Did you find a new flower in your yard but aren't sure what it is? Find out if it's a flowering weed with this guide! Common yellow woodsorrel is a low-growing weed found throughout most of the US and almost all of Wisconsin. It can be a problem in gardens and lawns. Learn more about this species in this article… If you’ve made it outside on a recent sunny day, you’ve probably noticed the abundance of flowers blooming in gardens, parks, forests, and throughout King County right now. Unfortunately, the noxious weeds are out there, too—many of them bolting, flowering, and even going to seed already. Below are some of the top regulated noxious weeds…
Weeds With Flowers: 41 Flowering Weeds With Pictures
Did you find a weed with flowers in your yard, but aren’t quite sure what it is? It’s important to understand about weeds and if that type is harmful or beneficial to your garden goals. In this article, we examine the most common weeds with flowers to help you identify what stays and what needs to be relocated.
By Jason White Last updated: March 23, 2022 | 26 min read
If you’re here, you likely have an unwanted case of weeds with flowers on your hands, or you’re curious about the beautiful weed-like flower growing harmlessly in your backyard. In either case, a weed is really just a native plant that’s growing where you don’t want it to. Flowering weeds can attract pollinators, and can even be beneficial to your garden.
It’s important to note, we are pollinator friendly here at this site! We don’t advocate you removing weeds with herbicides. But there are circumstances where certain weeds may be dangerous to touch or can cause harm to your gardening goals. So in these circumstances, we recommend relocation, while understanding this isn’t always possible.
In this guide, we identify the many different types of flowering weeds you are likely to encounter in your yard, with pictures to help you identify each of them. Let’s take a look at the most common flowering weeds that may pop up so you can decide which ones are harmless and can stay, and which ones should go.
Scientific name: Convolvulus arvensis
Bindweed resembles morning glories, with 2-inch trumpet-shaped flowers in white and pink varieties. Sometimes, the flowers come with pink and white stripes. Its flowers bloom in the mid-summer and tend to remain until the fall.
But before its flowers appear, you’ll first notice bindweed vines growing over open land or up any object they come across. They have arrow-shaped leaves and latch tightly to their hosts by wrapping their thin vines tightly around them.
Should you want to intentionally plant bindweed, find dried-out pods on a plant in the wild. Then, crack the pod open and plant the seeds it contains in the fall.
Bindweed grows best in hedges and the outskirts of woods that receive full sun. It has a USDA hardiness of 4 – 8, with this perennial climber growing over six feet in ideal conditions.
Scientific name: Medicago lupulina
You may mistake black medic as a clover at first, given the heart-shaped nature of its leaves, which grow in groups of three. However, the most notable difference is that black medic is a weed that has yellow flowers instead of white ones.
During the summer, a stem emerges erect from each group of leaves, and small yellow flowers appear that collectively look like pom-poms.
Black medic thrives in tightly compacted soil, such as walkways through your garden and roadsides. It also doesn’t need much organic material, so its presence in your garden is a sign that your soil may need amending.
The plant prefers full or partial sun and neutral or acidic soil. It can handle conditions from coastlines to mountainsides. Black medic can grow in many climates within USDA zones 3a – 9a.
Scientific name: Solanum nigrum
The words “black nightshade” might give you the shivers because it contains the toxin solanine. It’s not safe for consumption for humans, or pets. Black nightshades make this list of weeds with flowers because of their white flowers that bloom starting in late spring.
They continue producing flowers until September and grow about two feet high and one foot wide. As a hermaphrodite, each plant contains male and female organs. Therefore, they rely on insects to pollinate their flowers.
Black nightshades have a high tolerance for less-than-ideal growing conditions. They do well in sandy, loamy, and clay soil. That said, wherever they grow needs good drainage and lots of sunlight. Black nightshades grow in USDA zones 10a – 11.
Scientific name: Cirsium arvense
Canada thistle is a weed that extends outside of the great white north. It has an extensive root system that makes it challenging for the average person to prevent the plant from regrowing. This weed’s purple flowers emerge from this plant in the late spring or early summer.
The flowers have a sweet smell, encouraging insects to pollinate the 1,000 – 1,500 seeds it has on each flowering shoot. Canada thistle seeds have impressive hardiness, withstanding water transportation and surviving up to 22 years underground before germinating.
The Canada thistle needs abundant sunlight and cool, well-aerated soil to thrive. It also needs lots of rain—you’ll find it in areas that receive 17 – 35 inches of annual precipitation.
Under these conditions, a single Canada thistle plant can colonize up to six diameters of space within two years. It grows in USDA zones 3a – 10b.
Scientific name: Hypochaeris radicata
Cat’s ear is known for its brilliant yellow flowers that contain several layers of petals, resembling a flatter version of a dandelion. The flowers grow from thin, wiry stems and emerge from May to September. They have tiny hairs on their leaves, and you can even eat those leaves in salad.
Once you see cat’s ear pop up in your lawn or garden, you can expect these perennials to sow their seeds well so that they return every year. They tend to grow best where there’s grass, making it even more important for you to weed your garden regularly if you don’t want them there.
Cat’s ear prefers wet environments and holds up relatively well in soil with salt. Therefore, you may find them growing around swamps and salt lakes.
The self-sowing cat’s ear thrives in USDA zones 3a – 11.
Scientific name: Stellaria media
Chickweed is an annual flowering weed. It grows tiny white flowers in the early to mid-spring. The flower petals have a small, natural split on the tip of each end. The flowers only grow to about one centimeter in diameter.
If you look closely, you’ll notice yellow, green, or red anthers emerging from its green ovary. Like its stems, chickweed’s flower stalks have a fine layer of hair. Chickweed grows best in moist soil and partial shade. If you’re not trying to grow this weed, you’ll likely find it popping up under your bushes or tall vegetation.
It isn’t picky about the soil it grows in as long as it stays moist while simultaneously having decent drainage. Chickweed grows in USDA zones 4 – 11.
Scientific name: Chicorium intybus
Chicory is an erect, straggly weed that takes over many roadsides in the summer with its pretty periwinkle-colored flowers. The flowers remain until the first frost. They grow about 1.5 inches in diameter and cluster in groups of one two five along a turdy branch.
The short-lived chicory flowers only bloom for a day. Furthermore, if they’re in a cooler climate, the flower will stay open all day. But in hot climates, they’ll only emerge in the morning.
Interestingly, it’s challenging to find chicory in natural landscapes that humans haven’t touched. Instead, it prefers the disturbed land of roads, wastelands, and pastures.
Chicory prefers temperatures between 45 – 75 degrees Fahrenheit. It likes well-drained soil, but the ground itself doesn’t need to be of outstanding quality. Chicory grows in USDA zones 3 – 9.
Scientific name: Stellaria media
The cold-loving common chickweed is one of the many weeds with flowers on this list that you can eat. They contain small white flowers with lobed petals, although some may not have any petals. The center of the flowers usually contains three each of stamens and styles, typically yellow or orange in color.
In cold climates, the chickweed is an annual plant. But in warmer areas, it becomes a perennial evergreen. Its thin stems can grow up to 16 inches, although they’re flimsy and break easily.
Chickweed has small, sporadic hairs on its stems. It has oval leaves that cascade opposite one another down the stalk.
Chickweed thrives in moist soil with full sun or partial shade. It’ll still flower in less-than-ideal conditions, but it’ll do so at a shorter height. Chickweed grows in USDA zones 4 – 11.
Common Evening Primrose
Scientific name: Oenothera biennis
The common evening primrose causes much debate over whether it’s a weed, for it has gorgeous yellow flowers that produce a lemony aroma. That said, the flowers open in the evening and close by mid-day, so you’ll have to be a night owl to enjoy them for longer.
Each common evening primrose flower contains four petals and is two inches in diameter. The plant is massive, growing up to six feet high with long, thin leaves growing from a basal rosette.
Contrary to many weeds, the common evening primrose takes two years to finish its life cycle, as it doesn’t flower until its second year. The evening primrose prefers to grow in rocky and sandy soil. It can handle any amount of sun or shade, but it prefers an average amount of rain with dry soil moisture. It grows in USDA zones 4 – 9.
Scientific name: Jacobaea vulgaris, syn
Brilliant yellow flowers are iconic of the common ragwort. They flower for the entire summer and more, starting in mid-June and dropping their petals in November. In order to bloom, this plant must have undergone cold weather exposure.
Furthermore, the common ragwort must reach a large enough size to produce flowers, which can sometimes take them over three years. Each flower produces approximately 70 seeds per head, with one plant able to release around 150,000 seeds.
Common ragworts thrive in sandy soil, as sand dunes are their natural habitat. However, you can also find this weed in grasslands and soil with few nutrients—the worse the soil for planting, the happier the common ragwort since it’ll have less competition.
You’ll find common ragwort growing in USDA zones 4 – 8, and they don’t have specific pH requirements to thrive.
Scientific name: Prunella vulgaris
It’s “common” to encounter the common self-heal plant intertwined with grass. During the months of June to September, it produces brilliant violet, pink, or white flowers. These flowers grow erect, with petals emerging from a single center.
Starting in August, common self-heal’s seeds start ripening. They have a high chance of survival, given that they grow well in sandy, loamy, and clay soils with mild acidy to mild alkalinity.
Common self-heal is among the problematic weeds with flowers to combat in gardens because it needs space to sprawl where it’ll have access to full sun or partial shade—in other words, the footpaths through your garden.
It likes soil that remains moist but drains well and avoids the shade of taller plants. Common self-heal grows in USDA zones 3 – 7.
Common St. John’s Wort
Scientific name: Hypericum perforatum
The European native common St. John’s wort is a household recognized name because of its anti-depression property. It contains deep yellow flowers with dozens of stamen that emerge around a lighter yellow center.
For ideal flower production, common St. John’s wort requires a balance between shade and sun. If the sun hits its leaves too long, leaf scorch will set in; too little sun, and it’ll reduce its flower output.
St. John’s wort will grow in practically any soil condition, from rocky to loam. As for pH, it can handle acidic to moderately alkaline earth. If you live in an area with occasional flooding, you’ll likely see Common St. John’s wort around, as it holds up well. Common St. John’s wort thrives in USDA zones 5 – 10.
Scientific name: Ranunculus repens
Glossy, yellow petals are iconic of the creeping buttercup. Its flowers often have five, although sometimes ten, petals. They emerge from thin stalks, with a single flower on the top of each of these petioles.
Creeping buttercups bloom from March to August. Although they can be an attractive plant to cover ditches on countryside roads, it has a rapid growth rate. A single plant can cover more than a 40 square foot space in one year.
Creeping buttercups love wet areas. Well-irrigated lawns, fields, and swampy areas are some of the common areas where you’ll encounter this plant. To make things worse, it’s toxic to animals that consume it.
One of the iconic features of the creeping buttercup is its ability to live in viable soil. It can remain in acidic or water-saturated conditions for 80 years before germinating. Creeping buttercups grow in USDA zones 3 – 8.
Scientific name: Veronica filiformis
Creeping speedwell is a weed that some people use as an aesthetic groundcover, given the bluish-purple and white flowers that it produces from April to July. It grows especially well between rocks, so this can be a problem plant if you’re trying to keep a clean look.
The creeping speedwell only grows 2 – 3 inches high, but a single plant can spread up to 29 inches. Its leaves vary in color from light green to gray-green, depending on the amount of sun it receives.
Creeping speedwells prefer sandy or loamy soils with a neutral pH and plenty of water. They’re fast-growing, bouncing back quickly after medium foot traffic.
Creeping speedwells grow in USDA zones 4 – 8, with tolerance for zone 9 if it has access to some shade.
Scientific name: Bellis perennis
If you have the daisy weed pictured as having bright white petals and a yellow pom-pom center, you’re spot on. While these flowers are attractive in areas where you want them, daisies are weeds with flowers that spread wildly.
Their flowers range from 1 – 1.5 inches in diameter, and they have broad leaves up to 2.5 inches long. The tops of daisy weed leaves have a series of small, harmless spikes.
Garden walls, cracks in paving, and rock crevices are some of the many places where you’ll encounter wild daisy weeds. They grow well in compacted soil where other plants can’t thrive. Even in more fertile soil, daisy weeds create a thick mat, suffocating other plants.
Daisy weeds spread extra quickly in their preferred growing conditions of moist soil and full sun. They grow in USDA zones 4 – 8.
Scientific name: Taraxacum
Dandelions are perhaps the most classic example of weeds with flowers on this list. They contain a flower head of bright yellow ray flowers. The outer bracts point down, with the remaining petals facing up.
The dandelion produces flowers from March to September. Then, as fall approaches, its petals drop to reveal spherical seeds that the wind carries.
Perhaps to the surprise of the average gardener, dandelions have many uses, including eating the baby leaves in salads and using the white liquid in their stalks as glue.
Dandelions prefer growing in disturbed (cultivated) ground with access to lots of sunlight. They grow up to 28 inches tall in soils with a pH between 3 – 9 and when they’re out of the path of lawn mowers. Dandelions grow in USDA zones 3 – 9.
Scientific name: Commelina communis
The dayflower is a weed that produces an intricate periwinkle-colored flower that ranges from .5 – 1-inch wide. It only has three petals—two larger periwinkle ones and one small white one. But it doesn’t end there. The dayflower has three long white sepals and five or six yellow stamens that make it look like an exotic tropical plant.
These flowers stay in blossom for about one to two months during the mid-summer to early fall. When the dayflower isn’t in bloom, it has glossy deep green leaves that have a slightly upward curl.
Despite its beauty, the dayflower is an aggressive grower, which is why people consider it a weed. It likes loamy or somewhat sandy soil and full or partial sun.
Daylilies need moist or semi-most water to thrive. They grow in USDA zones 5b – 8a.
Scientific name: Erigeron sp.
Some people call fleabanes the eastern daisy fleabane, given that it looks like a miniature version of a daisy. It has an outer layer of white florets and smaller inner disc florets attached to a yellow center. The flowers emerge in the summer, and they may have an additional bloom in the fall.
The fleabane’s stem usually contains several stalks with a single flower attached to each branch. These stalks have tiny, soft hairs.
Fleabanes grow fibrous roots which can turn into a taproot if you give them enough time. It loves open, sunny areas. However, it usually finds the least amount of competition in poor-quality soil. You’ll encounter fleabanes in soil ranging from acidic to alkaline. They grow in USDA zones 5 – 9.
Scientific name: Lamium purpureum
Giant hogweed has a similar appearance to Queen Anne’s lace (which we’ll cover further down), except it grows up to 15 feet tall compared to four feet. It contains a mass of tiny white flowers that form a single, slightly upward-turned flower look.
The giant hogweed produces flowers in June and July, with each flower mass reaching up to 60 centimeters in diameter. In the fall, the flower gives way to flat but oval-shaped seeds.
Although giant hogweed can turn heads, avoid touching it with your bare skin. Its sap can cause burns, scarring, and even blindness if you get it in your eyes.
Giant hogweed can grow in just about any space, from ravines to creekbanks to woods. They take up residence in nearly any soil type they can dig their roots into. Giant hogeweed grows in USDA zones 3a to 9b.
Scientific name: Solidago sp.
The thought of goldenrods might have you sneezing, but when you have it under control, this weed with fluffy yellow flowers allures bees and butterflies to gardens to pollinate your crops.
A goldenrod’s flowers bloom in the late summer and fall. It has long branches where tiny yellow flowers form with tips of deep orange. Despite their attractive appearance, goldenrods are weeds because of their invasive nature and because they usually don’t have flowers for most of the year.
Goldenrods will take up home in just about any area they can. They don’t have a strong preference for soil type, and they’ll happily lap up water while also being able to handle prolonged droughts.
Perhaps unfortunate for your garden, it’s uncommon for pests or diseases to wipe out a group of goldenrods. They grow in USDA zones 3 – 9.
Scientific name: Senecio vulgaris
Groundsels have small yellow flowers that stay open for much of the year. As they prepare to seed, they drop their petals and turn fluffy and white, much like a dandelion.
Although the groundsel’s flowers look like single entities from afar, up close, you’ll notice they have a composite head, with many small flowers clustered together.
The groundsel grows up to 18 inches tall with alternating leaves that have coarse but harmless teeth, diving the foliage into lobes. A taproot that grows close to the surface holds it in place with the support of secondary fibrous roots.
It’s common to spot groundsel growing along roads, around landfills, and cracks in your cement. It can grow in just about any soil, although it prefers soil ground. Groundsels grow in USDA zones 3 – 9.
Scientific name: Cardamine hirsuta
Hairy bittercresses are ground weeds that show their faces in April and May when small white flowers pop up around their round green leaves. They belong to the mustard family, and as such, they set out on a fast-growing spree once their seeds germinate.
While we’re on the topic of seeds, the hair bittercress’ flowers change into long seedpods as they near the end of their life cycle. These seedpods then burst when they become dry, using wind to disperse them.
Hairy bittercress enjoys cool and moist soil, making this a weed you’ll likely have to battle in the spring. A deep taproot makes it challenging to uproot this plant permanently.
You may find hairy bittercress growing under and around your garden plants in USDA zones 4 – 8.
Scientific name: Lamium amplexicaule
The henbit is both a weed and an herb, as you can use its flowers, stem, and leaves in tea. Although it belongs to the mint family, this plant tastes closer to kale.
Henbits produce small deep pink elongated flowers in the upper circular parts of their leaf axils. They have an orchid-like appearance, showcasing a white face and red flecks. Nevertheless, this plant is a weed because it spreads quickly, helped by its ability to grow roots from its stems that touch the ground.
Wrinkle-like leaves are a characteristic of henbits because of their recessed upper veins. The plant has a thick stem but doesn’t grow higher than 30 centimeters.
The henbit’s favorite soil is well-tilled and dry. It, therefore, enjoys growing in fields and gardens, but you can also find it in waste areas. Henbits grow in USDA zones 4 – 8.
Scientific name: Geum urbanum
The herb bennet grows small yellow flowers between the months of May and August. The 5-petal flowers droop shortly after emerging. What follows are spiny seed heads. They have red hooks on their ends, making them cling to passing animals and humans.
Needless to say, herb bennets are one of the weeds with flowers that you really don’t want growing nearby. However, some people use herb bennet leaves and roots as a spice for soup.
These weeds love shady areas, as they often live in woods, hedgebanks, and under scrub. They also require nutrient-rich soil to thrive and a decent amount of water in a well-draining area. Herb bennets are self-fertile and like just about any range of soil pH. These plants live in USDA zones 5 – 9.
Scientific name: Geranium robertianum
Herb Robert produces bright pink flowers in wooded areas during the spring and summer. Its leaves and stems are naturally green. But if this plant has too much access to the sun, it turns red and develops dark spots.
As its name implies, Herb Robert is more than a weed; it’s an herb that people use as an antiseptic and insect repellent. Although funguses can sometimes plague this plant, overall, it’s a hardy species that can outlive many other plants around it.
Herb Roberts grow as tall as 20 inches when they’re in moist and darkly lit conditions. They often sprout between cracks in rocks and produce small red fruits.
These herbs thrive in nitrogen-rich soil but die if they’re in a wet area for too long. Herb Robert grows in USDA zones 5 – 9.
Scientific name: Datura stramonium
Jimsonweed is in the nightshade family with a fragrant trumpet-shaped flower on each of its forked branches. The colors of its petals range from white to cream to violet. Perhaps unsurprisingly for those familiar with nightshades, this weed’s flowers open at night.
You can find Jimsonweed growing along roads and in feces-ridden pastures in just about any part of the world with a warm climate. It also goes well growing around landfills.
Jimsonweed contains poisonous properties, although people consume it for its psychoactive properties. It has the greatest amount of toxin before flowering; after that time, it becomes relatively safer.
Sunny and partly shaded areas are ideal for Jimsonweed. It can grow in most soil types, including calcareous and clay loam, but it prefers earth that remains dry. Jimsonweed grows in USDA zones 6 – 9.
Scientific name: Ficaria verna
Lesser Celandine is in the buttercup family. So, it has glossy yellow petals and a star-shaped design. Each flower contains 8 – 12 petals. Its leaves also have a shiny appearance with a heart-like shape that sits on long stalks.
The low-growing lesser celandine flowers from January to April, but its leafy greens appear in the fall and winter. You can find it in gardens, woodlands, and grasslands. Damp areas are paramount to this weed. So, it also congregates along stream banks and ditches.
Unlike many weeds, lesser celandine has specific growing requirements. It doesn’t do well in dry areas, requires shade, and needs basic to alkaline soil.
Lesser celandine is a fast-growing plant, thanks to its underground runners and tubers. Therefore, it’s quick to invade garden edges and the shaded areas your plants provide. Lesser celandine grows in USDA zones 4 – 8.
Scientific name: Erigeron canadensis
Marestail, or horseweed, is an annual weed that grows in an erect fashion. It gets its name because it has a single central stem where leaves grow out of, forming a bushy “tail” of up to seven feet high.
Several flowers emerge on the branches at the top of this plant during the late spring. Its small, white flowers house thousands of minuscule seeds that’ll disperse through wind and the end of the season.
Although many horseweed plants die after dispersing their seeds, over half manage to survive the winter. Seeds usually sprout quickly versus having dozens of years of longevity like some other weeds.
Marestail loves coarse and well-draining soil. Preferably, the soil should be loamy or with high organic content. Although it appreciates a decent amount of water, it can withstand drought. Marestail flourishes in USDA zones 3 – 11.
Meadow Death Camas
Scientific name: Zygadenus venenosus
Meadow death camas are among the poisonous weeds with flowers that we’re covering here. They have attractive white flowers with yellow centers, with multiple small flowers forming a triangular-shaped head at the top of its stalks.
The meadow death camas have long stamens that add to their delicate design. They bloom from April to July and have grass-like leaves that grow in an upward v-shape from the ground. So, when they’re not in bloom, it’s easy to mistake them for high-growing grass.
You’ll find meadow death camas growing in mostly dry climates. They do well on hillsides, sagebrush slopes, and in meadows that receive little rain.
Because of its toxins, the mining bee is the only known insect that can pollinate the meadow death camas. It grows in USDA zones 8a – 11a.
Scientific name: Asclepias sp.
Any child who grew up in the countryside where milkweed grows knows that this weed releases a sticky white milk-like liquid when you snap its stem. It’s an extremely fragrant plant, attracting insects of all kinds for feasting and pollination.
Milkweed produces flowers in several colors, including pink, purple, green, and orange. Many tiny flowers cluster together at the top of its 2 – 5-foot stalk, creating a ball-shaped appearance.
Its large, green leaves make it a favorite spot for monarch butterflies to lay their eggs beneath. When the larvae hatch, they feed on the plant’s foliage.
Milkweed loves lots of sunlight and can hold up well in most soil conditions. That said, there are some species, such as swamp milkweed, that need damp, fertile earth to survive. Milkweed grows in USDA zones 3 – 9.
Scientific name: Urtica dioica
You may not look at the nettle and see flowers right away, but this perennial flowering plant contains many small green to brown-colored flowers. The flowers remain in bunches along the length of its stem.
The nettle’s leaves contain lots of small hairs. Although this particular species isn’t poisonous, some species contain toxins in their hairs that can create painful stings if they break off onto your skin. In either case, having a run-in with nettles can be painful.
Nettles require soil with high nitrogen levels. They prefer partial shade and well-aerated soil with a pH ranging from 5.0 – 8.0.
It’s common to encounter nettle on the edges of fields and along pastures, where it can cause issues for livestock. Nettle grows in USDA zones 3 – 10.
Scientific name: Corniculata
The oxalis is a weed with attractive 5-petal flowers. The colors vary from white to pink to red and yellow. Regardless of the base color, oxalises have many stripes running from their center to the tips of their petals.
It contains 3 – 10+ leaflets resembling clover leaves that attach to a woody stem. Oxalises are sensitive to light, so they may adjust their leaf angle to avoid excessive amounts of sunlight.
The leaf color of Oxalises can vary from deep shamrock green to maroon. As such, some people use this weed for decorative purposes, although potting it is best given its fast-spreading nature.
Oxalises prefer partial shade and well-draining, organic soil. If they get too hot during the summer, they’ll drop their leaves. These weeds grow best in USDA zones 7 – 10.
Scientific name: Phytolacca americana
Pokeweed is a plant that has some medicinal properties, but its main draw is its red berry that people use to make ink and red food coloring. Nevertheless, it’s not a plant you likely want around your property—it can grow up to ten feet high.
The flowers of pokeweed look different from average. They have pink-colored racemes with usually white to green flowers via their five sepals, although they don’t have true petals. The flowers then turn into purplish-black berries that form this iconic-looking plant.
Pokeweed prefers sunny areas, so it grows in fields and around forest edges. The flowers occur from May to October in cooler climates and year-round in warmer areas.
Unfortunately for those with acidic soil, pokeweed will happily grow in soil with a pH as low as 4.7. It grows in zones 4 – 8, including neutral to slightly alkaline soils.
Queen Anne’s Lace
Scientific name: Daucus carota
Queen Anne’s lace is a weed with flowers that live up to their name; they have tightly grouped white flowers that come together with small spaces of air between them, resembling lace. If you leave Queen Anne’s lace untouched, they’ll produce these flowers starting in their second year.
Furthermore, Queen Anne’s lace is tall, waving its flat-topped flowers up to four feet in the air. Its leaves also have a pleasant appearance for a weed, as they have the long, narrow leafy appearance of ferns.
When seeded in open areas, Queen Anne’s lace spreads wildly. It enjoys growing in fields and other sunlit spaces.
Although this weed will grow in practically any soil, it prefers well-draining soil with neutral or alkaline soil. Queen Anne’s lace grows in USDA zones 3 – 9.
Scientific name: Galinsoga parviflora
You can’t tell that quickweed is part of the sunflower family by looking at its flower, but that’s exactly what it is. It contains a small, round yellow center with five tiny white petals surrounding it. Each petal has space between it, and they seem disproportionately small compared to this weed’s center.
Quickweed appears in gardens early in the summer and has a shallow root system. So, they’re easy to weed. However, they’re excellent seed spreaders, so it’s challenging to combat quickweed once it’s there.
You can eat quickweed’s fuzzy leaves with salad, and some people also use it for medicinal purposes—most notably, nettle stings.
Quickweed enjoys partial sunlight and northward-facing slopes. They prefer moderately dry areas with 400 – 800 mm of annual rain. Quickweed grows best in USDA zone 9.
Scientific name: Chamaenerion angustifolium
The rosebay willowherb won’t strike you as resembling a willow, but it does have a tall, wispy nature, with its grassy leaves growing up to 1.5 meters. It produces alluring pinkish-purple flowers from June to September.
Rosebay willowherbs are a weed because of their ability to quickly take over open spaces, rapidly growing tightly together so that they block out other plant competition. You can find them at the edges of forests, grasslands, and wasteland.
To grow their leaves that spiral upwards around their stem, the rosebay willowherb needs a combination of sun and shade with dry or moist soil.
Rosebay willowherbs aren’t picky about soil type; you can find them in sandy, loamy, and clay soils. They also grow well in various soil pH, from mildly acidic to slightly alkaline. They grow in USDA zones 3 – 7.
Scientific name: Convolvulus cneorum
Field bindweed has attractive trumpet-shaped white flowers that begin with pink buds. These weeds with flowers bloom from the spring to the summer. Field bindweeds love hot and dry summers, as they’re native to the Mediterranean. It’s also when they maximize their seed production.
Because of their intricate root system, field bindweeds have an excellent tolerance for drought. They can also manage to grow in tightly packed or tilled land.
Nevertheless, their ideal conditions are fertile soil that drains well. It’s common to see these weeds growing along the sides of roads and in pastures.
Field bindweed is an evergreen shrub that grows up to more than three feet high. It thrives in USDA zones 8a – 10b.
Scientific name: Polygonum sp.
Smartweed is an attractive weed if you don’t mind where it’s growing, for it has a series of pinkish-white flowers that sit tightly on top of each other, following the topmost 1.5-inch part of its stalk. Instead of petals, these flowers have sepals that give them a petal appearance.
You can expect the smartweed you encounter to grow upwards of six feet tall, although the flowers and leaves might start bending under their own weight as they grow. They differ from knotweeds, which have a similar appearance but with flowers clustered around their leaf axils.
The smartweed produces flowers from June to November. Often, the outer side of the sepal is a deeper pink, and the inner side is whiter once it opens.
Smartweed loves growing in wet areas, including along streambeds, wetlands, and ditches. They prefer rich soil and grow in USDA zones 3a – 10b.
Scientific name: Trifolium repens
Wild clovers are an iconic weed that flowers with its pom-pom purplish-white flower emerging on single stalks in grassy areas. It grows up to 40 centimeters tall, and you can spot its flower from May to October.
Although most weeds on this list aren’t something you want around your garden, the wild clover may change your mind. It contains a high amount of nitrogen, improving local soil quality where it grows.
It’s common to spot wild clovers in drought-prone areas, as they don’t need much water to survive. Furthermore, they hold up well in both full sun or partial shade, so they’ll sometimes overtake other weeds.
Wild clovers can grow in practically any soil type, and they hold up well even during trampling, to the dismay of a gardener. It grows in USDA zones 3 – 10.
Wild Multiflora Roses
The multiflora rose is a wild rose, and considered invasive due to being imported and spreading unchecked.
Scientific name: Rosa sp.
Wild roses may not seem appropriate in an article about weeds with flowers, but these roses don’t have the beautiful silky cups that you’d give your partner. Instead, they have five petals that splay out in an almost flat shape.
As a result, you can see this flower’s yellowish-white center. Wild rose petals vary in color, but most have a pink and white mixture. They also have spines on their thick, woody stalks, just like modern-day (grafted) roses. These plants are imports from overseas and are considered quite invasive.
Wild rose bushes grow in sunny areas with well-draining soil, although there’s a variety of this species called the swap rose that does well in wet conditions. When they grow too closely together, diseases can set in since airflow is crucial to keeping them healthy.
Of course, you may not want these plants to stick around, given that their woody bases can be tough to remove. Wild roses grow in USDA zones 3 – 8.
Wild violets are usually not offensive, despite being considered a weed. They are commonly used for groundcover.
Scientific name: Viola odorata
Like wild roses, wild violets are the original, non-grafted version of the violet most people grow in their gardens. They’re a fast-growing plant that quickly spreads its seeds, making wild violets a weed in many gardeners’ and homeowners’ eyes.
Most wild violets have purple flowers with a white, hairy interior. However, some of these flowers may have yellow or white exteriors.
Wild violets flourish in woody areas and along stream banks. They like rich organic soil and moisture without being in standing water. If wild violets grow in an area with a lot of sunlight, they’ll drop their flowers to survive. These weeds grow in USDA zones 3 – 9.
What’s a weed to one person may be another’s treasure. After all, someone had the foresight to turn wild roses and violets into the refined flowers we enjoy in our gardens today.
The ball is in your court now that you know how to identify common weeds with flowers. If you have a poisonous weed growing on your property, removing it is a no-brainer. But if you enjoy the flowers on harmless weeds in your backyard, you just might want to start calling them a “plant” instead of a “weed.”
Common Yellow Woodsorrel, Oxalis stricta
Common yellow woodsorrel.
Common yellow woodsorrel, Oxalis stricta, is a native North American plant (also found in Eurasia) which is usually considered a weed. It has numerous common names, including common yellow oxalis, sour grass, shamrock, sleeping beauty, sour trefoil, and sheep’s clover. It also has many synonyms: Ceratoxalis coloradensis, O. dillenii, O. europaea, O. prostrate, O. rupestris, and Xanthoxalis florida. It is found in 46 states but is most numerous in the eastern U. S. and into Canada. This species differs from other wood sorrels by being more erect, the stems grow at a sharp angle (about 90º) from the main stem and the seed pods bend sharply upward on their stalks.
An infestation of common yellow woodsorrel.
Common yellow woodsorrel is distinct from other wood sorrels in that the seed pods bend sharply upward on their stalks and the stalks also grow at a sharp angle from the main stalk (both angles are about 90 degrees). It also tends to grow in a more upright fashion than other wood sorrels (stricta means “upright”).
This herbaceous plant may grow either as an annual or as a weak perennial. Although it prefers moist soil, and partial shade, it is tolerant of a wide range of conditions. It is commonly found in fields, woods and borders, along roadsides and in other waste areas, and will even grow in the cracks of sidewalks.
Common yellow woodsorrel in a lawn.
It is also a common summer annual in lawns. As one of the latest germinating annual weeds, it often fills in spots left in the turf after broadleaf weeds are killed by early spring herbicide applications.
The delicate-looking plants grow 6-15″ tall – unless they are mowed off consistently in a lawn. They may form colonies arising from slender but tough underground stems (rhizomes), but more often are individual, seed-grown plants. The weak stems branch at the base and sometimes will root at nodes.
The trifolate leaves have heart-shaped leaflets.
Leaves are alternate, smooth and palmately compound. Each leaf is divided into three heart-shaped leaflets similar to a clover leaf, with faintly hairy margins. The leaves are creased and fold upward in half at night or when stressed (such as if picked or during storms). Most plants are green but some have a purple cast.
Common yellow woodsorrel has yellow flowers with five petals, which are followed by erect seed pods.
The yellow flowers have 5 petals that are held in an open cup up to ½” across on a long stalk. They occur singly or in axillary clusters of up to five flowers. Blooms first appear in mid spring and continue through fall. The flowers are followed by elongated, ridged seed pods that are pointed at the end. The erect seedpods are held at right angles with their stems. Each ½-1” long capsule has five compartments with about 10 seeds in each compartment. When the pods are ripe, they dehisce (open explosively at the slightest touch), launching the seed as far as 8-10 feet.
A common yellow woodsorrel seedling.
The leaves, flowers and unripe fruits are edible, with a sour, tart, lemony flavor. They can be added to salads, soups, or sauces, or used as a seasoning. However, it should be consumed in moderation because the plant contains rather high levels of oxalic acid which is toxic in excessive amounts. It should be avoided by those with kidney disease, kidney stones, rheumatoid arthritis, or gout.
Common yellow woodsorrel is best controlled by hand weeding and mulching. It pulls up quite easily and does not resprout from roots left behind. Try to remove plants before seed pods develop – although this may be difficult as it is good at hiding among other plants, producing seeds before it is ever noticed. Most herbicides are not very effective on Oxalis species. Pre-emergence herbicides, which prevent germination, are the most useful.
– Susan Mahr, University of Wisconsin – Madison
Noxious weeds to watch for in June
If you’ve made it outside on a recent sunny day, you’ve probably noticed the abundance of flowers blooming in gardens, parks, forests, and throughout King County right now. Unfortunately, the noxious weeds are out there, too—many of them bolting, flowering, and even going to seed already.
Below are some of the top regulated noxious weeds to keep an eye out for this month. Please let us know if you see one of these high-priority invasive plants, so we can make sure they’re controlled or eradicated in time! [Click here to go to the King County Noxious Weed List for the whole list!] Report locations and share photos with us easily on our new and improved Report a Weed online form.
1. Top priority: eradicate before seeds disperse
First up, weeds already going to seed or getting close. Catch them now before seeds disperse!
Many garlic mustard plants in King County are going to seed. Note the long, skinny seed pods on this one.
Garlic mustard (Alliaria petiolata), a Class A noxious weed, is a biennial or winter annual herb, can self-pollinate to produce 62,000 seeds and overtake a relatively undisturbed forest understory. Eradicating it before seeds mature is key. You can identify garlic mustard by:
- Scallop-edged, rounded leaves (on rosettes) or toothed triangular leaves (higher up on mature plants) that feel smooth (hairless) and smell like garlic smell when crushed
- Small, 4-petaled white flowers and long, skinny seedpods
- Root bent in a distinct “s” shape
- Highly variable form, maturing and setting seed at anywhere from a few inches to 6 feet tall
Garlic mustard rosette leaves are more rounded or kidney-shaped, while mature plants have more triangular leaves. All leaves are lobed.
Many shiny geranium plants are forming seed capsules (the crane’s-bill-like shapes next to the flowers), though they aren’t dispersing their seeds quite yet.
Shiny geranium (Geranium lucidum), a Class B noxious weed, is an annual herb that grows in disturbed areas such as roadsides, as well as in shady woodlands and forest openings. This weed is already starting to form seed capsules, though it isn’t dispersing seeds yet. You can identify it by:
- Reddish, smooth stems that can reach 20 inches tall
- Shiny, round to kidney-shaped leaves with 5-7 lobes, usually shiny (not fuzzy)
- Leaves often turn red in sun or as plants are going to seed
- Tiny pink-purple 5-petaled flowers that appear in pairs at stem ends
- Keeled sepals
- Seeds in long capsules that look like cranes’ bills
- Does not smell bad like herb Robert and is not covered with soft hairs like Dove’s foot geranium
Shiny geranium can invade a variety of areas, from roadsides to woodlands. Photo by Matt Below.Photo by Matt Below.
2. In full flower
The next group of weeds are now in full flower and before long will go to seed. Make sure you eradicate them from your property before they do.
Milk thistle’s large, pink-purple flower head with broad, spiny bracts around its base is in full bloom right now. Photo by Dan Sorensen.
Milk thistle (Silybum marianum) is a Class A noxious weed that grows 2 to 6 feet tall and is a winter annual or biennial that grows mostly in rural parts of King County. You can identify it by:
- Shiny green leaves with distinct milky-white marbling
- Spines on leaf edges and stems
- Large, pink-purple flower heads appearing singly at stem ends
- Broad, fleshy, spiny bracts around base of flower head
Milk thistle’s large, pink-purple flower head with broad, spiny bracts around its base. Photo by Dan Sorensen.
A bee enjoys an orange hawkweed flower. Be sure to time your noxious weed control so that it has the least impact on pollinators and other animals that might be using the plant.
Orange hawkweed (Hieracium aurantiacum) and yellow hawkweed (Hieracium caespitosum) are two Class B perennial herbs that readily invade roadsides, pastures, grasslands, and other areas throughout King County. Both weeds spread via seeds and stolons. You can identify them by:
- Hairy, unlobed leaves in rosettes at the base of hairy, almost leafless stem
- Black, ball-shaped, tightly-clustered flower buds followed by orange (H.aurantiacum) or yellow (H. caespitosum) blooms (look like little dandelion flowers)
- Milky juice inside all plant parts
- Fluffy, dandelion-like seed heads
- Fuzzy white stolons (runners)
Dalmatian toadflax grows especially well in disturbed areas with rocky soil, such as around train tracks. Photo by Sasha Shaw.
Dalmatian toadflax (Linaria dalmatica ssp. dalmatica), a Class B noxious weed, is a perennial plant that grows to 3 feet tall and mostly grows in disturbed areas in western Washington. It spreads by both seed and spreading roots. You can distinguish it by:
- Multiple stems that grow from one woody base
- Bluish green, heart-shaped, waxy leaves that wrap around each stem
- Bright yellow, snapdragon-like flowers growing in rows at stem ends
Sulfur cinquefoil is blooming now, displaying its pale yellow flowers with 5 heart-shaped petals and darker yellow centers.
Sulfur cinquefoil (Potentilla recta) is another Class B noxious weed and perennial herb that reaches 3 feet tall. You can distinguish it by:
- Palmately lobed leaves with 5-7, long, toothed leaflets
- Upright, hairy, leafy, mostly unbranched stems (hairs stick straight out from stems unlike on the similar native species graceful cinquefoil, Potentilla gracilis)
- Pale yellow flowers with 5 heart-shaped petals and darker yellow centers
3. Budding or starting to flower
At a bit earlier stage in their life cycles, the following plants are either budding or just starting to bloom.
Tansy ragwort plants are bolting, and some are even starting to form flowers.
Tansy ragwort (Senecio jacobaea), a Class B noxious weed, is a biennial found throughout King County that is toxic to horses, cattle and other animals. It quickly takes over disturbed areas, thriving in sites with full sun and dry to somewhat wet soils. You can identify it by:
- Ragged, ruffled leaves that are dark green on top and light-green below, with deeply cut, blunt-toothed lobes
- First year plants are basal rosettes; second year plants have 2 to 4-foot-tall flowering stalks
- Clusters of numerous small daisy-like flowers with 13 yellow ray petals and yellow-orange centers
Tansy ragwort often spreads in pastures and fields where it out-competes grass. It is toxic to horses, cattle and other animals.
Giant hogweed (Heracleum mantegazzianum), a Class A noxious weeds, is a perennial that usually grows in urban areas, especially where there’s rich, damp soil. This plant is poisonous, and touching its sap can cause severe blisters or even scars, so it’s good to know how to recognize it. You can identify it by:
- 8-15-foot-tall, hollow, ridged stems with reddish-purple blotches and stiff white hairs
- 3-5-foot-wide, deeply incised, compound leaves
- Surface of leaf underside is hairless, with hairs only on ribs
- 2-foot-wide umbrella-shaped flower clusters
Spotted knapweed will soon be blooming. Its silver-gray hue is a good way to identify it even without flowers. Photo by Tricia MacLaren.
Spotted knapweed (Centaurea stoebe), a Class B noxious weed, is a biennial or short-lived perennial that often appears in disturbed areas, especially those with full sun and well-drained soils. You can identify it by:
- 5-foot-tall, upright, branched stems
- Medium-green, somewhat silver-gray, often deeply lobed leaves
- Small, oval flower heads with light purple to pinkish, thistle-like flowers
- Bracts at base of flower head have triangular black spots
- Stout taproot
Spotted knapweed’s small, oval flower head with light purple to pinkish, thistle-like flowers. Note triangular black spots on bracts at base of flower head.
Meadow knapweed is starting to bloom, revealing its oval, pink to reddish-purple flower heads. Up close, look for the comb-like fringes near bract tips around the flower head base.
Meadow knapweed (Centaurea jacea x nigra), another Class B noxious weed related to spotted knapweed, is loner-lived perennial that grows in not only disturbed sites, but also riverbanks, pastures, moist meadows, forest openings, and other areas. You can identify it by:
- 4-foot-tall, upright, branched stems
- 4-inch-long, slender, often shallowly lobed basal leaves and smaller, unlobed stem leaves, all coarse and tough
- Single oval flower heads with pink to reddish-purple flowers at branch ends
- Bracts at base of flower head have comb-like fringe near tip
Meadow knapweed’s oval flower heads with pink to reddish-purple flowers grow singly on stems. Bracts at base of flower head have comb-like fringes near their tips.
Meadow knapweed reaches 4 feet tall, with upright, branched stems. Stem leaves are unlobed and smaller than basal leaves.
4. Plants to keep an eye on
Plants in this final group are putting their energies into growing right now. They won’t go to seed until later this summer, but keep a tab on them and make sure you’re ready to control them when the time comes.
While not 8 feet tall yet, many policeman’s helmet plants are large enough to spot. Look for large, oblong or egg-shaped leaves with serrated edges, growing opposite or whorled in groups of 3 on stems.
Policeman’s helmet (Impatiens glandulifera), Class B noxious weed, is a 3 to 8-foot-tall annual that grows especially well in moist areas, such as wetlands, streams, and damp woodlands. You can identify it by:
- Upright, hollow, watery, purple-reddish tinged stems
- Large, oblong or egg-shaped leaves with serrated edges, growing opposite or whorled in groups of 3
- White to pink to purple 5-part flowers that resemble an English policeman’s helmet
- Stem base and exposed roots often reddish
Policeman’s helmet has large, oblong or egg-shaped leaves with serrated edges, opposite or whorled in groups of 3.
Purple loosestrife is bolting right now. Look for 4-6-sided stems and simple, smooth-edged leaves appearing opposite or whorled on stems.
Purple loosestrife (Lythrum salicaria), Class B noxious weed, is a deep-rooted, rhizomatous perennial found mostly in damp areas, such as freshwater and brackish wetlands, as well as lakes and streams. It spreads through both vegetative growth and seeds. You can identify it by:
- Stiff, 4-6-sided stems that reach 6-10 feet tall
- Simple, smooth-edged leaves that grow opposite or whorled on stems
- Tall spikes of small magenta flowers with 5-7 petals
- Woody taproot
Garden loosestrife is growing tall. Look for softly hairy stems and leaves along with lance- or egg-shaped leaves usually arranged in whorls of 3.
Garden loosestrife (Lysimachia vulgaris) is another Class B noxious weed and deep-rooted perennial often found in wet areas, although it’s not related to purple loosestrife (despite the common names). Garden loosestrife spreads primarily via creeping rhizomes. You can identify it by: