Those purple flowers in your lawn might be weeds, and identifying them is key to control. Recognizing common weeds with purple flowers is the first step to managing them effectively. This guide will help you name them, understand their impact, and choose the right removal strategy.
Weeds With Purple Flowers
Many plants with purple blooms can be considered weeds when they grow where you don’t want them. They can be annuals, biennials, or perennials, each with different life cycles that affect how you deal with them. Some are merely unsightly, while others are invasive and can harm local ecosystems or outcompete your grass and garden plants.
Common Purple Flowering Weeds In Lawns And Gardens
Here are some of the most frequent offenders you’re likely to encounter. Correct identification is crucial because it informs the best method and timing for control.
Creeping Charlie (Glechoma Hederacea)
Also known as ground ivy, this perennial weed is a member of the mint family. It spreads aggressively via creeping stems that root at the nodes. It thrives in shady, moist areas and can quickly form a dense mat that chokes out grass.
- Leaves: Round or kidney-shaped with scalloped edges, growing opposite each other on square stems.
- Flowers: Small, lavender to purple, funnel-shaped blooms that appear in clusters in spring.
- Control: Difficult to eradicate. Hand-pulling is effective for small patches if you remove all stems. For larger infestations, a broadleaf herbicide containing dicamba in fall is often most effective.
Purple Deadnettle (Lamium Purpureum) and Henbit (Lamium Amplexicaule)
These two winter annuals are often confused. They germinate in fall or early spring, flower, set seed, and then die. They commonly invade thin or bare spots in lawns and garden beds.
- Purple Deadnettle: Leaves are triangular or heart-shaped, distinctly reddish-purple at the top, with a purplish tint on the upper leaves. The upper leaves have short petioles.
- Henbit: Leaves are rounded with deep lobes, and the upper leaves clasp directly around the square stem. Flowers are a brighter pink-purple.
- Control: Both are easier to control. Hand-weeding before they set seed works well. A pre-emergent herbicide applied in early fall can prevent them. Post-emergent herbicides in early spring are also effective.
Wild Violet (Viola Sororia)
This perennial is one of the toughest lawn weeds to control. It spreads by seeds and underground rhizomes. Its waxy leaves and deep roots make it resistant to many common herbicides.
- Leaves: Heart-shaped with a glossy, waxy coating and toothed margins. They grow in a basal rosette.
- Flowers: Typically deep violet, but can range to blue or white, with five petals. They appear in mid to late spring.
- Control: Hand-digging, ensuring you get the entire root system. For chemical control, use a herbicide with triclopyr or quinclorac, often requiring multiple applications. Fall is the best time to treat.
Thistles (Cirsium and Carduus Spp.)
Several thistle species produce purple flowers. They are biennial or perennial and are known for their spiny foliage. Musk and Canada thistle are particularly invasive.
- Leaves: Deeply lobed with sharp, stiff spines along the edges.
- Flowers: Globe-shaped, pinkish-purple to magenta flower heads that are often fuzzy.
- Control: Wear thick gloves. Dig out the entire taproot for young plants. For perennial types like Canada thistle, systemic herbicides containing glyphosate or clopyralid are usually necessary, applied when the plant is in bud to flower stage.
Why Identification Matters Before Removal
You cannot effectively manage a weed if you don’t know what it is. Different weeds have different weaknesses. Applying the wrong herbicide is a waste of time and money, and can damage desirable plants. For instance, a herbicide for broadleaf weeds won’t work on grassy weeds, and some chemicals can kill your flowers or shrubs if applied incorrectly.
Knowing the life cycle tells you when to act. Pulling an annual weed before it sets seed can eliminate it for the season. Attacking a perennial weed when it’s sending energy to its roots in the fall makes herbicide treatments more effective. Always take a close look at the leaf shape, stem, flower structure, and growth habit before taking action.
How To Remove Purple Flowering Weeds
Once you’ve identified your weed, you can choose the best removal method. Consider the size of the infestation, the weed type, and your preference for organic or chemical solutions.
Manual Removal Techniques
Physical removal is immediate and chemical-free. It’s best for small areas or isolated weeds.
- Hand-Pulling: Effective for annuals and young perennials. Ensure the soil is moist to help get the entire root. For taprooted weeds like thistles, use a dandelion digger or similar tool to loosen the soil and lift the root.
- Digging: Use a garden trowel or fork for perennial weeds with extensive root systems, like wild violet. You must remove all rhizomes or tubers to prevent regrowth.
- Smothering: For patches in garden beds, cover the area with cardboard or several layers of newspaper, then top with mulch. This blocks sunlight and kills the weeds over a season.
Chemical Control Options
For large-scale infestations, herbicides may be the most practical solution. Always read and follow the label instructions precisely.
- Selective Herbicides: These target specific plant types, like broadleaf weeds, without harming grasses. Look for products containing 2,4-D, dicamba, MCPP, or triclopyr for broadleaf weeds in lawns.
- Non-Selective Herbicides: Products like glyphosate kill any plant they contact. Use these for spot-treating weeds in patios, driveways, or before establishing a new garden bed. Be extremly careful to avoid drift onto wanted plants.
- Pre-Emergent Herbicides: These create a barrier in the soil that prevents weed seeds from germinating. Apply them in early fall for winter annuals like henbit, or early spring for summer annuals.
Preventing Future Infestations
The best defense is a thick, healthy lawn and garden. Weeds are opportunists that colonize weak, thin, or bare soil.
- Mow High: Keep your lawn at 3-4 inches tall. Longer grass shades the soil, preventing weed seeds from sprouting.
- Fertilize Appropriately: Feed your lawn and garden plants to keep them vigorous and competitive.
- Water Deeply and Infrequently: This encourages deep root growth in your grass, making it more drought-tolerant and resilient.
- Reseed Bare Spots: Quickly fill in any thin areas in your lawn with appropriate grass seed to deny weeds a foothold.
- Use Mulch: Apply a 2-3 inch layer of mulch in garden beds to suppress weeds and retain moisture.
Ecological Impact and Benefits
While we label them as weeds, some purple-flowering plants have ecological value. It’s worth considering if total eradication is always necessary.
When To Consider Tolerance
In less formal areas of your yard, some “weeds” can provide benefits. Many are excellent nectar sources for early-emerging bees, butterflies, and other pollinators when few other flowers are in bloom. For example, creeping charlie and deadnettle are important early spring food sources for bees. If the infestation is small and not threatening other plants, you might decide to let them be in an out-of-the-way corner to support local wildlife.
Invasive Species Of Concern
However, some purple-flowered weeds are highly invasive and can cause significant harm. They outcompete native plants, reducing biodiversity and disrupting local ecosystems. Purple loosestrife (Lythrum salicaria) is a notorious example in wetland areas, though it’s less common in home lawns. If you suspect you have an invasive species, it is often recommended to remove it to prevent its spread to natural areas. Check with your local extension service for a list of invasive plants in your region.
Frequently Asked Questions
What Are The Most Common Weeds With Purple Flowers?
The most common include Creeping Charlie (Ground Ivy), Purple Deadnettle, Henbit, Wild Violets, and various Thistles. Each has distinct features for identification.
How Do I Get Rid Of Purple Weeds In My Lawn Without Chemicals?
Manual removal by hand-pulling or digging is the primary method. Ensure you get the entire root. Improving lawn health through proper mowing, watering, and fertilization is the best long-term, organic prevention strategy to crowd out weeds.
Are Purple Flowering Weeds Poisonous?
Most common lawn weeds are not highly toxic, but some can be if ingested in large quantities by pets or livestock. It’s always best to prevent pets from eating any unknown plants. For specific concerns, consult a veterinarian or a plant identification guide.
When Is The Best Time To Spray Weeds With Purple Flowers?
Timing depends on the weed. For many perennials like Creeping Charlie and Wild Violet, fall is ideal as the plant is sending energy to its roots, carrying the herbicide down. For annuals like Henbit, early spring before they set seed is effective. Always follow the specific herbicide label instructions.
Can I Eat Any Purple Flower Weeds?
Some are edible. Wild violets leaves and flowers can be used in salads or as garnish. However, you must be 100% certain of your identification, ensure the plants have not been treated with pesticides, and only consume them in moderation. Many plants look similar and can be toxic, so thorough research is essential.