Weeds With Yellow Flowers: Are They in Your Yard or Garden?
Did you find a plant with yellow flowers in your garden space, but aren't sure what it is? There's actually a chance it could be a weed that's sprouted yellow flowers! In this article, we take a look at some of the most common yellow flowered weeds to help you identify these plants and replace them with other plants for local pollinators.
A weed with yellow flowers growing in the wild might provide happiness to a child, but not necessarily most gardeners. Whether you’re trying to prevent weeds from popping up in your garden or exploring the native plants of your region, learning more about weeds is a good idea. It’s important to note that many of these weeds are good for pollinators. But that doesn’t always mean that they are great for gardens, especially vegetable gardens.
While we don’t advocate eradicating weeds that are beneficial to pollinators, it may be worth your time to relocate them to a different area of your yard. Some wild plants with yellow flowers can rob your purposely planted vegies or flowers of space, water, and nutrients. Others can be a magnet for wildlife, including deer and animals that may move on to eating other garden plants.
Most gardeners would rather choose to plant flowers that they love, rather than have weeds that grow yellow flowers all over their yard or garden space. Knowing what’s considered a weed when you see yellow flowers start to bloom from the plant, can help you identify the best way to manage them.
Bird’s Foot Trefoil
Scientific name: Lotus corniculatus
This perennial legume can reach a height of three to five feet and has yellow flowers in a whorl pattern. This weed likes plenty of precipitation and moderately acidic soil. Bird’s foot trefoil can be useful in erosion control, but it can also take over, crowding out other plants with the dense mats it forms.
One way to keep from spreading bird’s foot trefoil in your yard is to clean boots and gear used when hiking in wilderness areas. Bird’s foot trefoil that does take root in your yard and gardens can be controlled by pulling them regularly once seen.
Scientific name: Rudbeckia hirta
Believe it or not, Rudbeckia is often considered a weed, depending on your location. More wildflower than weed, black-eyed susans have stems one to three feet long with orangeish yellow flowers at the ends. These flowers are also known as Rudbeckia and Cone Flowers and have clusters of tiny brownish flowers at the center of each blossom. Some varieties of rudbeckia are orange flowered weeds, depending on where they are grown.
Black-eyed susans bloom from June to August. Though these weeds will just pop up in yards and the wild, many people are happy to see them growing on their property. Black-eyed susans are so prized that they are the Maryland state flower and a symbol of the University of Southern Mississippi because of their black and gold flowers.
Scientific name: Solidago canadensis
This weed thrives in moist, sunny conditions. Canada goldenrod blooms from August to October, showing its flowers in a pyramid formation. In the wild, Canada goldenrod is an important nectar source for bees.
Canada goldenrod has medicinal properties and was used by Native Americans to make infusions and sedatives.
Since Canada goldenrod can reproduce through its root system, it can be difficult to control. Remove Canada goldenrod at the root, before the flowers go to seed to achieve the best results.
Scientific name: Senecio vulgaris
Part of the daisy family, common ragwort is an annual that can germinate in summer, spring or fall. This weed is a bane to allergy sufferers, can be toxic to herbivores in nature. Because common ragwort can be so prolific, eradicate it before its flowers go to seed. Otherwise, you will quickly have a common ragwort infestation.
Common ragwort isn’t a pest to butterflies, though. It’s one of the most popular flowering weeds among butterflies, so if you’re growing a butterfly garden, you might want to keep this weed among your other plants.
Common Evening Primrose
Scientific name: Oenothera biennis
This weed, common evening primrose, is valued as a wildflower. Common evening primrose and its trumpet-shaped flowers that open in the evening can be found in fields and woodland areas.
Used by Native American tribes as a food source and to treat pain, common evening primrose is also a source of nectar for hummingbirds.
Common evening primrose can grow to six feet in height, and while some will even buy seeds for this weed, not everyone wants Common Evening Primrose. It can be removed fairly easily by pulling at the root.
Common St. John’s-Wort
Scientific name: Hypericum perforatum
Reproducing through rhizomes, seeds, and stems, common St. John’s-wort has numerous five-petaled flowers at branch ends. These flowers bloom in July and August in the northern United States.
Introduced to North America as an ornamental and medicinal plant in the 17th century, common St. John’s-wort can crowd out native species. The plant is also toxic when eaten by livestock grazing.
Over-exposure to common St. John’s-wort can cause skin lesions, so take care and wear gloves if hand-pulling young common St. John’s-wort.
Scientific name: Ranunculus repens
Another common weed with yellow flowers is the creeping buttercup. This low-growing plant can be found in wet soil, where it sinks fibrous roots. Flowers about a half-inch in diameter have five to seven petals and clusters of stamens and pistils at the center.
A dense lawn that’s well-drained will prevent creeping buttercup from taking over. Keeping grass trimmed and fertilized will make it strong enough to stand up to this weed. It’s also fairly easy to pull when necessary.
Scientific name: Potentilla reptans
Creeping cinquefoil is among the most common weeds—popping up on lawns that have been neglected. With segmented, jagged-edged leaves, creeping cinquefoil has small flowers. Once creeping cinquefoil makes itself at home in your lawn, it spreads aggressively through its creeping stems that take root.
This weed is an invasive plant and can form a monoculture when left alone. It’s also an eyesore in lawns and flower beds.
Creeping cinquefoil can be weakened more effectively through raking than hand-weeding. Weed killer is effective against heavy creeping cinquefoil infestation. You’ll need to reapply weed killer after about six weeks to keep it from returning. Creeping cinquefoil blooms from June to October.
Scientific name: Euphorbia cyparissias
A bushy ground-covering week that can grow up to two feet tall, cypress spurge is also known as Bonaparte’s Crown, Graveyard Moss, and Graveyard Weed.
The sap of cypress spurge is toxic to grazing livestock and can cause rashes and skin irritation when touched by humans.
Cypress spurge is native to Europe, coming to North America as an ornamental plant. It became so prolific that the European flea beetle had to be introduced to North America to control the growth of cypress spurge.
Scientific name: Taraxacum officinale
Blooming March through November, dandelions are perennial, deeply rooted weeds. Its seeds spread when they’re blown from a spent dandelion blossom. Children often make wishes before blowing dandelion seeds to the four winds.
Dandelion leaves have health benefits, so young leaves are an ingredient in teas and green salads. Dandelion blossoms can be made into wine, making them more useful than the average weed. Still, dandelions will crowd out the grass.
The best defense against dandelions and other broadleaf weeds is to have a thick lawn. Hand-weeding isn’t effective against dandelions because of their long roots. It can take time to remove them once they’ve started reproducing in their yard. Many people just let them grow, keeping their grass regularly cut.
Scientific name: Trifolium aureum pollich
A biennial weed that blooms from June to August, golden clover often grows in meadows but can encroach on yards, too. Golden clover is also known as a Palmate Hop Clover because its aging flowers can resemble hops.
This common garden weed is often the culprit causing thin, patchy lawns. This is because golden clover will crowd out grass and rob it of moisture and nutrients needed for it to be in its best condition.
Golden clover can be pulled by hand. Another method to keep from having a patchy lawn is to fertilize your other plants in the spring and fall so they can better compete with golden clover. But this plant is easily identified, and easy to pull once it’s been seen growing in your yard or garden.
Scientific name: Ficaria verna
A common woodland, garden, and lawn weed with yellow flowers, lesser celandine will spread aggressively. Lesser celandine can reproduce through its root system and is also self-pollinating.
Lesser celandine can be hard to eradicate. Small infestations can be removed by digging up the plants. Larger patches of lesser celandine will need to be mowed after leaves mature but before flowering begins.
Scientific name: Rorippa palustris
Marsh yellowcress can pop up as an annual, biennial, or short-lived perennial, causing problems with vegetable and nursery crops. This weed thrives in wet soil that has plenty of nutrients.
Toothed leaves and small flowers can mean your weed is Marsh Yellowcress. Since it has shallow roots, marsh yellowcress can be easily controlled by removing the plant entirely by hand at the roots.
Scientific name: Plantago lanceolata
The narrow-leaf plantain can be found easily as it will thrive in all types of lawn conditions. Since this weed likes dry, compacted soil and alkaline conditions, their presence may indicate a soil compaction problem. Narrow-leaf plantain isn’t as much of a nuisance in pastureland, but it can be an eyesore in flower beds and on lawns.
Hand-weeding can remove narrow-leaf plantain but be sure to remove all the roots, or it will return. Larger infestations will require herbicide use.
Scientific name: Portulaca oleracea
An annual weed with yellow flowers, purslane can grow up to six inches in height and two feet in width. Purslane is drought tolerant and grows in the summertime heat. Because purslane is so hardy, it can be difficult to eradicate. Technically, purslane is a succulent, so it stores water in its fleshy leaves.
Purslane is edible, cooked, or raw, but before you add purslane leaves to your salad, make sure it has not been treated with an herbicide. Also, be sure that you have purslane and not a similar weed, spurge, which is toxic if eaten. Gardeners tend to see purslane as a nuisance instead of as a wild ingredient for recipes.
Purslane can be pulled by hand from yards, but its seeds can ripen afterward. For this reason, purslane that has been pulled from the ground should be placed in a sealed bag to prevent its seeds from escaping and germinating.
Scientific name: Pastinaca sativa
This herbaceous weed is an invasive plant that can thrive in many different conditions and in dry soil as well as wet. This invasive plant isn’t only harmful to other plants. It can also be a health hazard to humans.
Beware of touching wild parsnip as it can cause chemical burns on the skin, with rashes, blistering, and skin discoloration.
Symptoms from touching wild parsnip can last up to two years, so knowing what it looks like is important. Its yellow-green toothy leaves come in arrangements of three to five leaves off the central stem. Its stalks are topped with clusters of tiny yellow flowers.
Scientific name: Raphanus raphanistrum
Wild Radish can be found in vegetable gardens in the spring and summer in the north and the fall and winter in warmer climates. Wild radish grows in any soil type, and it will compete with vegetables for soil nutrients.
With light yellow flowers that fade to white, wild radish has toothy leaves. Wild radish can be controlled easily by hand-pulling. Keeping your soil’s pH to about 6.8 can limit wild radish growth since it thrives in acidic soil.
Scientific name: Cyperus esculentus
Yellow nutsedge is found in many different settings, including landscapes and turfgrass. Wet soil is particularly vulnerable to yellow nutsedge invasion. This weed is considered one of the world’s worst agricultural pests since it can threaten a wide range of crops and is difficult to control.
The perennial yellow nutsedge and its tiny, spiky, flowers can be limited with tillage. Keeping your lawn trimmed to a proper height and fertilizing it in spring and fall will keep the grass healthy enough to crowd out yellow nutsedge.
Scientific name: Narbarea vulgaris
This weed has dark green, shiny leaves that are up to eight inches in length. Also known as a mustard flower, yellow rocket grows in pastures and farmland but can also be found in lawns and turfgrass.
Yellow rocket is a member of the mustard family, showing thick, dark green foliage and, in the spring, flowers in large clusters.
Since yellow rocket can be a nuisance in landscaping and yards, this weed can be removed by hand if the plants are small. If they aren’t small, you will likely need to pull, mow, and pull some more, eventually removing them over time.
Scientific name: Tragopogon dubius
A broadleaf biennial or perennial with a short life span, yellow salsify can grow up to two feet wide and three feet tall. Yellow salsify loves the sunshine, so watch sunny parts of your yard for this invader. The basal leaves and roots can be eaten, which is why it is also known as wild oysterplant.
To prevent yellow salsify from taking root, mulch garden beds. Yellow salsify can be pulled out of garden beds and lawns by hand. Don’t compost yellow salsify, as its seeds will spread, taking over everywhere you use the compost.
Scientific name: Oxalis stricta
Yellow sorrel can grow up to 20 inches tall. This weed with yellow flowers has light green leaves. Its flowers are small and cup-shaped. Yellow sorrel blooms in summer and fall. Their leaves are shaped like a heart.
To prevent yellow sorrel from popping up in your garden beds, mulch to prevent it and other weeds from taking root. Yellow sorrel can be pulled by hand or sprayed with a broadleaf herbicide during the spring or in the fall.
If yellow sorrel is invading cool-season turfgrass such as Kentucky bluegrass or tall fescue or a warm-season grass such as St. Augustine or Bermuda grass, you can remove it by regularly pulling it, and mowing over it. It shouldn’t take much time to prevent it from returning.
One man’s weed is another man’s wildflower. Some weeds with yellow flowers can be welcome to yards and gardens, but they are still considered weeds in some locations. There are also plenty of weeds with yellow flowers that are just plain pesky and hard to remove. But a few of them can even cause skin irritation, blistering, and lesions if you touch them. These plants can be toxic to animals, too.
Preventing the spread of weeds that are invasive or are a nuisance or a hazard is easier than eradicating them later. Clean boots and gear after camping or hiking in woodland areas, and be sure not to compost weeds that have been pulled from your flower beds and vegetable garden.