Purple flower weeds are a diverse group of invasive, often fast-spreading plants that thrive in gardens, yards, lawns, or agricultural lands. They often cause a lot of headache due to their fast growth and negative impact on desirable plants, despite their vibrant and often attractive flowers. They impede the growth of native vegetation by outcompeting them for resources like water, nutrients, and sunlight.
The small purple flowers in your grass are most probably Wild Violet, Purple Dead Nettle or Henbit.
While you want to get rid of most weeds with purple flowers, some of these plants like Wild Violets or Creeping Charlie/Ground Ivy are also appreciated for their beauty and you can use them as ground cover or natural pest control.
In this article, you will learn what the most common weeds with purple flowers are called, how to identify them (with pictures), and how to control them. We will discuss the following plants:
- Wild Violets (Viola odorata)
- Purple Dead Nettle (Lamium purpureum)
- Henbit (Lamium amplexicaule)
- Creeping Charlie/Ground Ivy (Glechoma hederacea)
- Forget-Me-Nots (Myosotis)
- Black Nightshade (Solanum nigrum)
- Canada Thistle/Creeping Thistle (Cirsium arvense)
- Musk Thistle/Nodding Thistle (Carduus nutans)
- Common Thistle/Spear Thistle/Bull Thistle (Cirsium vulgare)
- Dove’s-Foot Crane’s-Bill (Geranium molle)
- Selfheal/Healall (Prunella vulgaris)
1. Wild Violet (Viola odorata)
Wild Violets possess heart-shaped leaves that typically form a basal rosette, meaning all leaves and flowers arise from a central point near ground level. The most distinct feature of Wild Violets is their flowers. They primarily bloom in purple-blue hues, but certain varieties also produce yellow or white flowers. These flowers are often scented, adding to their charm.
Wild Violets reach a height of 4-6 inches (10-15 cm) and can spread between 8-24 inches (20-61 cm) across when fully mature. They commonly grow in yards, gardens, and the borders of forests, especially in the northern regions of the United States.
While Wild Violets are edible, rich in vitamins A and C, and boast medicinal qualities due to their rutin content, they may become problematic due to their invasive growth habit. They can quickly take over lawns and flower beds, as they spread through both seeds and rhizomes. To control these resilient perennials, consider herbicides containing glyphosate, dicamba, triclopyr, 2,4-D, or MCPP, ideally applied in fall. Alternatively, less harmful methods like manual weeding or natural remedies using horticultural vinegar and water can be effective, albeit labor-intensive.
2. Purple Dead Nettle (Lamium purpureum)
Purple Dead Nettle is an annual plant that typically grows up to 10 inches (25 cm) in height. It’s characterized by its square stems, triangular to heart-shaped leaves, and small, purple-pink flowers that bloom in whorls around the stem.
The plant gets its name from the purplish hue that the leaves often take on, especially those toward the top of the plant. Despite its name, it’s not a true nettle and does not sting.
Purple Deadnettle, while offering medicinal and nutritional value, can be a nuisance due to its invasive growth pattern. Its leaves can be consumed or used for medicinal tea, providing antioxidants for health improvement. It also possesses antimicrobial properties, serving as a remedy for open wounds.
Despite these benefits, its aggressive growth often leads to unwanted domination in gardens, especially in areas with thinning turf. To control Purple Deadnettle, don’t till the soil in fall or winter, or consider using herbicides with 2,4-D, dicamba, or fluroxypyr. A preventative approach involves maintaining a healthy, dense lawn, effectively limiting Purple Deadnettle’s spread.
3. Henbit (Lamium amplexicaule)
Henbit is a low-growing, annual plant that typically reaches heights of 4 to 12 inches (10-30 cm). It features square, hollow stems and rounded, lobed leaves often clasped around the stem, giving the plant its species name, ‘amplexicaule’, which means ‘clasping’.
The flowers of Henbit are small, tubular, and typically pink to purple. They bloom in whorls around the stem in the early spring.
Henbit, an annual broadleaf plant, typically thrives in cultivated fields, lawns, and pastures. While it provides nectar to spring pollinators and possesses edible, nutritious, and medicinal qualities, it’s a highly invasive species that can deprive turfgrass of nutrients. With a sweet, peppery flavor akin to celery, it is high in iron, fiber, and antioxidants, offering anti-inflammatory and wound healing properties.
However, Henbit can cause a lot of headache as it’s capable of producing up to 2,000 seeds per plant. To manage Henbit, promote lawn health with sufficient drainage and sunlight, mow to the correct height, and cultivate a thick turf to deter weed competition. Utilizing post-emergent or pre-emergent herbicides can also be effective, with hand weeding as a solution for smaller infestations, given the entire plant and root system are removed.
4. Creeping Charlie / Ground Ivy (Glechoma hederacea)
Creeping Charlie is known for its scalloped, kidney-shaped leaves that grow in pairs opposite each other along the square, trailing stems. The leaves are rich, dark green but can also present purplish hues in cooler temperatures.
The most distinctive feature of Creeping Charlie is its small, funnel-shaped flowers. The blooms are typically lavender or blue-violet, appearing in clusters in the late spring. The plant emits a strong minty aroma when crushed or mowed, a telltale characteristic of this species.
Creeping Charlie exhibits a vigorous growth habit, reaching a height of approximately 2 inches (5 cm), but spreading outwards up to 3 feet (90 cm) or more. It propagates by seeds and the creeping stems, which root at the nodes(2).
Creeping Charlie has a distinct minty aroma when crushed, this plant has been valued in cooking and medicine for centuries, being rich in vitamin C and a flavorful addition to soups. However, it’s toxic to livestock such as horses, swine, and cattle.
Its invasive growth habit, especially in moist, shady areas, makes it a concern for gardeners. It tends to overtake landscaping beds and lawns, eliminating other vegetation due to its low-lying, vining growth pattern. Control methods include improving water drainage, reducing watering to dry the soil, or increasing sunlight exposure. Post-emergent herbicides containing dicamba salts or triclopyr can be effective, with hand weeding a viable option for minor infestations, provided the entire plant and root system are removed.
5. Forget-Me-Not (Myosotis)
Forget-me-nots are delicate flowering plants from the genus Myosotis, with the name derived from the Greek for “mouse’s ear,” a reference to their small, soft, oval leaves(3).
Forget-Me-Nots are most recognizable for their abundant, tiny flowers that bloom in captivating shades of blue with yellow or white centers. The blossoms typically form clusters, presenting a spectacular floral display in the spring and early summer.
The plants generally grow to a height of around 6-12 inches (15-30 cm) and spread out horizontally, with their thin, hairy stems growing in a somewhat sprawling manner. Their leaves are alternate and oblong, with a slightly hairy surface.
Forget-Me-Nots bring charm with delicate blue flowers, offering beneficial pollen to bees and butterflies. However, they are prolific seeders and can overwhelm garden space. They’re generally seen as an attractive nuisance. Pulling up the plants before they seed is the best way to control them.
6. Black Nightshade (Solanum nigrum)
What Does Black Nightshade Look Like?
Black Nightshade plants are annuals or short-lived perennials that typically grow up to 1-2 feet (30-60 cm) tall. They have simple, ovate leaves and white to purplish, star-shaped flowers that develop into round, black berries when mature.
The plant’s stems are generally semi-woody at the base, and its leaves, while mostly entire, may have few to several coarse teeth.
Black Nightshade has some medicinal uses as it has been employed in the treatment of skin conditions, fever, pain, and other ailments. However, its berries and leaves are toxic, posing risks to children and pets. It’s generally suggested to eliminate it. Manual removal, ensuring you get the root, is effective.
7. Canada Thistle (Cirsium arvense)
Canada Thistle, lso known as Creeping Thistle, the Cirsium arvense is a species of thistle in the Asteraceae family.
Canada Thistle is characterized by its tall, erect stems that can reach heights of 1-4 feet (30-120 cm). The stems are winged, with spiny, alternating leaves, and are topped with clusters of small, lavender to pink flowers. These flowers are tubular and bristly, typical of plants in the thistle group.
The plant features an extensive root system, which allows it to spread aggressively, often forming dense colonies. The roots can extend horizontally up to 15 feet (4.5 meters) and vertically up to 20 feet (6 meters).
Canada Thistle has pollinator-friendly flowers, but its aggressive, spreading roots make it a gardening nightmare. Eradication is preferred. Regular mowing or grazing before it seeds can control it.
8. Musk Thistle (Carduus nutans)
Musk Thistle, also known as Nodding Thistle, is a biennial flowering plant that belongs to the Asteraceae family.
The Musk Thistle is known for its striking, large, purple flowers that ‘nod’ or hang to one side, hence the name Nodding Thistle. The flower heads are typically 1.5 to 3 inches (3.8 to 7.6 cm) in diameter and bloom from late spring to early summer.
The plant features large, deeply lobed, spiny leaves that form a rosette in the first year, before sending up a tall flowering stem in the second year. The plant can grow up to 7 feet (2 meters) in height.
Musk Thistle is a nectar source but considered an invasive species due to its rapid spreading nature. It should be removed. Cutting the flower heads off before they seed can limit its spread.
9. Common Thistle (Cirsium vulgare)
Common Thistle is a tall, biennial plant that can reach heights of 1 to 5 feet (30-150 cm). The plant forms a rosette of spiny, lobed leaves in its first year. In the second year, it sends up a tall, branched stem with smaller, more pointed leaves, topped by a cluster of purple, thistle-like flowers.
The plant’s stem and leaves are covered in sharp spines, which provide the plant with its common names of Spear Thistle and Bull Thistle.
Common Thistle attracts pollinators but is prickly and invasive. It’s advised to remove it. Regular mowing prevents it from seeding and controls its spread.
10. Dove’s-Foot Crane’s-Bill (Geranium molle)
Dove’s-Foot Crane’s-Bill is a low-growing, annual, or biennial species that usually grows to 4-12 inches (10-30 cm). It features softly hairy stems and leaves, which are deeply divided into 5 to 7 lobes, giving them a somewhat feathered appearance.
Dove’s-Foot Crane’s-Bill is known for its pink to purple flowers with five petals each. These flowers, which bloom from spring to fall, are followed by fruit that resembles a crane’s bill, hence the plant’s common name.
Dove’s-Foot Crane’s-Bill can tolerate poor soil, but it’s an aggressive spreader. It’s typically removed. Hand-pulling the weed is an effective control measure.
11. Selfheal (Prunella vulgaris)
Selfheal, also known as Healall or Prunella vulgaris, is a perennial herbaceous plant that belongs to the Lamiaceae, or mint, family.
Selfheal is a low-growing plant that usually reaches a height of 4-12 inches (10-30 cm). Its square stems are characteristic of the mint family, and its leaves are lance-shaped and arranged oppositely along the stem.
Selfheal is most recognizable by its flowers, which are small, tubular, and usually a vibrant purple color. These flowers bloom in a dense, cylindrical cluster, or spike, at the top of the stem from late spring through fall.
Selfheal (Prunella vulgaris) has medicinal uses but can overrun lawns. It’s typically eradicated. Mowing high can help grass compete against it.
