Have you got weeds with purple flowers invading your yard? Or perhaps you’re trying to figure out if a purple-flowered plant in your vegetable plot is a friend or foe? The key to understanding how to control unwanted plants is figuring out what they are in the first place. So to help, we’ve assembled a list of the most common purple flower weeds you might find in your yard or garden.
Then let’s get our hands dirty!
- What Are These Purple Weeds In My Yard?
- 1. Ground Ivy / Creeping Charlie (Glechoma hederacea)
- 2. Creeping Thistle / Canada Thistle (Cirsium arvense)
- 3. Musk Thistle (Carduus nutans)
- 4. Common Thistle / Spear Thistle / Bull Thistle (Cirsium vulgare)
- 5. Purple Dead Nettle (Lamium purpureum)
- 6. Black Nightshade (Solanum nigrum)
- 7. Wild Violet (Viola Odorata)
- 8. Forget-Me-Nots (Myosotis sylvatica)
- 9. Dove’s-Foot Cranes-Bill (Geranium molle)
- 10. Purple Loosestrife (Lythrum salicaria)
- 11. Common Self-Heal / Heal-All (Prunella vulgaris)
What Are These Purple Weeds In My Yard?
Ground ivy, creeping thistle, and wild violets are three of the most common weeds with purple flowers. But not so fast! As the saying goes, there is no such thing as a weed, just a plant in the wrong place!
In other words – I learned many years ago not to get too fussy about a few weeds, as many come and go without causing any problems. Some even bring massive benefits to your land, such as restoring soil health and protecting the exposed ground from heat and erosion.
However, we do need to keep things somewhat under control. Otherwise, we’d all be living in a jungle! Some weeds will choke our flowering plants and vegetables and creep into areas such as your carefully landscaped patio or decking. If you’ve got a formal flower garden, weeds can spoil the aesthetic effect you are trying to achieve.
In any case – knowing what your purple flowering weed is can help you when it comes to eradicating it. If you can identify that the plant is an annual, then it is simply a matter of ensuring it gets cut down before it goes to seed. Perennial plants and those that spread by rhizomes can be more problematic, and each comes with a specialized solution.
It is important to note that every weed on our list has a beneficial role in our ecosystem, helping restore the balance of nature in your garden. So, while we’re not suggesting you allow your garden to turn into a rewilding zone, it can reap huge rewards if you allow some less invasive weeds with purple flowers to reside in a wilder corner of your yard.
Some common weeds with purple flowers are also edible, with many having medicinal properties. However, never eat any plant or flower without positively identifying it first. Some of these plants have similar-looking counterparts that can be poisonous or toxic to humans!
So, let’s get to it. Here are the 11 most popular weeds with purple flowers likely in your lawn and garden.
1. Ground Ivy / Creeping Charlie (Glechoma hederacea)
Despite the name, ground ivy is not a member of the ivy family at all. It gets its name because it spreads in the same way as ivy. But it’s a distant relative of mint. And we all know how hard mint can be to get rid of once it becomes established!
Ground ivy, also known as creeping Charlie, grows in a low mat across the ground, with abundant bright green leaves on longish stalks and purple-violet flowers in clusters of two to four. The scalloped leaves are kidney-shaped. The funnel-shaped blossoms have a distinctive smell that reminds many gardeners of cat urine!
Because it grows in a thick blanket and spreads via rhizomes, ground ivy can smother grasses if it takes over your lawn. It flowers in late spring. The best time to eradicate it is when it goes dormant, later in summer. The best way to control ground ivy is by hand pulling and digging to remove the rhizomes and root system.
The Dreaded Thistle!
Many types of thistle can become problematic in your garden. But also several other varieties that can make fabulous ornamental plants! Here are some invasive thistles to be aware of when gardening.
2. Creeping Thistle / Canada Thistle (Cirsium arvense)
Of all the different thistles with purple flowers, the creeping thistle is the one that gardeners dread! They have every feature that makes them difficult to eradicate. They are perennials with an extensive root system, enabling them to grow back after being cut down.
Creeping thistles grow tall stems with spiny barbs, topped with clusters of pom-pom-like purple flowers. Improving soil fertility and repeated mowing and pulling can help eradicate this invasive plant.
3. Musk Thistle (Carduus nutans)
Have you got a tall purple flower weed making a nuisance of itself in your garden? Musk thistle could very well be the culprit!
This thistle thrives on poor-quality soil and loves to take root in the edges of paths and driveways. It has large single flowerheads with multiple vibrant purple petals on a robust, thorny stem. It is easy to tell apart from other thistles due to the white marbling on the leaves.
Also known as nodding thistle, musk thistle is not a native thistle to the United States. And it can be problematic as it crowds out native species and reduces food availability for livestock in pasture land. In several states, it has a reputation as an invasive weed. And it is compulsory to remove it.
The best way to eradicate musk thistles is by digging up the plants, ensuring that the long taproot gets removed. Never allow the plants to set seed!
(We’ve seen some homesteaders chuck them into a massive backyard bonfire. That’s right! They burn the seed heads before they can spread to the next generation of seedlings.)
4. Common Thistle / Spear Thistle / Bull Thistle (Cirsium vulgare)
Common thistle is undoubtedly the most weed-like of all thistle species – with its aggressive spiky appearance, not many gardeners would choose to keep this one for ornamental purposes!
Spear thistles can lie hidden for some time. They first grow a low rosette of leaves at ground level. Then, once the tap root fully establishes, the plant sends up a thick stem up to one and a half meters tall, covered in spiky leaves and purple flower heads.
Once established, spear thistles can be nearly impossible to eradicate. The plants must get cut or mowed before they set seed. And the deep tap root of each plant needs to get dug out to prevent it from regrowing.
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5. Purple Dead Nettle (Lamium purpureum)
I confess that I have a soft spot for purple dead nettle. In early spring, its delicate flowers will be bustling with bees coming out for their first feed after winter. However, if you give it half a chance, this dainty-looking plant will take over every available space on your plot.
Unlike stinging nettles, dead nettles form a low-growing mat over the ground, thriving in moist soil and partial sunlight. It is an annual plant that regrows every spring from seeds set the previous year.
While purple or red dead nettle does spread readily, it is not difficult to keep under control. Mowing or cutting the plants before they set seed will reduce the number of plants year after year.
6. Black Nightshade (Solanum nigrum)
Black nightshade is a broadleaved summer annual that bears purple or white flowers in the summer months, followed by bunches of red-purple berries. The stems of the black nightshade have a distinctive purple tinge.
Although black nightshade is an annual, it self-seeds prolifically and can soon become quite invasive. The easiest way to control it is by pulling the plants by hand before they go to seed.
Black nightshades are in the same family as deadly nightshade. It is not as poisonous as its poisonous relative. However, it does still have some toxic effects. When dealing with nightshades, it is best to wear gloves to protect your skin.
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7. Wild Violet (Viola Odorata)
An abundant display of wild violets is a beautiful sight, with a barrage of tiny purple flowers on a mat of dense dark green foliage. However, a little corner of wild violets can quickly spread, taking over your entire lawn!
Wild violets propagate using rhizomes – thick underground stems from which multiple plants can grow. Sadly, unless you want to use chemical herbicides, the only way to eradicate wild violets is to dig up every plant by hand.
However, they can be excellent ground cover in shady areas where grass will not thrive, so it is worth establishing a patch of wild violets elsewhere in your garden.
8. Forget-Me-Nots (Myosotis sylvatica)
Forget-me-nots are a beloved border plant for many gardeners. However, in some Midwestern states, they have reputations as a noxious weed! Their questionable distinction is because these lovely little plants can self-seed prolifically, quickly taking over your plot.
With its myriad of tiny purple-blue flowers, forget-me-not is instantly recognizable. While it makes a great filler plant for a flower border, it is essential to dead-head the plants before they set seed to prevent them from spreading.
9. Dove’s-Foot Cranes-Bill (Geranium molle)
Dove’s foot cranesbill is a member of the hardy geranium family and thrives in poor-quality soil. It will quickly establish itself in poorly growing lawns, crowding out grasses. It spreads rapidly via its exploding seed pods which scatter seeds over a wide area.
If the dove’s-foot crane’s-bill has invaded your lawn, the best management strategy is to mow the lawn and remove the clippings. Avoid putting the clippings on your compost heap. Doing so may aid the spread of the dove’s foot cranesbill elsewhere in your garden.
10. Purple Loosestrife (Lythrum salicaria)
Purple loosestrife is not native to the United States. It got accidentally introduced in the early 19th century. Purple loosestrife then spread rapidly across the country! And in some states, it has had a hugely detrimental effect on native flora.
This plant grows between 30 and 50 upright stems from a single horizontal rhizome, which can grow to over 2 meters tall. It produces clusters of tiny purple flowers on long flower spikes at the top of each stem.
Since purple loosestrife is an invasive plant, it should not be grown in gardens. A single plant can produce over 2 million seeds yearly, so you can see how quickly it might make itself at home in your yard! Any existing plants should get dug up and disposed of in the garbage.
11. Common Self-Heal / Heal-All (Prunella vulgaris)
Self-heal is another member of the mint family that gets its name from its reported medicinal properties. However, while it could work wonders for your health, this plant will rapidly take over any area it gets planted.
If you want to keep a small patch of self-heal in your garden, it is best to grow it in a pot or container and trim the plant back after it has flowered. Avoid letting the longer stems of large self-heal plans fall against the ground, as they will quickly take root in any available nook and cranny.
Like many purple weeds, self-heal is a good choice for a wildflower meadow, where it will not have the space and nutrients to spread as vigorously.
Thanks for reading our list of weeds with purple flowers.
We hope we conveyed that not all of these weeds are noxious!
Some purple weed flowers can help attract beneficial pollinators – such as honeybees, songbirds, and butterflies.
We think hosting some of these breathtaking flowers can help your garden. (Except for toxic belladonna flowers and their relatives. We’re not fans of those!)
In any event – thanks again for reading.
And if you need help identifying unknown weeds with purple flowers? Let us know!
Our team has many decades of accumulated garden experience. And – we always love helping our fellow homesteading friends.
We hope to hear from you.
Have a great day!