It does not take much for weeds to survive. Hence, they are everywhere, including your plants and crops. They take up space and consume the water and nutrients your plants and crops need, which affects their growth and health.
Whether you want to keep or remove these weeds depends on whether they cause enough damage despite their beauty. You need to identify them first to understand how much damage they cause. So, here are 20 purple flowers on weed with tips for eradication.
1. Wild Violet
Wild Violets are low-growing perennials with bright-eyed purple flowers that bloom in mid-May. They grow in small patches in moist, shady sites and expand annually.
Some gardeners consider them ornamental plants, but others find them irritating because of their uncontrollable and aggressive behavior. They do not need to bloom to reproduce and quickly take over a lawn.
Once they do so, it is difficult to eradicate them because their waxy leaves are resistant to many common herbicides.
Control Tips
The best way to eradicate them is to prevent them from spreading quickly. You should remove every bit of their roots by hand when the invasion is small, or you could use herbicide frequently.
To get the herbicide to work, mix in a tablespoon of dish soap for a gallon of spray. Well-maintained turf grass is also a great defense.
2. Ground Ivy
A common lawn weed, ground ivy, or creeping Charlie can survive in most weather and terrain. They bear bluish-purple flowers that have lobe-shaped petals and unique scalloped leaves. These flowers bloom in the late spring to early summer.
Creeping Charlie blankets your lawn, competes for nutrients with other plants, and destroys them. It is difficult to kill them because they can easily survive the lawnmower.
Control Tips
They must be eradicated when they start appearing because they are resilient against herbicides and chemicals. You should be vigilant and dig or pull out their roots the moment you see them but the most effective way to combat ground ivy is to maintain a healthy lawn that can outgrow the invasive plant.
3. Creeping Jenny
Creeping Jenny is a perennial herb of the primrose that grows in warm climates. It is sometimes confused for Creeping Charlie because of their similarities, but you can tell them apart from the color of their flowers.
Creeping Charlie has purple flowers, while Jenny has yellow flowers, and the leaves are not scalloped.
Control Tips
Creeping Jenny is sometimes grown as an ornamental because it grows into a pretty groundcover for shady, wet conditions. However, they are very invasive and a pain to get rid of.
The best way to control their spread is to remove the plant physically. Take a flat, sharp spade and cut out plants from underneath manually. Then, cover these areas with thick organic mulch to discourage re-growth.
4. Purple Dead Nettle
Dead nettle (Lamium purpureum L.) is actually part of the mint family and not the family of nettles, a type of plant that stings the skin. It has upright 4-sided stems with red and purple triangular leaves with purple-tinged foliage. It bears flowers of a pale pinkish-purple color with a few purple streaks and spots.
Control Tips
Hand-pulling and regularly mowing your lawn at a typical height of 2 to 3 inches in early spring, focusing on removing the flower stems can help control their spread.
Increasing turf density through proper fertilization and selecting turfgrasses that can adapt to the site conditions well also helps. Lastly, you can use various post-emergence herbicides.
Henbit is another purple flower weed. It is not as common as the other weeds in this list. They are often mistaken for purple dead nettle. Both have small purple flowers that appear in the axils of the upper leaves, but other than that, they are different.
Henbits droop more than the purple dead nettle and do not grow as high. Their leaves also have a hairy appearance, and the flowers can be purple, pink, or white.
Control Tips
They do not typically take over your garden, but the best way to discourage their spread is a dense lawn. With proper fertilization and mowing, a healthy lawn will out-compete henbit.
6. Chicory
Chicory is a perennial herb that bears dazzling periwinkle-blue flowers usually close by noon, and their color will fade to white. It blooms from mid-summer through fall and can grow to 1 to 3 feet tall. Chicory forms a taproot and grows from basal leaves that may be green or red.
Young chicory leaves are a food source for livestock, but as they mature, they become leafless and spread uncontrollably, choking out other plants.
Control Tips
Unlike most weeds that can be controlled by mowing, chicory is unaffected. They need to be controlled by hand pulling and hoeing.
Hoeing or hand-pulling the tap root is more effective and should be done before the formation of seed heads.
7. Cat's Ear
Cat’s Ear, or flatweed, is a low-lying perennial commonly found in parks, gardens, footpaths, lawns, roadsides, disturbed sites, and waste areas. This plant has leaves
that are lobed, 20 cm long, and covered in coarse hairs reminiscent of a cat’s ears, hence the name. They bear bright yellow flowers similar to a dandelion on forked stems that exude a milky sap when cut.
Control Tips
Cat’s Ear is not toxic, but once established, it forms thick roots that are difficult to remove and control. If you want to rapidly desiccate this weed, Bioweed, an organic, non-selective weed killer, might be effective. It breaks down into the soil within three days and can combat over 200 invasive weed species.
8. Clover Dodder
Clover Dodder is a parasitic plant that belongs to the Convolvulaceae (Bindweed) family. It has hairless, thread-like yellow, red, or purplish-colored stems that twine over vegetation.
This plant bears clusters of stalkless, purplish flowers with petals that form a cup shape and small scale-like leaves. It lacks chlorophyll and depends on its host plant for its supply of nutrients.
Control Tips
Hand removal and pruning are usually sufficient to control the growth of this weed. You can manage small infestations of dodder by cutting off host plants 1/8 to 14 inches (5 mm. to 36 cm.) below the point of attachment.
You can manage large ones by mowing or spraying pre-emergent herbicides to thwart seed production.
9. Field Pansy
Field pansy (Viola arvensis) is a low-growing annual weed that grows in fall and spring. It has attractive pale yellow to purple flowers, each with five petals and sepals, and smooth, hairless rosette leaves with small notches around the edges. Despite the plant’s pretty flowers and leaves, people want to remove it.
Control Tips
Field pansy is difficult to control, and the standard method of applying glyphosate in the spring is ineffective. Instead, applying herbicides during fall provides better control of field pansy. A single glyphosate application in the fall can prevent their spread.
Common lantana is a rapidly growing weed with a scrambling shrub that grows up to 4m tall and occasionally grows like a vine. They have hairy stems with short prickles and are usually green in color but turn gray or brown as they mature.
They bear small tubular flowers in a wide variety of colors, including white, cream, yellow, orange, red, pink, and purple.
Control Tips
Lantana is toxic to livestock and humans and needs to be removed. If they are in your garden, pulling them out by hand is enough to control their spread. Wear gloves and long sleeves while doing so, as it irritates the skin and causes rashes. But if the lantana has taken stronger roots, biological control may help.
11. Buckhorn Plantain
Buckhorn plantain is a cool-season broadleaf weed that spreads by seed. The plant forms a spreading basal rosette of narrowly oval bright to dark-green leaves that grow above a dense network of taproots with lateral branches. It has a cone-shaped seed head with cylinder-shaped small white to brown flowers.
Although these plants are not toxic to livestock, they can be difficult to control. Therefore, prevention is essential in managing this weed.
Control Tips
Healthy plants will shade the soil surface, making it difficult for buckhorn seedlings to establish. Also, you should be on the lookout for these weeds and eradicate them early on.
Heavy grazing and clipping are more effective than hand removal as it is a low-growing weed. You can also use herbicides.
12. Common Burdock
The most unique purple weed grass you will notice is perhaps the common burdock. It is a biennial weed with a basal rosette and large, hairy, and heart-shaped leaves.
As the plant matures, it produces a coarse, multi-branched, upright stem that grows 10 feet tall. At the end of these branches are numerous, clustered pink to purple flowers that debut from mid-summer through fall.
Control Tips
If the burdock plants are small, pull them out manually, but for large ones, carefully dig them up and remove the entire tough taproot.
If you cannot remove the burdock immediately, you can prevent it from spreading by removing the flowers before they go to seed.
13. Forget-Me-Nots
Forget-me-nots are famous for their blue flowers with yellow centers, but they also come in a purple variety. Gardeners include them in their gardens intentionally because of their striking features and ease of care.
However, if they are not looked after properly, they will spread quickly and outgrow other plants and destroy them.
Control Tips
Forget-me-nots can be removed by hoeing or cultivating the soil, especially in small numbers. However, the plants resprout if you do not remove the roots, so make sure you pull or hoe the plants before they go to seed.
If this does not help and you are out of options, you can use herbicides as a last resort. They are effective when the weed patch is large and uncontrollable.
14. Dove's-foot Cranesbill
The dove’s-foot crane’s-bill might be one of the weeds that probably does not need to be removed. A widespread invasion of your garden is still possible, but because it prefers arid conditions and dry soil, which many plants do not, they might not survive easily.
These plants have unique purple flowers with jagged petals that add color and texture to your landscape. Just make sure they do not take over your garden.
Control Tips
You can leave this weed alone if you want it for ornamental purposes. If not, you can remove them by pulling them up. Also, ensure your lawn is well cared for, moist, and full of nutrients.
Another purple weed on this list is Canada thistle or the creeping thistle. The weed flowers purple blooms in clusters in teardrop shapes. The flowers grow during the middle of summer on top of 3- to 5-foot-tall stems. These weeds grow anywhere, and there is no reason for you to keep them in your garden.
Unfortunately, they are infamous for being difficult to eradicate, but this does not mean it is impossible.
Control Tips
These weeds grow best in low-fertility soil, so increasing your soil's fertility will increase your chances of eradicating them. You can also pull them, but this might be laborious due to their extensive root system.
Alternatively, you could use a non-selective herbicide or clip off their flowers before they mature and set seed.
16. Bull Thistle
Another thistle on this list is the bull or spear thistle. These plants germinate in spring and fall and can be identified by their large pink to purple flower heads with spines around the base and long leaves covered in barbs.
These flowers bloom from June to October, and their seeds cause their spread. They spread quickly to form dense patches and crowd out grasses. When not controlled, they can take over your garden and pasture.
Control Tips
To effectively manage bull thistle, it's crucial to prevent the plant from producing seeds. The seeds germinate quickly in the spring and fall, and those on the surface only survive for a year.
Buried seeds survive up to three years. You can manually, culturally, mechanically, and chemically control the spread of the seeds. Choose the method you think is the most suitable.
17. Black Nightshade
Black Nightshade is another prolific and troublesome weed. They are identifiable by their upright, mostly hairless purplish/green stems, purple flowers with a yellow column in the center, and purple or red berries that grow in bunches.
Black Nightshades grow in a wide range of soils but thrive in nitrogen-rich soil. They can grow like vines or in clusters like a bush.
Control Tips
You can control these weeds by pulling them by hand and prevent their spread by covering the soil with mulches, such as bark, wood chips, leaves, and other organic material, to preserve moisture and improve the condition of the soil.
18. Bugleweed
Carpet, or common bugleweed, is a perennial weed and part of the mint or Lamiaceae family.
You can easily recognize it by its purple spiky flowers and glossy, dark-green leaves on square flower stems with yellowish-green to green or purplish color.
This weed grows year-round in warm climates but may die and emerge in spring in colder climates. It spreads via stolons, which creates a dense, fast-spreading ground cover.
Control Tips
The best way to manage bugleweed without using chemicals is hand pulling.
Water the area a day before and loosen the soil around the weed so that it is easier to pull out. Remove as many roots as possible and dispose of the plant properly.
Another option is homemade herbicide made of equal parts boiled water and vinegar. Apply the mixture with a garden spray.
19. Blue Vervain
Blue Vervain is a perennial herbaceous plant that may grow and thrive in polluted areas. It has distinguishing features like 4-angled stems with fine white hairs and pencil-like purplish-blue flower spikes that branch upwards, reminiscent of a candelabra. Its lance-shaped leaves are strongly veined and have toothed margins.
Depending on the geographic location, blue vervain blooms anywhere from late spring to late summer and lasts almost two months.
Control Tips
If you are looking to get rid of it, you can use black plastic. Smother the weed patches with black plastic for two weeks so the sun can dry out the weed, and if they are still alive, leave the plastic for another two weeks.
20. Heal-All
Heal-All is a creeping perennial weed commonly found in turfgrass, lawns, and occasionally along roadsides and in pastures and hayfields. It is also referred to as a herb because it was used as medicine traditionally.
It has smooth square stems with purple, tube-like flower clusters at the end and long, straight leaves with rounded tips along the stem.
Control Tips
Heal-All has a long lifespan and is very difficult to eradicate. You should remove its entire root system to prevent re-growth, which could take several seasons. Spray herbicide and hand-pull the roots till the plant is eradicated.
