prior to oxalis germination.
• Pendimethalin – The active ingredient in Scotts Halts. Creates a chemical layer near the soil surface. Apply early in spring before oxalis growth.
• Dithiopyr – Sold as Dimension and acts by inhibiting cell division in emerging shoots. Best applied in fall before winter oxalis germination.

Application Tips:

• Read the label to determine the correct rate based on your lawn size. Do not overlap or over apply.
• Time applications for early spring, fall, or both depending on the pre-emergent used. This coincides with peak oxalis seed germination periods.
• Water in after application to activate the herbicide and create a uniform chemical barrier in the top layer of soil.
• Avoid disturbing the soil after applying or it can break the chemical barrier. Leave treated areas undisturbed for 3-6 months.

Limitations of Pre-Emergents

While pre-emergent herbicides can prevent new oxalis growth, they do not control existing plants or new growth arising from underground bulbs and bulbils. For this reason, a standalone pre-emergent application rarely eradicates established oxalis infestations.

However, combining pre-emergent use with selective herbicides, manual weeding, and proper lawn care provides a synergistic approach for gaining control of oxalis. The pre-emergent prevents new seedlings while other methods target established plants. Used together, these tactics provide a one-two punch against this stubborn weed.

Tip 4 – Promote Healthy, Dense Lawn

The best defense against oxalis invasion is a good offense in the form of a thick, vigorous lawn. Weeds like oxalis thrive in thin, sparse grass that allows bare soil easy access to sunlight. By maintaining optimal growing conditions, you can help grass outcompete and prevent oxalis from establishing in the first place.

Mowing Tips

Proper mowing practices encourage dense, tight growth:

• Increase cutting height during summer heat and other stresses to help grass conserve resources and recover better.
• Never cut off more than 1/3 of the grass blade length per mowing session. Scalping causes thinning.
• Use sharp mower blades to avoid shredding leaf tips, which can open the grass up to disease.
• Change mowing patterns periodically to prevent soil compaction and rutting.
• Leave grass clippings in place to return nitrogen and organic matter back to the soil.

Adequate Irrigation

Oxalis thrives in dry conditions and bare, cracked soil. Prevent this with appropriate lawn watering:

• Schedule deep soaking 2-3 times per week to moisten the root zone of grass plants.
• Early morning is the best time to water to minimize evaporation loss.
• Adjust schedule based on weather, avoiding watering just before or after heavy rain.
• Use tuna can tests to gauge sprinkler coverage and identify dry spots needing more run time.
• Let grass dry slightly between watering without allowing drought stress.
• Improve irrigation efficiency with scheduled soak and cycle times.

Regular Fertilization

Applying fertilizer on a seasonal basis provides balanced nutrition to fuel vigorous growth:

• Use a complete N-P-K turf fertilizer with micronutrients 4 times per year.
• Organic fertilizers like milorganite release slowly over time. Mineral fertilizers are faster acting.
• In fall, use low nitrogen, high potassium formulas to prepare grass for winter.
• Alternate between quickly absorbed foliar feeds and longer lasting granular products.
• Avoid excessive nitrogen levels that create succulent grass prone to disease.
• Test soil periodically to determine specific nutrient needs.

pH Adjustment

Extremes of overly acidic or alkaline pH can limit nutrient availability.

• Test lawn soil pH annually and adjust according to grass type target levels.
• Lower pH with applications of elemental sulfur for alkaline western soils.
• Raise pH in acidic eastern soils by applying pelletized limestone.
• Improve very acidic soil with calcitic lime for a long-term adjustment.
• Recheck pH after a few months to determine if further amendments are required.

Aeration and Dethatching

These mechanical practices promote healthy soil structure:

• Core aerate lawns annually using a plug aerator to improve airflow and drainage through the root zone.
• Dethatch in early fall if thatch exceeds 1/2 inch, using a power rake or vertical mower to remove debris buildup.
• Topdress bare areas after aeration or dethatching using a thin layer of quality compost to reintroduce organic matter.

The best defense against oxalis invasion is to create soil and growing conditions that favor dense, resilient grass plants that can out-compete weeds. A healthy lawn ecosystem provides few opportunities for oxalis to sneak in! Please let me know if you would like me to expand or modify this section in any way.

Tip 5 – Solarize Infested Areas

For stubborn oxalis patches that resist other control methods, solarization is an eco-friendly option. This technique uses heat from the sun to “cook” weed seeds and rhizomes in the soil. When done properly, solarizing can eliminate oxalis without chemicals. However, it also harms desirable grass, so only use it for spot treating small areas.

How Solarizing Works

Solarization involves covering infested soil with clear plastic sheeting during hot, sunny weather. The plastic traps radiant heat from the sun and causes temperatures in the upper inch of soil to rise significantly.

Over 4-6 weeks, the zone under the plastic can reach temperatures as high as 140°F. This heat kills weed seeds, fungi, insects, and vegetable parts like oxalis bulbs and rhizomes. However, it also damages beneficial organisms and leaves the soil temporarily sterile after treatment.

When to Solarize

For best results, solarize during the hottest part of summer when soil temperatures will be elevated for prolonged periods.

• Time applications for early to mid summer when daily highs exceed 85°F.
• Maximize sun exposure by solarizing beds oriented south to southwest.
• Remove any plants or residue from the area prior to covering with plastic.
• Leave plastic in place for 4-6 weeks throughout the hottest weather.
• Irrigate soil 2-3 days before covering to aid heating. Do not water again until finished.

How to Solarize Effectively

Follow these steps for proper solarization technique:

1. Mow grass very short or kill it completely if solarizing a lawn area.
2. Install plastic edging 3-6 inches deep around the perimeter to hold the cover flush with the soil.
3. Water the area well then cover immediately with clear polyethylene plastic sheeting, burying all edges.
4. Weigh down the center of the plastic if necessary to keep it tight to the ground.
5. Maintain the plastic barrier with no openings for 4-6 weeks through intense heat.
6. Remove plastic once soil temperatures start declining in late summer or fall.
7. Rake up any dead grass or weed residue after solarizing.
8. Reseed treated areas of lawn to restore grass cover if desired.

Effectiveness on Oxalis

The heat from solarizing reliably kills oxalis seeds and bulbs in the top few inches of soil. However, plants can still resprout from deeper roots and bulbs that survive. For this reason, solarization controls but may not fully eradicate established oxalis.

It is most effective on annual oxalis that regenerates solely from seed. Repeated solarizing for 2-3 consecutive seasons provides the best results on severe infestations. For spot treating small areas of lawn, solarization can be a chemical-free oxalis control option.

When to Seek Professional Help

Despite your best efforts, sometimes oxalis reaches a point where DIY control is no longer effective. If you’ve tried the tips discussed but the weed still persists and spreads, it may be time to bring in a professional. Here are signs it’s time to call for backup and the benefits of hiring experts.

Indicators DIY Methods Have Failed

• Oxalis covers over 50% of your lawn or garden bed area.
• Infestations worsen noticeably from one year to the next.
• Weeds are spreading into new areas of the landscape.
• Hand pulling and herbicides provide only temporary suppression.
• Lawn thinning is accelerating as oxalis displaces grass.
• Turf is severely infested despite preventative efforts.

If you find yourself in an endless battle against ever-increasing oxalis, with little progress despite multiple control tactics, consider getting professional help.

Why Extermination Services Are Effective

Reputable lawn care companies and exterminators have access to certain oxalis treatment options and strengths of chemicals not available to regular homeowners. Professionals can use:

• Concentrated selective herbicides approved for licensed applicators.
• Powerful pre-emergents for lasting residual weed prevention.
• Combination mixes of multiple oxalis-fighting active ingredients.
• Commercial-grade spray equipment for optimal herbicide coverage.

They also have extensive experience devising customized, multi-pronged strategies to tackle especially stubborn oxalis infestations. A coordinated professional attack is sometimes the only way to gain the upper hand against a widespread oxalis invasion.

Added Value of Pro Services

On top of superior weed control, professionals provide additional value:

• Skilled technicians properly identify oxalis and diagnose the extent of infestation.
• Companies use the latest, EPA-approved control products and advanced application techniques.
• They determine the optimal timing for treatments based on plant life cycles.
• Technicians take safety precautions when handling chemicals.
• Equipment allows precise calibration and dosing of herbicides.
• The work is guaranteed, with follow-up treatments included if needed.

This level of skill and service is hard for homeowners to match on their own. Plus professionals save you valuable time!

Questions to Ask Prospective Companies

Once you decide to hire a service for oxalis control, do your research:

• Are they licensed in your state to apply pesticides?
• Do they have specific experience with oxalis treatment?
• What methods and products will they use?
• How soon will you see results?
• How often will they need to service the property?
• What guarantees or warranties do they offer?
• What safety measures will they take during applications?

A trustworthy company will readily answer any questions you ask upfront. Investing in professional elimination of severe oxalis can get your lawn back on track when DIY options fail. Let me know if you would like me to expand on any part of this section or have additional details to incorporate.

Frequently Asked Questions

If you’re struggling to control oxalis, chances are you have some lingering questions. Here are answers to some of the most common oxalis FAQs to help you win the battle against this persistent weed.

How long does it take for oxalis to die after herbicide treatment?

You should begin seeing effects within 3-7 days after spraying as the oxalis foliage yellows and withers. However, it typically takes 2-4 weeks for the weeds to completely brown out and deteriorate following treatment. Be patient, as quick results are unlikely with oxalis.

Will oxalis come back after using a selective herbicide?

Unfortunately, yes. Due to its extensive underground bulb and rhizome system, oxalis commonly resprouts even after herbicide treatment. Multiple applications are often needed over a couple years to fully eradicate an established infestation. Expect to respray emerging oxalis.

When is the best time to treat oxalis chemically?

Early spring when new growth first emerges is ideal, as young plants readily absorb the herbicide. Temperatures should exceed 60°F for optimal uptake. Avoid treating during summer heat or near grass dormancy in fall to prevent lawn injury.

How can I get rid of oxalis organically without chemicals?

Vinegar, boiling water, or high heat from flame weeding provide non-chemical options for spot treating oxalis. Maintaining thick lawn cover also discourages oxalis naturally. For severe infestations, however, an organic approach may not be realistic.

Does oxalis spread if mowed over?

Yes, mowing spreads oxalis by dispersing cut fragments that can take root elsewhere. Always bag and dispose of clippings from oxalis-infested lawns instead of mulching. Mowing also weakens grass and creates open soil perfect for oxalis invasion.

How do you stop oxalis from spreading?

Improve lawn density, hand weed immediately upon seeing new growth, apply pre-emergent herbicides, avoid soil disturbance that spreads bulbs, and don’t mow over plants. Solarizing small areas also creates oxalis-free zones. Stopping initial spread is key before infestations enlarge.

Will 2,4-D or Weed-B-Gon kill oxalis?

These broadleaf herbicides containing 2,4-D and dicamba provide moderate control of oxalis. For best effect, use a product containing triclopyr or metsulfuron-methyl. 2 applications of Weed-B-Gon spaced 3 weeks apart in spring can help suppress oxalis.

Is oxalis annual or perennial?

Oxalis behaves as a perennial weed in warm climates, returning yearly from underground bulbs. In cooler zones, it acts more as a prolific summer annual, dying back each winter but reseeding freely. Different control tactics target each behavior.

Should oxalis be pulled out?

Hand pulling small invasions can eliminate oxalis, but avoid ripping plants out which can spread bulblets. Carefully dig around clumps and gently lift to remove all roots and bulbs intact. Discard any detached pieces to prevent re-rooting.

Summary

Dealing with a creeping oxalis infestation can be an exercise in frustration, but using the right control strategy pays off. Manually removing small patches, applying selective herbicides, preventing new growth with pre-emergents, nurturing a healthy lawn, and spot solarizing were covered as proven tactics. While eradicating established oxalis takes persistence, you now have several effective options to add to your weed management plan. Employing two or more of these methods in a coordinated attack will help gain control of stubborn oxalis. With patience and diligence, you can reclaim your lawn and garden from this invasive weed.

Key Takeaways

• Oxalis is an aggressive weed that can quickly take over lawns and gardens with its fast growth and prolific seed and bulbil production.
• Getting rid of oxalis as soon as it appears is critical before infestations get out of control.
• Hand pulling small patches can eliminate young plants but must be done carefully to remove all bulbils and roots.
• Selective herbicides provide chemical control for large infestations but require repeat applications for full eradication.
• Pre-emergent herbicides offer a preventative approach by blocking weed seeds from sprouting.
• Promoting a dense, healthy lawn is key to preventing oxalis from invading bare spots and thinning turf.
• Solarization effectively uses radiant heat to weaken and kill oxalis bulbs and seeds in treated areas.
• Combining methods like mowing adjustments, herbicides, pre-emergents and lawn fertilization provides the best control.
• Seek professional help for severe infestations that continue spreading aggressively despite using multiple DIY tactics.

Frequently Asked Questions

Q: How can I tell the difference between oxalis and clover?

A: Clover has oval-shaped leaflets rather than shamrock-shaped ones like oxalis. Clover also produces rounded flower heads, not yellow 5-petaled flowers.

Q: Will pre-emergent herbicides kill existing oxalis plants?

A: No, pre-emergents only prevent new seeds from sprouting. Use selective herbicides or hand weeding to remove oxalis already growing.

Q: How soon after spraying will the oxalis start dying?

A: You’ll see yellowing and withering of foliage within 3-7 days but it takes 2-4 weeks for complete browning and dieback.

Q: Should I dig up oxalis roots or just spray leaves?

A: Spraying is more effective since digging can spread bulbils. Herbicides translocate down to the roots.

Q: How can I get rid of oxalis organically without chemicals?

A: Boiling water, vinegar, or flame weeding provide organic options but may not be practical for large infestations.

Q: Will oxalis come back after herbicide treatment?

A: Yes, oxalis often resprouts from underground bulbs. Expect to re-spray. Multiple applications are needed to fully eradicate.

Q: Is hand pulling or spraying more effective for oxalis?

A: Hand pulling is only practical for small patches. Spraying is needed for large infestations and to reach the root system.