Purple Weeds In Grass

If you’ve noticed purple weeds in grass, you’re not alone. These unexpected garden invaders pop up in lawns everywhere, and while some are harmless, others can quickly take over. Identifying them is the first step to getting your green carpet back.

This guide will help you figure out what you’re dealing with. We’ll cover common types, whether they’re a problem, and how to remove them for good.

That splash of purple might look pretty, but it’s often a sign your lawn is under siege. These weeds thrive where grass is struggling, so their presence is a clue about your lawn’s health.

Common Purple Lawn Weeds: A Quick Identification Guide

Not all purple weeds are the same. Here are the most frequent offenders you might find.

Henbit (Lamium amplexicaule)

This is a very common sight in early spring. You’ll recognize it by its:

Square stems (a hallmark of the mint family).
Small, trumpet-shaped purple flowers.
Leaves that clasp tightly around the stem.
Low-growing, mat-forming habit.

Henbit is a winter annual, meaning it sprouts in fall, lives through winter, and flowers in spring before dying in the heat.

Purple Deadnettle (Lamium purpureum)

Often confused with Henbit, Purple Deadnettle is its close cousin. Key differences include:

More triangular, heart-shaped leaves.
Leaves near the top often have a purplish tint.
The leaves have stalks and do not clasp the stem as tightly.

It shares the same life cycle as Henbit and often grows alongside it.

Ground Ivy (Creeping Charlie) (Glechoma hederacea)

This is a perennial menace that spreads aggressively. It’s a bigger problem than the annuals. Look for:

Round, scalloped leaves with a strong minty smell when crushed.
Long, creeping stems that root at the nodes.
Small, funnel-shaped blue-to-purple flowers.

It loves shady, moist areas and can form dense mats that choke out grass.

Wild Violet (Viola sororia)

These might seem charming, but they are tough perennial weeds. They have:

Heart-shaped, glossy leaves.
Distinct purple (sometimes white or yellow) flowers with five petals.
A deep, extensive root system with rhizomes.

They are very persistent and can survive in dense shade where grass won’t grow.

Why Are These Weeds In My Lawn?

Weeds are opportunists. They move into lawns that are thin, weak, or under stress. Common reasons include:

Compacted Soil: Grass roots need air. Hard soil prevents this, but weeds like Ground Ivy don’t mind.
Low Mowing: Cutting your grass too short weakens it and allows low-growing weeds like Henbit to get sunlight.
Poor Soil Nutrition: An underfed lawn is a weak lawn. Weeds often outcompete grass in poor soil.
Excess Moisture: Overwatering or poor drainage creates ideal conditions for many invasive weeds.
Bare Spots: Any open patch of soil is an invitation for weed seeds to germinate.

How to Remove Purple Weeds From Your Lawn

The best method depends on the weed type and your gardening style. Here’s a step-by-step approach.

Step 1: Correct Identification

Before you do anything, figure out which weed you have. Is it an annual (Henbit, Deadnettle) or a perennial (Ground Ivy, Violets)? This dictates your strategy. Perennials require more agressive tactics.

Step 2: Manual Removal

For small patches, pulling can be effective if done correctly.

Best Time: Pull after a rain, when the soil is soft.
Tool: Use a dandelion weeder or a sturdy garden knife for taprooted weeds like Violets.
Goal: Get the entire root system. Perennials will regrow from left-behind roots or rhizomes.
Dispose of the weeds; don’t leave them on the lawn as they can re-root.

Step 3: Cultural Controls (Changing Lawn Care)

This is about making your grass so healthy that weeds can’t compete. It’s the most important long-term solution.

Mow High: Keep your grass at 3-4 inches tall. This shades the soil, preventing weed seeds from sprouting.
Water Deeply & Infrequently: Water about 1 inch per week, all at once, to encourage deep grass roots.
Aerate: Core aerate your lawn annually to relieve soil compaction.
Fertilize Appropriately: Feed your lawn based on a soil test. Healthy grass grows thick and crowds out weeds.
Overseed: In fall, spread grass seed over thin areas to fill them in with desirable grass.

Step 4: Using Herbicides

For severe infestations, especially of perennials, herbicides may be necessary. Always read and follow the label exactly.

For Henbit & Deadnettle (Annuals): A broadleaf post-emergent herbicide in early spring when the plants are young is very effective. A pre-emergent in fall can prevent them from sprouting.
For Ground Ivy & Wild Violets (Perennials): These are tougher. Use a post-emergent herbicide containing triclopyr or a combination of 2,4-D, dicamba, and mecoprop. You may need multiple applications in fall, when perennials are sending energy to their roots.
Spot Treat: Instead of spraying the whole lawn, use a sprayer to apply herbicide only to the weed patches.

Note that some herbicides can damage certain grass types, so check compatability. Also, avoid using herbicides on new grass seed for at least until it’s been mowed several times.

Prevention: The Best Cure

Stopping weeds before they start is easier than removing them. A proactive lawn care routine is key.

Stick to a seasonal lawn care schedule (fertilizing, aerating, dethatching).
Test your soil every few years and amend it as recommended.
Reseed bare spots immediately.
Clean your mower blades after cutting a weedy area to avoid spreading seeds or plant parts.

FAQ: Purple Weeds in Lawns

Q: Are purple flowering weeds bad for my lawn?
A: Most are. They compete with grass for water, nutrients, and space. Some, like Wild Violets, are very difficult to remove once established.

Q: Can I just mow over purple weeds?
A: Mowing can prevent annuals like Henbit from seeding, but it won’t kill them or perennial weeds. In fact, mowing can spread creeping weeds like Ground Ivy by chopping and dispersing their stems.

Q: Is there a natural way to kill purple weeds?
A> For small areas, manual removal is best. Broadleaf herbicides made from iron (iron HEDTA) are a natural option that works by causing oxidative stress in the weed. Vinegar-based sprays are non-selective and will kill grass too, so they are only for spot treatment in patio cracks, not lawns.

Q: Why do I have so much Creeping Charlie?
A: Ground Ivy thrives in moist, shady, and compacted areas. Improving drainage, reducing shade if possible, and core aerating are crucial steps alongside any treatment.

Q: Should I leave Wild Violets alone?
A: That’s a personal choice. If they’re in a far corner of the yard and you like them, they can stay. But know they are aggressive and will spread into lawn areas, where they are very hard to erradicate later.

Dealing with purple weeds in your grass is a common part of lawn care. By correctly identifying the invader, using the right removal tactic, and most importantly, building a thick, healthy lawn, you can keep your green space looking its best. Remember, a weed is just a plant growing where you don’t want it, but with a little knowledge and effort, you can tip the balance back in favor of your grass.