Yellow flowers may bring joy and beauty to various outdoor spaces like borders, rock gardens, and flower beds. However, when it comes to lawns, their impact is less pronounced. You might find yourself dealing with unwanted black-eyed Susans or dandelions sprouting up everywhere, prompting the urge to eradicate them and restore your lawn’s original appearance. In reality, these small yellow blooms can be a nuisance in your yard.
To tackle this issue, we’ll delve into some common weeds featuring tiny yellow flowers, explore their effects on your outdoor space, and offer practical advice for removal.
Canada Goldenrod
The Canada goldenrod stands out due to its unique flower appearance, which resembles pyramidal stems covered in millions of tiny, hairy blossoms. The plant’s leaves are a deep green color, with a toothed and lanceolate shape that narrows towards the base. While it can grow up to 6 feet tall, it typically reaches a height of 2-4 feet. The Canada goldenrod’s seeds are lightweight and easily dispersed by wind, allowing them to quickly germinate.
Unfortunately, this means they can outcompete your grasses and other floral cultivars, ultimately suffocating or overcrowding them. The plant’s size can also significantly impact the appearance of your lawn. To manage Canada goldenrod growth, use weed killers containing triclopyr to eliminate any young plants you notice on your grass. However, it’s essential to note that this herbicide can cause damage to regular grass species in warm climates like Florida.
Therefore, be sure to overseed after application.
Butterweed
The butterweed’s visual appeal is undeniable, with its bright yellow petals and deeper orange or yellow discs making a striking impression. Its leaves initially have smooth edges, but as they mature, they develop lobed shapes. This plant can grow up to 3 feet tall, but it’s crucial to note that it’s highly toxic to cattle and horses, posing a fatal risk if ingested.
The butterweed is native to North America, where it can spread aggressively, outcompeting other plants for resources.
Moreover, its toxicity extends beyond livestock, posing a threat to humans who ingest it or pets who accidentally consume it. As such, eliminating this plant from your lawn is the most effective solution.
When it comes to controlling the butterweed’s growth, 2,4-D proves an effective treatment option when applied during the flowering phase. However, repeated applications may be necessary to achieve desired results.
Black Medic
The black medic plant, a member of the legume family, boasts trifoliate oval leaves and globe-shaped flower heads that resemble those of clover. Its growth habit is typically short-lived or annual perennial, reaching heights of 1-2 feet. Notably, this plant outcompetes lawn grass due to its extensive deep taproot, which also inhibits the germination of surrounding grass seeds, often resulting in unsightly patches. The black medic grows aggressively and is a non-native species.
One of its most notable characteristics is its challenging root system, making it difficult to eradicate using traditional methods. Instead, consider employing post-emergent herbicides containing fluroxypyr, MCPP, and dicamba to curtail its growth. Proactively maintaining a healthy lawn through proper fertilization, watering, and mowing can also help prevent the black medic from gaining a foothold.
Black-Eyed Susan
Black-eyeds Susan, a smaller cousin of sunflowers, thrives in flower beds, growing 1-3 feet tall or up to 4-6 feet for some varieties. Its bright yellow blooms feature dark centers surrounded by narrow, ovate leaves. While not considered invasive, this plant exhibits aggressive growth and can quickly dominate your yard, potentially disrupting a well-manicured lawn. To maintain control, remove spent flower heads before they produce seeds, thereby preventing propagation.
Additionally, uproot the entire plant, including rhizomes, as even small fragments can regenerate new plants.
Bird’s Foot Trefoil
The bird’s foot trefoil may seem charming with its tiny yellow flowers dotting various spots, but it’s a different story when they start sprouting up on your lawn. The plant’s oblanceolate leaves boast smooth edges, and its low-growing habit reaches heights of 1-2 feet. What’s more, the bird’s foot trefoil has a knack for spreading via stolons and rhizomes, self-seeding with reckless abandon.
This invasive weed can choke out grass and other plants, making it a nuisance to deal with in many parts of North America. As such, it’s essential to take proactive measures to eliminate it from your lawn.
To prevent the bird’s foot trefoil from gaining a foothold, focus on maintaining healthy soil conditions by ensuring proper irrigation, fertilization, and mowing habits. A well-cared-for lawn can grow aggressively, outcompeting weeds like this one.
If these measures don’t prove effective, you may need to resort to using herbicides containing 2,4-D, MCPP, or dicamba to eradicate the problem.
Common St. John’s-Wort
The distinctive features of St. John’s-wort include its star-shaped flowers, which feature numerous stamens that resemble sun rays. The plant’s smooth, elongated leaves are another notable characteristic. Measuring 3-6 feet in width and reaching heights of up to 6 feet, it can be quite a presence in the landscape. This invasive species propagates through seeds and underground rhizomes, producing an astonishing 34,000 seeds per year.
As such, it has the potential to spread rapidly and cause harm to animals, resulting in skin lesions, dead tissue, and other health problems. To prevent St. John’s-wort from taking over, maintaining a healthy lawn is crucial. This can be achieved by regular mowing, watering, and fertilizing of your grasses. If you do encounter the weed, removing individual plants can be effective, but larger infestations may require the use of herbicides containing metsulfuron or 2,4-D.
Common Ragwort
Ragwort, a member of the daisy family, boasts an attractive appearance due to its short stems supporting pinnate and lobed leaves, accompanied by numerous yellow flowers. The common name ‘stinking willie’ provides a stark reminder why many people seek to eradicate it. This invasive weed can grow up to 30 inches in height.
One of the primary concerns with ragwort is its toxicity, which poses a risk to livestock such as pigs, chickens, horses, and cattle.
Its rapid seed production, yielding thousands of seeds within 4-6 weeks, allows it to spread swiftly across your yard, making it essential to take prompt action.
To prevent the weed from seeding and spreading, mowing it before flowering is a effective strategy. If the plant is confined to a specific area, manual removal by pulling out the entire root system can be a viable option. Alternatively, plowing or using herbicides with 2,4-D or MCPP can provide more comprehensive solutions.
Common Evening Primrose
The common evening primrose is characterized by its bright lemon-yellow, bell-shaped flowers that undergo an intriguing cycle. As the day transitions into night, the flowers unfurl and remain open until morning, only to close once the heat returns. This adaptable plant can grow up to 2-6 feet in height and features long, narrow leaves that line its stem. While it may not be a typical nuisance weed, the evening primrose has a knack for self-seeding and spreading rapidly.
In fact, mowing won’t prove effective against this persistent invasive as it can multiply through underground rhizomes. As the plant’s size becomes more pronounced, it’s likely to disrupt the aesthetic appeal of your lawn, prompting you to either eradicate it entirely or relocate it to a designated flower bed. To effectively manage this weed, consider targeting it before it blooms, thereby preventing self-seeding. Next, carefully remove the entire root system to prevent regrowth.
For larger infestations, broadleaf herbicides can be employed as a treatment option.
Creeping Cinquefoil
The creeping cinquefoil’s most striking feature is its yellow heart-shaped petals, which form a cup-like structure. While not particularly noteworthy on their own, they do add some visual interest to the area. However, it’s the plant’s leaves that are more likely to cause issues with lawns. The oblong, deep green leaves are toothed and can quickly overgrow your grass if left unchecked.
Fortunately, the creeping cinquefoil only grows up to 6 inches tall, giving you a chance to remove it before it becomes a problem. But don’t be fooled – this plant is a master of invasion. It spreads rapidly through runners that root quickly, allowing it to cover large areas in no time at all. As an invasive species, the creeping cinquefoil will do its best to suffocate other plants and take over your yard if given the chance.
To keep the creeping cinquefoil under control, focus on creating conditions that favor grass growth through proper lawn care. This includes regular irrigation, mowing, fertilization, and aeration. If you need to eliminate the plant entirely, be prepared for a challenge – it has deep roots that can make removal difficult. However, herbicides containing dicamba, 2,4-D, and other chemicals can provide an effective solution.
Creeping Buttercup
The creeping buttercup’s distinctive triangular or egg-shaped leaves and bright yellow cup-shaped flowers make it a formidable foe in the battle to maintain a pristine lawn. Despite its relatively modest height of 1.5 feet, the plant can still be detected among the blades of grass, making it all the more challenging to eradicate.
Its ability to compete with lawns for essential nutrients like potassium, as well as its propensity to spread via stolons and seeds, make it a significant threat to your lawn’s health and appearance. As such, it is crucial that you take proactive steps to prevent this weed from gaining a foothold, lest it tarnish the beauty of your green expanse and put it at risk of decline. Effective management strategies include the use of post-emergent herbicides containing aminopyralid, MCPA, or 2,4-D.
Cypress Spurge
The cypress spurge’s unassuming appearance belies its aggressive nature: it can grow up to 12 inches tall and spread quickly by seed or rhizome. This weed’s most notable features are its bright yellow flowers and light green leaves, which, while not the most aesthetically pleasing, do little to deter its eradication. In fact, the cypress spurge is considered a nuisance due to its latex sap, which can cause blindness and skin irritation in humans and animals alike.
Its tendency to suffocate native grasses and plants only adds to its unwanted reputation.
While the cypress spurge may thrive in poor and dry soils, regular lawn care practices can go a long way in keeping it at bay. Should you encounter this weed on your property, removal is an option, but be sure to excavate every rhizome to prevent regrowth from root remnants. Following up with a herbicide containing picloram, 2,4-D, dicamba, or quinclorac will ensure the job is done thoroughly.
Dandelion
Dandelions may seem harmless, boasting bright yellow blooms and wispy foliage that adds a touch of whimsy to your lawn. However, beneath their charming appearance lies a plant that can quickly take over, spreading its roots or seeds to dominate your entire grassy expanse. At 2-24 inches tall, they won’t suffocate your turf, but their clumpy growth habit can still leave you with an unsightly display if you’re particular about lawn aesthetics.
The good news is that dandelions’ aggressive spread can be mitigated by utilizing herbicides specifically designed for Bermuda grass. Formulations containing compounds like fluroxypyr, 2,4-D, and dicamba offer a targeted solution to eradicate these broadleaf weeds without harming your lawn’s integrity.
Golden Clover
The large hop clover, also known as the golden clover, is a non-native plant that can quickly take over your lawn due to its rapid reproduction. Its smooth, elliptic leaves and small, oval or round flowers can make it easily overlooked among the taller grasses. However, despite potentially attracting pollinators, the plant’s invasive nature means it can spread rapidly and cover large areas of your lawn. According to the Invasive Plant Atlas of the U. S.
, this species is indeed considered invasive. To effectively manage the golden clover, it’s essential to focus on promoting healthy, dense, and vigorous grass growth. This can be achieved through proper lawn care practices. If the infestation is minor, manually pulling out the plants can also be an effective solution. As a last resort, weed killers containing triclopyr or glyphosate can be used.
Nevertheless, it’s generally recommended to prioritize lawn maintenance and manual weeding over herbicide use, especially when dealing with residential landscapes.
Garden Loosestrife
Garden loosestrife, a plant known for its pyramidal flower heads featuring numerous bright or golden yellow cup-shaped blooms, can be identified by its egg-shaped or lanceolate leaves that typically occur in threes. This bushy plant typically grows to 2-3 feet tall, giving it an unmistakable appearance.
In terms of its impact, garden loosestrife spreads aggressively through rhizomes and seeds, with the former being the more critical method.
As a result, the plants can delve deep into the soil, making them notoriously difficult to eradicate completely. It’s not uncommon for the plant to appear to be growing stronger than ever after removal attempts.
Given its invasive nature, garden loosestrife can potentially overpower other plants on your lawn. To control their spread, consider digging and pulling out these weeds if they’re present in smaller numbers.
However, it’s crucial to remove the entire rhizome to prevent regrowth, as even the tiniest fragments can give rise to new growth.
In cases where the infestation is more widespread, herbicides containing compounds like imazapyr, triclopyr, and glyphosate may be necessary. It’s essential to follow proper application guidelines to ensure effective control of these pesky plants.
Grass-Leaved Goldenrod
The grass-leaved goldenrod is a distinctive plant with a disk-shaped flower head comprising numerous cylindrical flowers. Its foliage bears an uncanny resemblance to grass, despite its stems potentially bursting forth from your lawn even without golden blooms. Reaching 2-3.5 feet in height, the plants can be bushy or slender.
The plant’s primary means of propagation is through rhizomes, although its aggressive nature enables it to quickly take over a garden, especially when it receives ample sunlight. Furthermore, the root system and leaves of the goldenrod emit compounds that inhibit the growth of surrounding vegetation, gradually degrading your lawn as it spreads. In order to effectively eradicate this weed, consider employing herbicides or practicing proper lawn care.
For optimal results, use products containing 2,4-D, dicamba, and triclopyr, carefully following the manufacturer’s instructions on the packaging.
Lesser Celandine
The lesser celandine is a charming invasive species that presents itself with lotus-like leaves and star-shaped yellow flowers, which are unlikely to significantly mar your lawn’s appearance. Its relatively modest height of around a foot also means it won’t dominate the visual landscape. However, this unassuming plant has a knack for thriving in nutrient-rich environments and can tolerate shade, making it a formidable foe when it comes to eradication.
As it flourishes, it spreads through a combination of bulblets, tubers, seeds, and soil disturbance, outcompeting other plants in the process. To effectively remove this pesky plant, you’ll need to be prepared to sift through the soil, removing even the smallest root remnants. Alternatively, consider utilizing herbicides containing glyphosate and triclopyr to achieve a complete eradication.
Marsh Yellowcress
The marsh yellowcress, with its distinctive lobed foliage and four-petal flowers, can grow up to 2 feet tall. Despite its relatively short lifespan as an annual, it is able to spread quickly through seeds, potentially invading local habitats. However, it is not considered an invasive species, giving you the opportunity to eliminate it before it becomes a problem.
The plant’s shallow roots make it possible to hand-pull individual plants if the infestation is minor.
Simply ensure that you remove the entire root system to prevent regrowth. For more extensive problems, broad-spectrum broadleaf herbicides can be used effectively.
Skeletonweed
The skeletonweed earns its name due to its characteristic long and almost leafless stems adorned with strap-shaped flowers. While its slender appearance may be deceiving, it can grow up to 4 feet tall, spreading its branches extensively and ultimately compromising the aesthetic of your lawn.
This pesky weed has multiple methods of reproduction, including root shoots, root fragments, and seeds – making eradication a daunting task!
In the Southwest region, mature skeletonweed plants are considered invasive and can produce an astonishing 20,000 seeds.
To effectively contain this unwanted guest, it’s essential to take proactive measures. Thoroughly remove any root fragments you come across and maintain a healthy lawn to prevent skeletonweed infestation. If you’ve already got a mature plant on your hands, mowing it before it flowers will help prevent seeding.
For more extensive infestations, consider using weed killers containing picloram, 2,4-D, or similar agents.
Purslane
Purslane’s unique appearance is characterized by its small, heart-shaped flower heads that protrude from the fleshy leaves in the early morning. Despite its compact height of just three inches, the plant spreads significantly, reaching a width of around a foot and a half. What’s more astonishing is that one purslane plant can produce an impressive 240,000 functional seeds that remain viable for up to 40 years.
While seed dispersal is the primary means of spread, stem fragments can also propagate this invasive weed. The consequences of unchecked purslane growth are dire, as it can outcompete native plants and hinder pollinators and overall ecosystem diversity. To prevent purslane from taking hold in the first place, gardeners should prioritize sourcing supplies from reputable dealers and using clean equipment.
If an infestation does occur, effective control measures include covering the area with dark plastic or mulching to restrict photosynthesis. In extreme cases where herbicides are necessary, products containing MSMA, MCPP, dicamba, and 2,4-D can be used.
Sow Thistle
Sow thistle is a notable weed that stands out due to its towering height of 4-6 feet, significantly taller than its dandelion counterparts. The plant’s foliage also differs, featuring larger leaves with pronounced teeth that can be slightly prickly to the touch. When it comes to seed dispersal, sow thistle relies heavily on wind currents, a fortunate trait considering its seeds don’t remain viable for extended periods.
However, this invasive species has a dark side – it can choke out other plants and even prompted Alaska to ban it. For those looking to tackle the problem sans herbicides, manual removal is an option, albeit time-consuming and labor-intensive. Eradicating the roots is crucial, as simply pulling the plant up can result in regrowth.
Spanish Broom
While Spanish broom’s vibrant yellow blooms and bushy growth may initially seem appealing, it’s essential to consider its invasive nature. This noxious plant can cause gastrointestinal issues in animals and harm the environment if left unchecked. Its ability to spread quickly through seeds makes it a significant concern for small ecosystems. In fact, Spanish broom is considered an invasive species in North America, capable of causing severe damage given the opportunity.
If you’re dealing with a small infestation, manual removal by pulling and digging out the weeds may be effective. However, more severe cases will likely require the use of herbicides containing glyphosate and triclopyr for proper control.
Wild Radish
The wild radish’s visual characteristics are distinct from other plants. Its petals come in clusters of four, with a slightly oval shape, and are only loosely attached to the central flower head. The plant’s leaves also exhibit unique features – the top leaves are small and borne on short stalks, resembling miniature footballs with teeth-like edges, while the lower leaves are deeply lobed and egg-shaped.
In terms of impact, wild radish seeds can easily spread through contaminated hay or grain, facilitating its invasive nature. As an invasive species, it has the potential to outcompete native and beneficial plants, ultimately suppressing their growth. It’s also worth noting that wild radish is toxic to horses, according to the ASPCA. In order to effectively control this plant, herbicides are often the most practical solution, as they can provide long-term results while minimizing costs.
Products containing dicamba and 2,4-D are effective options, but it’s crucial to exercise caution when applying these chemicals to avoid inadvertently damaging your lawn.
Wild Parsnip
The Wild parsnip boasts an umbrella-like compound flower head, comprising numerous tiny flowers. Its soft, toothed, and deeply green leaves feature an unusual mitten shape, reaching heights of 1.5 to 5 feet tall. While it may not frequently infest lawns, stray seeds can still germinate, leading to invasion. This invasive species spreads its seeds rapidly, posing a threat to surrounding flora.
Furthermore, the plant contains a chemical that increases skin susceptibility to sunburn, emphasizing the importance of handling it with care. To curb Wild parsnip’s aggressive spread, consider mowing it down after blooming but before seed-setting. However, if the seeds have already been dispersed, employ a plastic bag to cover them, cut the flower heads, and properly dispose of the removed sections.
Wintercress
Wintercress, also known as yellow rocket, boasts a unique compound flower composed of numerous club-shaped blooms. Its leaves are oval in shape, but feature rounded lobes at their tips. Typically, the plant reaches heights between 12 and 25 inches. The real concern with wintercress lies in its ability to self-seed, producing an astonishing 10,000 seeds per plant. Left unchecked, this invasive weed can quickly spread across your lawn, requiring swift action to prevent it from taking over.
Furthermore, wintercress is toxic to horses, making prompt removal crucial. To regain control of the situation, you’ll need to take proactive measures against wintercress. The most effective approach involves digging up or mowing down the entire plant before it has a chance to flower. Alternatively, post-emergent broadleaf herbicides containing 2,4-D can be used to effectively manage this pesky weed.
Yellow Salsify
Yellow salsify is a plant that bears a striking resemblance to dandelions, but its leaves, situated near the flower, have a distinct star-shaped appearance rather than being rounded. The foliage itself has a grass-like quality, with a triangular shape setting it apart from other weeds. This plant rarely exceeds a height of three feet, making it a relatively small nuisance in most lawns.
In terms of spread, yellow salsify relies on seeds to propagate, with a single plant capable of producing up to 1,000 viable seeds that can be easily dispersed through the wind or by being blown across your lawn. Fortunately, this weed doesn’t have a significant impact on native ecosystems, nor does it consume excessive space or persist in any way. If you encounter yellow salsify, you can remove it by pulling out the entire plant, taking care to extract all roots to prevent regrowth.
Mowing isn’t necessary when dealing with yellow salsify, so you won’t need to alter your regular mowing routine. Should the infestation become more severe, you may consider using weed killers containing 2,4-D, dicamba, picloram, or similar compounds.
Yellow Nutsedge
Yellow nutsedge is a deceivingly grass-like weed that can quickly go unnoticed until it’s taken over your lawn. Its distinctive triangular-shaped flowering stalks, adorned with thin wheat-like blossoms, can reach heights of 3 feet, making it difficult to ignore. While the plant’s growth is facilitated by its ability to spread through rhizomes, its seeds are notoriously finicky and rarely germinate, earning it a reputation as an invasive species.
In order to effectively manage this weed, it’s crucial to identify it early on, as manual removal methods are ineffective once it has established itself. Instead, utilizing weed killers containing sulfentrazone and halosulfuron is the most practical solution for controlling cool-weather grasses infested with yellow nutsedge.
Yellow Hawkweed
Yellow hawkweed, often mistaken for dandelions due to its similar appearance, stands out with its uniquely tall growth habit, reaching up to 3 feet in height. Its stems branch upwards and produce golden flowers, but the plant’s foliage is typically absent. This distinguishing feature sets it apart from other weeds. The yellow hawkweed multiplies rapidly through seeds, rhizomes, and stolons, making it a formidable opponent when it comes to controlling its spread.
Although it can be invasive, the good news is that it is non-toxic to both pets and humans. To effectively manage this weed, removal by hand in the spring before it blooms and spreads is crucial. If the infestation has already gotten out of control, using a glyphosate-based herbicide may be necessary. However, be aware that these products can also harm grass, so reseeding will be required afterward.
Yellow Lantana
The yellow lantana’s striking hydrangea-like blooms create a captivating visual display, but its classification as a weed is what sets it apart. The plant’s broad leaves exhibit a coarse texture and an oval shape with slightly toothed edges. Its bushy appearance allows the yellow lantana to grow up to 6 feet tall and 10 feet wide, making it a notable presence in any garden or landscape.
Notably, this plant can self-seed, but due to its ornamental nature, propagation primarily occurs through cuttings, significantly reducing the risk of harm to surrounding flora. As such, the yellow lantana poses little threat to your garden’s ecosystem. While it may consume a considerable amount of space, there is no compelling reason to eradicate it entirely.
However, to maintain a harmonious coexistence with other plants, consider placing a border between the yellow lantana and your lawn or relocating the plant at least 10 feet away from your lawn.
Yellow Sorrel (Oxalis)
While yellow sorrel may be listed among weeds with blue flowers, its true hue is a sky-like shade. The plant’s distinguishing features include green shamrock-shaped leaves and inverted-heart flowers that won’t overwhelm your lawn or garden due to its relatively short stature of 3-8 inches. This weed propagates through rhizomes and seeds, rapidly spreading across your turf. Although it’s not considered invasive, yellow sorrel can still quickly colonize your landscape.
One effective means of controlling the spread is maintaining a healthy lawn that will ultimately suffocate the young plants. Alternatively, if you spot heart-shaped flowers in your grass, you can manually remove the yellow sorrel before it blooms, ensuring all roots are extracted to prevent regrowth.
Yellow Toadflax
The yellow toadflax boasts an intriguing appearance, with its creamy-yellow flowers resembling snapdragons but bearing a closer resemblance to bottle brushes. The plant’s silvery-green foliage, comprised of pointy, lanceolate leaves that grow in pairs on stalks, provides a distinguishing feature. Reaching heights of 1-3 feet, the yellow toadflax is not easily overlooked.
As with many invasive species, the yellow toadflax propagates through seeds and rhizomes, resulting in patches of growth that can disrupt the texture and form of your lawn. Furthermore, the plant has been deemed poisonous in western states such as New Mexico and Colorado, and its invasive nature only adds to its concerning properties.
To effectively combat this unwanted presence, it is recommended to utilize products containing chlorsulfuron or picloram once a few yellow toadflax plants begin flowering in your lawn. For optimal results, consider combining these active ingredients with diflufenzopyr.
Final Remarks
While we’ve already explored an extensive array of weeds featuring tiny yellow flowers that might threaten to take over your lawn, it’s essential to recognize that some of these unwanted visitors can be quite charming. In fact, they may even thrive in a carefully curated rock garden or similar setting, where their unique beauty can be fully appreciated.
However, when they start to encroach upon your meticulously maintained all-green lawn or yard, it’s crucial to take action and develop effective strategies for identifying and removing these invasive species. Our hope is that the tips and insights we’ve shared thus far will prove helpful in this endeavor, and we look forward to continuing our exploration of the world of weeds with you in our next installment.
