There are plenty of different weeds that can infest your grass, and if you want to keep a velvety smooth lawn, it can seem overwhelming to deal with them. Today we’re going to look at the various purple-flowered weeds that you might find taking over, and find some solutions to deal with them.
1. Purple Dead Nettle
Purple dead nettle (Lamium purpureum) is a native of Europe that has become a widespread invasive weed across North America. While some appreciate it as medicinal plant, it can quickly take over a lawn or garden bed. Because it spreads by stem or root fragments, it’s hard to eradicate once it gets established. Pulling out individual plants is effective before they spread and should eliminate the need for chemical herbicides.
2. Creeping Thistle
Even though this is also known as Canada thistle, creeping thistle (Cirsium arvense) is actually native to Europe. It spreads rapidly in wild settings, but may also creep in from the edges of your lawn. If your lawn has bare patches, seeds may land there and germinate. Repeated mowing before the flowers set seed has proven to be successful.
3. Wild Violets
Wild violets (viola papilionacea) put on gorgeous show in mid-spring, but once they’ve finished blooming they can become a nuisance in your garden or lawn. They spread both by roots and seeds, so even if you like their flowers, pull them out before they become a problem after the flowers have faded. Try to get as much of the root as possible to prevent them from growing back.
4. Common Mallow
The common mallow (Malva neglecta) is another European import that now grows across North America. The best way to get rid of small plants in your lawn is by cutting them off at the crown with a sharp hoe. You may need to go back a second time if a more mature plant regrows from its well-developed roots.
5. Creeping Charlie
Creeping Charlie (Glechoma hederacea) came to North America with European settlers and is now the bane of many a gardener’s existence. It’s a stubborn ground cover that loves moist, shady spots and once it’s established it can be almost impossible to eradicate. For minor infestations, try pulling by hand, but if it’s formed a large patch, a chemical herbicide is certainly an easier solution. Make sure the one you get will kill creeping Charlie- not all of them work on this tough weed!
6. Dame’s Rocket
Dame’s Rocket (Hesperis matronalis) was brought to North America as a garden plant by settlers, but it easily escaped from cultivation and is now a widespread weed, albeit a lovely one. You can see it growing in profusion in late spring as it blooms in swathes of purple and white along roadsides and creeks. Burning and hand pulling are the recommended methods for dealing with this invasive plant.
7. Purple Loosestrife
Purple loosestrife (Lythrum salicaria) became a notorious weed in wetlands in the 1990s, but it’s not likely to become a problem in your lawn, as it thrives in wet soils. If you do have a patch of it in your yard, however, you should get rid of it. Dig it up and dispose of it in a sealed garbage bag.
8. Wild Indigo
Wild indigo (Baptisia australis) is usually cultivated as perennial ornamental, as its purple flowers are a lovely addition to the late spring garden. It has a moderate spread and is unlikely to become a problem. However, because it had a single tap root, if it is disturbed it will probably die. This makes getting rid of unwanted false indigo fairly easy.
9. Forget-Me-Not
Forget-me-not (Myosotis sylvatica) is another plant that is appreciated in the right place, but can become a nuisance if it spreads into a lawn. Native to Africa, they’ve become a widespread wildflower in North America, as they don’t have natural predators to keep them in check. Start by pulling or hoeing the plants before they go to seed. They also spread from their roots, so you may need to deal with a patch a few times before they die completely.
10. Purple Crownvetch
Purple crownvetch (Securigera varia) is a European import that has been sold for decades as an erosion control ground cover, especially on slopes, but it’s become a serious invasive in many parts of North America. If it’s invading your yard, start by pulling plants, mowing the patch down repeatedly, or burning. If all else fails, try a broadleaf herbicide.
11. Wild Geranium
Wild geranium (Geranium maculatum), also known as cranesbill, is best controlled by frequent low mowing, which will prevent it from setting seed. You can also spread corn gluten over your lawn in October to prevent seeds from sprouting the following spring.
12. Black Nightshade
Black nightshade (Solanum nigrum) is a Eurasian native that has adapted well to North America, and it is now widespread across much of the continent. It spreads by seed; the best way to eliminate it is by digging out young plants before they set seed.
13. Henbit
Henbit (Lamium amplexicaule) is an annual weed that arrived here from Eurasia and is now found all across North America. Individual plants can be pulled or burnt, or cut off with a sharp hoe.
14. Heal-All
Heal-all (Prunella vulgaris) is a tough perennial native to much of the northern hemisphere, and is extremely invasive in lawns. If you catch it early, dig up the plants, getting as much of the root system as possible before it gets established and starts to spread. You can also use a flame weeder on this shallow-rooted plant. A good preventative measure is to dethatch and aerate your lawn to improve its overall health and discourage weeds.
15. Bull Thistle
Bull thistle (Cirsium vulgare) is native to Europe and western Asia, and now grows all across North America. It’s also known as the common or spear thistle. Because it spreads by its light, wind-carried seeds, the best control is to cut down any plants before they set seed.
16. Spotted Knapweed
Spotted knapweed (Centaurea maculosa) is a biennial thistle native to Europe that spreads easily by seed; one plant can produce as many as 140,000 seeds! It’s absolutely essential to cut the plants down or pull them up before they flower and set seed.
17. Dove’s-Foot Crane’s-Bill
Native to Europe and North Africa, dove’s-foot cranesbill (Geranium molle) is now found in much of North America. The best way to eliminate it from your lawn is by hand weeding.
18. Chicory
Chicory (Cichorium intybus) is a common weed throughout North America, although it is native to Europe. Because it’s a perennial, it can be very difficult to eliminate once it gets established. It spreads by seed, so if you do dig them out, make sure you get them before they’ve set seed. You can also keep cutting the plant off at the crown, and eventually the roots will use up their stored food and the plant will die.
19. Purpletop Verbena
Purpletop verbena (Verbena bonariensis) is only a problem in regions of North America with mild winters, as this South American native is a tender perennial. However, in those areas it can become quite a problem. If you just have a few plants popping up, nip them in the bud by pulling or digging them out.
How To Get Rid of Purple Weeds in Lawn (Explained)
Let’s start with looking at the methods of eradicating weeds.
The first step in preventing weeds in your lawn is by growing a thick, healthy lawn with no bare spots for weeds to take hold.
If weeds do appear, however, it’s always best to try organic methods first, and only resort to herbicides when all else fails. Chemical herbicides may get rid of the weeds, but they can be injurious to plants you don’t want to kill, as well as animals and humans. Some of them may be carcinogenic, so other methods should be your first go-to.
The first rule is that you should always get rid of weeds before they set seed. That way, you don’t just kill the existing plant, but also stop them from reproducing. Once a weed has bloomed, you’re racing against time, so weed early and weed often.
If you can pull weeds out by hand, do so. If you have very loose, sandy soil, you can probably pull them without any other preparation, but if your soil is hard clay, wait until after a good rain has softened the ground, or you’ve let a sprinkler run for a few hours. That way you’re more likely to get the whole root along with the top growth. For many weeds, leaving a root fragment in the ground can cause it to sprout a whole new plant, so be thorough.
If you can’t pull them out, use a garden fork or trowel to get as much of the root out of the ground as possible.
Some weeds just need to be cut off at the crown with a sharp hoe. For a large patch of weeds, try mowing them down at the lowest possible height to get as much of the top growth as possible. You may have to do this several times, but eventually the root system will be starved of food and die off.
If you have random weeds popping up throughout your lawn, a fun way to kill them is with a flame weeder. This contraption uses a propane flame to zap them dead. It’s effective and satisfying!
Weeds can also be sprayed with a strong vinegar solution to kill them. Just be careful not to end up spraying your grass as well.
A great way to prevent annual weeds from sprouting is spreading a layer of corn gluten over your lawn in October.
Finally, if all else fails, go for the chemical herbicides. 2-4-D is the most popular weed killer, especially for lawns, because it only kills broadleaf plants and doesn’t affect grasses. It is, however, a potential carcinogen and may cause other health problems. If you use it, wear protective gear while applying it, and keep children and animals off the lawn for a day or so.
Final Thoughts
A weed is just a flower in a place you don’t want it, someone once said, but some plants can quickly take over a lawn or garden unless you work to eliminate them. These purple-flowered weeds can usually be dealt with without resorting to chemical herbicides, as long as you catch them before they set seed.
Janice is a retired High School teacher who is spending her leisure years keeping busy with all sorts of projects. Aside from freelance writing, she’s an enthusiastic amateur chef, home wine maker, and tends a large raised-bed vegetable garden, while at the same time running a Bed & Breakfast.