Yellow-flowered weeds thrive in lawns like many other weeds because they can tolerate various soil conditions, have rapid growth rates, and efficiently capture nutrients and sunlight.
Additionally, their ability to produce lots of seeds makes it hard to stop the weeds from taking over your lawn.
Lawn weeds with yellow flowers spread their seeds in several ways, depending on the plant.
- Rhizomes are underground stems or roots that run horizontally beneath the soil. These stems help weeds to spread out and pop up in new places sneakily.
- Stolons are aboveground stems that creep along the surface of the soil. These stems act like overground vines, creating paths for weeds to move and cover more space.
- Seeds, often produced prolifically, can be dispersed by wind, animals, or human activities, contributing to the widespread distribution of these plants.
7 common yellow flower weeds growing in your lawn in Australia
Here is a list of common yellow lawn weeds you might encounter in Australia and how to eliminate them. Before removing them, remember that yellow flower leaves can also be beneficial pollinators.
Additionally, proper watering, mowing, and fertilisation help create an environment that's less favourable for yellow-flowered weeds.
Oxalis (Oxalis spp.)
Often referred to as sourgrass or wood sorrel, oxalis is easily identifiable by its clover-shaped leaves and petite flowers in shades of yellow or pink. Creeping Oxalis is known for invading lawns and gardens due to their aggressive and invasive growth habits.
So what kills oxalis but not grass? Removing oxalis manually before it reaches the flowering stage is recommended for adequate control. Hand-pulling is also an efficient method of weed removal.
Alternatively, targeted treatment using a broadleaf herbicide can help manage its growth.
Bin-Die, formulated for buffalo lawns, is versatile across various types like couch, bent, Kikuyu, paspalum, fescue, and rye. This broad-spectrum weed killer targets common weeds, including bindii, catsear, clover, creeping oxalis, cudweed, dandelion, plantain, and thistles.
Catsear (Hypochaeris radicata)
Referred to as flatweed or false dandelion, catsear is a perennial with basal leaf rosettes and produces yellow dandelion-like flowers. This plant can spread quickly.
Manual weeding methods such as hand-pulling or mowing can be implemented for adequate control. In larger infestations, herbicides labelled for broadleaf weeds are recommended as an additional control measure.
Dandelion (Taraxacum officinale)
Dandelions, known for their bright yellow flowers and fluffy seed heads, are common in lawns and are known for their resilience. While the yellow-flowered varieties are frequently found in lawns, dandelion flowers can appear in various colours. These stubborn plants threaten your lawn's health and aesthetics, absorbing a significant amount of the water the surrounding grass needs.
One problem with dandelions is how easily the seeds can spread along the wind. Their deep root system makes getting rid of them a challenge. If the root isn’t removed properly, you can expect quick regrowth.
Hand-digging is effective for minor patches to control dandelions, but the deep taproots make things challenging. Herbicides formulated for dandelion control or a broad lead fertiliser can be used as a last resort.
Burr Medic (Medicago polymorpha)
Burr Medic (Medicago polymorpha) is a common yellow-flowered weed found in Australian lawns. While the vibrant yellow blooms might appear visually striking, Burr Medic can affect the health of your lawn.
This weed competes aggressively for essential resources, such as water and nutrients, with desirable grass species, reducing lawn quality. Burr Medic produces burr-like seedpods, spreading clothing or fur etc.
Controlling Burr Medic in Australian lawns requires a multi-pronged approach. Regular mowing can help manage its growth, but herbicides specifically formulated for broadleaf weed control are often necessary to remove the weed.
Bindii (Soliva sessilis)
Bindii (Soliva sessilis), commonly known as "jo-jo," is a widespread lawn weed in Australia. This broadleaved annual is recognised for its small, prickly burrs, sometimes featuring small yellow flowers. The plant is low-growing and stings when stepped on.
Hand-weeding can be attempted before the burrs emerge but is difficult once germination has begun. To proactively tackle the issue, pre-emergent herbicides applied in early spring can help prevent the germination of bindii seeds and curb their growth before they become a nuisance in your lawn. It's essential to address bindii early in its life cycle to maintain the health and comfort of your lawn.
Clover (Trifolium spp.)
Clover is typically associated with white flowers, although certain varieties, Trifolium dubium may have small yellow blooms.
While gardeners intentionally cultivate clover for its beneficial nitrogen-fixing properties and attractiveness to bees, it can pose a challenge if it takes over your entire lawn.
Hand-pulling effectively controls the weed, especially in smaller patches before flowering. Alternatively, established clover clumps can be treated by spraying a vinegar mixture and a few drops of dishwashing liquid.
Another option is the use of a broadleaf herbicide formulated explicitly for lawns.
Capeweed (Arctotheca calendula)
Capeweed, scientifically known as Arctotheca calendula, is categorised as a broadleaf annual weed. Recognisable by its yellow daisy-like flowers, this weed has the potential to spread rapidly if left to its own devices.
Hand-pulling, especially before the flowering stage, can be successful for small patches of capeweed. Avoid leaving bare patches of ground in late summer, as this *is the ideal environment for growing capeweed. Once capeweed plants start seeding, they can quickly spread, making early intervention key.
In larger areas where capeweed has taken hold, herbicides designed to target broadleaf weeds are a suitable control option.
How to prevent weeds in your lawn
Regular mowing: Regularly maintain your lawn at the recommended height for your grass type.
Proper watering: Water your lawn deeply and infrequently to encourage strong root growth in your grass. Shallow, frequent watering can promote weed growth.
Adequate fertilisation: Feed your lawn with the appropriate fertilisers to promote healthy grass growth. A dense and vigorous lawn is more resistant to weed invasion.
Overseeding: Overseed your lawn with grass varieties well-suited to your region. A thicker lawn leaves less space for weeds to take root.
Hand weeding: Periodically hand-pull weeds as they appear. This is particularly effective for small infestations and prevents them from spreading.