Hello Angie, I'm sorry to hear that your wildflowers are being invaded by Sweet Yellow Clover. It can be a persistent weed, especially if it's been allowed to seed and establish itself in your lawn. Here are some steps you can take to manage the Sweet Yellow Clover:

1. Manual Removal: Start by removing the clover manually. This is most effective when the plants are young and haven't yet flowered and set seed. You can use a hand trowel or a lawn mower set to a high setting to cut the clover.

2. Herbicide Application: If manual removal isn't feasible or the clover has already flowered and set seed, you may need to apply an herbicide. Look for a selective herbicide that targets broadleaf weeds like clover without harming your grass. It's important to apply the herbicide correctly to avoid damaging your lawn.

3. Cultural Practices: Ensure that your lawn is healthy and vigorous. A dense, healthy lawn can outcompete weeds, reducing the likelihood of clover taking hold. Regular mowing, watering, and fertilizing can help maintain a healthy lawn.  You can have a soil test done to ensure the soil is optimal for growing grass.  Here is the link: https://soiltest.cfans.umn.edu/

4. Regular Monitoring: Keep an eye on your lawn for any signs of clover re-emerging. Early detection and removal can help prevent the clover from becoming a problem again.

Remember, it's important to follow all label instructions when using herbicides and to consider the potential impact on other plants and wildlife in your area. If you have any further questions or need more specific advice, feel free to ask.