Oxalis, often known as “clover” or “sourgrass,” is a pesky weed that can take over your garden, lawn, or indoor plants if not managed properly. While its small, clover-like leaves and delicate flowers may seem innocent, oxalis can quickly become invasive and difficult to eradicate. Here’s how to get rid of oxalis and prevent it from coming back.
What is Oxalis?
Oxalis is a fast-growing weed with distinct trifoliate leaves and small yellow, pink, or white flowers. It can spread through both seeds and underground rhizomes (creeping roots), making it tough to control. There are many varieties of oxalis, some of which are annuals and others are perennials, but the method to control them remains largely the same.
1. Manual Removal
One of the most effective ways to control oxalis, especially if you notice small patches, is by manually removing it.
Steps for Manual Removal:
- Dig up the roots: Use a garden fork or hand trowel to dig around the oxalis plant. Be sure to remove the entire root system, including any rhizomes (underground stems) that may be spreading the plant.
- Dispose properly: Once you’ve removed the plant, do not compost it, as it may regenerate from pieces of root. Instead, place it in the trash.
- Repeat regularly: Oxalis has the ability to sprout quickly from any leftover roots or rhizomes, so be persistent. Remove new growth as soon as you notice it.
2. Use Mulch
Mulching is a great way to smother oxalis and prevent its growth, particularly in garden beds and lawns. Mulch blocks sunlight from reaching the soil, which is necessary for germination.
Steps for Mulching:
- Choose the right mulch: Use organic mulch such as wood chips, bark, or straw. Apply a thick layer (about 3-4 inches) around the plants.
- Keep the mulch intact: Be careful not to disturb the mulch layer, as oxalis can find gaps and sprout through.
- Apply mulch in the fall: For better results, mulch in late fall after you’ve removed as much oxalis as possible.
3. Herbicides (Chemical Control)
If oxalis is widespread and manual methods aren’t enough, herbicides may be necessary. Be sure to select a herbicide that targets broadleaf weeds without harming your lawn or garden.
Steps for Using Herbicides:
- Choose the right herbicide: Look for a selective post-emergent herbicide designed to kill broadleaf weeds like oxalis, such as products containing 2,4-D or dicamba.
- Spot treat: If possible, spot treat the oxalis rather than spraying the entire area. This will reduce the impact on surrounding plants.
- Follow manufacturer instructions: Always read and follow the manufacturer’s instructions on the herbicide label. This ensures effectiveness and safety.
- Consider natural alternatives: If you prefer organic options, look for herbicides that contain ingredients like vinegar or clove oil. These can be effective but may require more frequent application.
4. Improve Lawn Care Practices
Oxalis is often more invasive in poorly maintained lawns. Strengthening your lawn can help it naturally resist oxalis and other weeds.
Tips for Lawn Care:
- Mow regularly: Keeping your lawn mowed at the right height (usually about 2-3 inches for most grasses) prevents oxalis from flowering and setting seeds.
- Fertilize appropriately: Use balanced fertilizer to encourage healthy grass growth. Healthy lawns are better able to outcompete weeds like oxalis.
- Water wisely: Water your lawn deeply and infrequently to encourage deep root growth. Shallow watering can stress grass and allow weeds to thrive.
- Aerate your lawn: Aerating the soil helps grass roots grow deeper, which can make it more difficult for oxalis to establish itself.
5. Preventing Future Growth
Once you’ve successfully removed oxalis, it’s crucial to take steps to prevent it from coming back. Oxalis can spread quickly, so maintaining your lawn or garden with these practices will help keep it under control.
Preventive Measures:
- Seed control: If oxalis is already flowering, be sure to remove the flowers before they go to seed. Deadhead any blooms you find to prevent seeds from spreading.
- Keep the soil healthy: Avoid compacting the soil, which can make it easier for oxalis to spread. Regularly amend your soil with organic matter to improve its structure and health.
- Monitor regularly: Continue to monitor the area for any signs of new oxalis growth, especially after rainfall or when soil temperatures rise in the spring.
6. Using Boiling Water
Boiling water can be an effective method for killing oxalis, especially in cracks and between paving stones. This method is non-selective, so be cautious not to spill on surrounding plants.
Steps for Using Boiling Water:
- Boil a kettle of water: Once the water is boiling, carefully pour it directly onto the oxalis plants.
- Repeat as necessary: Boiling water may not kill the roots immediately, so you may need to repeat the process a few times for complete eradication.
7. For Indoor Oxalis (If You Have It in a Pot)
If oxalis has invaded your indoor plants, you can manage it similarly to outdoor control, but with a more delicate approach.
Steps for Indoor Control:
- Repot the plant: If oxalis is growing in a container, carefully remove the entire plant and any soil that has oxalis roots.
- Inspect new soil: Use fresh, weed-free potting soil to repot the plant.
- Maintain healthy indoor conditions: Ensure that your indoor plants have proper lighting, drainage, and space to grow, which will help discourage weed growth like oxalis.
A Persistent Approach to Oxalis Control
While getting rid of oxalis can be a challenge due to its aggressive growth and ability to regenerate from roots, persistence is key. By using a combination of manual removal, mulch, proper lawn care, and appropriate herbicide use, you can take control of oxalis in your garden or lawn. The key is to be vigilant, monitor for regrowth, and employ a consistent strategy to keep this invasive weed at bay.