Weeds With Purple Flowers

Purple-flowered weeds in your lawn can indicate compacted soil or low nitrogen levels. While these plants often get a bad reputation, knowing what they are and why they show up is the first step to a healthier yard. You don’t need to be a botanist to figure out what is growing in your grass, but a little identification goes a long way.

In this guide, we will walk through the most common types of purple weeds, how to remove them, and how to stop them from coming back. You will learn to spot the difference between a harmless wild violet and an aggressive invader like creeping charlie.

Why Do Purple Weeds Appear?

Weeds are not random. They grow where conditions suit them. If you see a lot of purple flowers, your soil is telling you something. Most of these plants prefer moist, shady areas with poor drainage. Others thrive in soil that lacks specific nutrients.

Before you start pulling, test your soil. A simple kit from a garden center will tell you the pH level and nutrient content. This information helps you fix the root cause, not just the symptom.

This section covers the most frequent offenders you will find in North American lawns and gardens. We will look at their growth habits, leaf shapes, and the best ways to control them.

Creeping Charlie (Ground Ivy)

Creeping Charlie is one of the most common weeds with purple flowers. It is a perennial that spreads rapidly through stems that root at the nodes. The leaves are round or kidney-shaped with scalloped edges. The flowers are small, funnel-shaped, and range from light purple to deep violet.

This weed loves shade and moist soil. It often takes over areas where grass struggles to grow. If you have a dense patch of it, your lawn is likely too shady or the soil is too wet.

How to remove it:

Hand pulling works for small patches, but you must remove all the stems.
Use a broadleaf herbicide containing triclopyr in the fall.
Improve drainage by aerating the soil.
Trim tree branches to let in more sunlight.

Wild Violet

Wild violets are often mistaken for creeping charlie, but they have distinct heart-shaped leaves with pointed tips. The flowers are usually a rich purple, though some varieties are white or blue. They have a thick root system that makes them hard to pull by hand.

These plants are tough. They can survive mowing and even thrive in poor soil. They spread through seeds and underground rhizomes. Once established, they are very difficult to eradicate.

Control methods:

Apply a post-emergent herbicide in late spring or early fall.
Use a product with dicamba or 2,4-D for best results.
Do not till the soil, as this spreads the rhizomes.
Maintain a thick, healthy lawn to outcompete them.

Purple Dead Nettle

Purple dead nettle is a winter annual that appears in early spring. It has square stems, which tells you it is in the mint family. The upper leaves have a purple or reddish tint, and the small tubular flowers are pinkish-purple.

This weed grows low to the ground and forms dense mats. It prefers disturbed soil and garden beds. It does not compete well with thick grass, so a healthy lawn is your best defense.

Removal tips:

Hand pull before it sets seeds in late spring.
Mulch garden beds to prevent germination.
Use a pre-emergent herbicide in early fall.

Henbit

Henbit looks very similar to purple dead nettle. The main difference is that henbit has more elongated leaves that are not as deeply lobed. The flowers are purple and appear in whorls around the stem. It also has square stems and grows in cool weather.

Henbit is not aggressive. It usually disappears when temperatures rise. However, it can be unsightly in large numbers. It thrives in thin lawns and newly seeded areas.

How to manage henbit:

Mow regularly to prevent flowering.
Apply a fall pre-emergent to stop seeds from sprouting.
Improve lawn density with overseeding in the fall.

Common Self-Heal

Common self-heal is a low-growing perennial that forms dense patches. It has oval leaves and clusters of purple to lavender flowers that look like tiny hoods. It is often found in lawns that are mowed too short.

This weed tolerates foot traffic and poor soil. It spreads by creeping stems that root at the nodes. It is not easy to remove once it takes hold.

Control strategies:

Raise your mower blade to 3 inches or higher.
Water deeply but infrequently to encourage deep grass roots.
Spot treat with a selective herbicide.

Forget-Me-Nots

Forget-me-nots are technically a flowering plant, but they can become weedy in the right conditions. They produce clusters of small, bright blue-purple flowers with yellow centers. They are biennial or short-lived perennials that self-seed aggressively.

They prefer moist, shady spots. In a garden, they can take over a border quickly. In a lawn, they usually appear in damp, low areas.

Managing forget-me-nots:

Pull them before they set seed.
Improve drainage in low spots.
Use a thick layer of mulch in garden beds.

Bull Thistle

Bull thistle is a tall, prickly plant with large, purple flower heads. It is a biennial that forms a rosette of spiny leaves in its first year. In the second year, it sends up a tall flower stalk that can reach 6 feet.

This weed is a serious problem in pastures and meadows. It can also appear in neglected lawns. The spines make it painful to handle, so wear gloves.

Removal methods:

Cut the flower heads before they release seeds.
Dig out the taproot with a shovel.
Use a systemic herbicide like glyphosate for large infestations.

Spotted Knapweed

Spotted knapweed is an aggressive invasive species in many regions. It has pink to purple flowers that resemble small thistles. The bracts under the flower have a black-tipped fringe, which gives it the “spotted” name.

It grows in dry, sunny areas and can crowd out native plants. It is a particular problem in rangelands and along roadsides. In a home lawn, it is less common but can appear if you have sandy, well-drained soil.

Control options:

Hand pull young plants before they flower.
Mow repeatedly to deplete root reserves.
Introduce biological controls like root-boring weevils in severe cases.

How To Identify Unknown Purple Weeds

If you find a purple weed that is not on this list, you can identify it using a few simple steps. Look at the leaf shape, the stem, and the flower structure. Take a photo and compare it to online databases.

Here is a quick checklist:

Is the stem square or round?
Are the leaves opposite or alternating on the stem?
Does the plant have a taproot or fibrous roots?
Is the flower a single bloom or a cluster?
Does the plant have a distinct smell when crushed?

Answering these questions will narrow down the possibilities. You can also use a plant identification app. Most are free and surprisingly accurate.

Natural Ways To Remove Purple Weeds

If you prefer not to use chemicals, there are several organic methods that work well. These require more effort but are safer for pets and beneficial insects.

Vinegar solution: Mix white vinegar with a few drops of dish soap. Spray the leaves on a sunny day. The acetic acid burns the foliage. This works best on young weeds.

Boiling water: Pour boiling water directly on the weed. This kills the top growth instantly. It may take multiple applications for deep-rooted plants.

Corn gluten meal: This is a natural pre-emergent. Apply it in early spring to prevent seeds from germinating. It also adds nitrogen to the soil.

Solarization: Cover the area with clear plastic for 4-6 weeks during the hottest part of summer. The heat kills weed seeds and roots in the top few inches of soil.

Chemical Control Options

Sometimes, natural methods are not enough. For stubborn perennial weeds, a selective herbicide is the most effective choice. You need to pick the right product for your specific weed.

Broadleaf herbicides: Products containing 2,4-D, dicamba, or MCPP are effective against most broadleaf weeds. They do not harm grass. Apply them when the temperature is between 60 and 85 degrees Fahrenheit.

Non-selective herbicides: Glyphosate kills everything it touches. Use it only for spot treatments. It is best for weeds growing in cracks in driveways or patios.

Pre-emergents: These stop seeds from sprouting. They are useful for annual weeds like henbit and dead nettle. Apply them in early fall or early spring.

Always read the label before applying any chemical. Follow the mixing instructions exactly. Wear protective clothing and keep children and pets off the lawn until the product dries.

Preventing Purple Weeds From Returning

Prevention is easier than cure. A healthy, thick lawn is the best defense against weeds. Weeds cannot establish themselves if there is no bare soil for seeds to land on.

Mowing practices:

Set your mower blade to 3 to 4 inches.
Never cut more than one-third of the grass blade at a time.
Keep your mower blades sharp to prevent tearing.

Watering habits:

Water deeply and less frequently.
Water in the early morning to reduce evaporation.
Avoid watering in the evening, which promotes fungal growth.

Fertilization:

Test your soil to know what nutrients are missing.
Apply nitrogen in the fall for cool-season grasses.
Use a slow-release fertilizer to avoid burning.

Aeration: Compacted soil is a major cause of weed problems. Aerate your lawn once a year to relieve compaction. This allows water, air, and nutrients to reach the roots.

Overseeding: In the fall, overseed thin areas. This fills in bare spots and prevents weeds from taking hold. Choose a grass seed that matches your existing lawn.

When To Call A Professional

If you have a severe infestation that you cannot control, it may be time to call a lawn care service. Professionals have access to stronger products and equipment. They can also identify weeds that are difficult to distinguish.

Consider hiring a pro if:

Weeds cover more than 50% of your lawn.
You have tried multiple methods without success.
You are dealing with an invasive species like spotted knapweed.
You have health concerns that make chemical use risky.

A professional will usually apply a combination of pre-emergent and post-emergent treatments. They may also offer aeration and overseeding services to improve the overall health of your lawn.

Frequently Asked Questions

Are purple flower weeds harmful to my lawn?

Most are not directly harmful, but they compete with grass for water and nutrients. Some, like bull thistle, can be painful if you step on them. Others, like creeping charlie, can smother grass entirely.

Can I eat any weeds with purple flowers?

Yes, some are edible. Purple dead nettle and henbit are both edible and can be used in salads or teas. However, you must be 100% sure of the identification before consuming any wild plant. Do not eat anything that may have been treated with chemicals.

Why do I only see purple weeds in the spring?

Many of these are cool-season annuals. They germinate in the fall, grow slowly through winter, and bloom in early spring. They die off when temperatures rise above 80 degrees Fahrenheit.

Will mowing get rid of purple weeds?

Mowing helps prevent seed production, but it does not kill the plant. Perennial weeds like wild violet will regrow from their roots. You need to combine mowing with other control methods.

What is the fastest way to kill purple weeds?

A non-selective herbicide like glyphosate works the fastest, but it kills the grass too. For selective control, use a broadleaf herbicide. It takes about 2-3 weeks to see full results.

Final Thoughts On Managing Purple Weeds

Dealing with weeds with purple flowers does not have to be a constant battle. Start by identifying what you have. Then, address the underlying soil and sunlight issues. Finally, apply the right control method at the right time.

Remember that a perfect lawn is not realistic. A few weeds are normal and even beneficial for pollinators. The goal is to keep them from taking over, not to eliminate every single one.

If you stay consistent with your lawn care routine, you will see a significant reduction in weeds over time. Be patient. It takes a season or two to see lasting results.

Take action today. Walk your yard, identify the purple weeds, and pick one control method to try. Your lawn will thank you next year.