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Burr and Thistle Weeds that Cause Prickles in Grass (Australia)

Having a lovely green lawn is no good if it’s invaded by burr and thistle weeds.

Featured Image: Burr Medic (Medicago polymorpha) / Photo by Harry Rose / Flickr (cropped) / CC BY 2.0

Prickles on your lawn mean that no one can walk on it in bare feet, not even the dog. In fact, burrs that get embedded in a pet’s paw can be very painful and cause infections and other problems.

Therefore, you want to be aware of the different types of burr and thistle weeds so that you can easily identify them and deal with them as soon as they come up.

Bindii (Soliva sessilis)

soliva sessilis 2 | Weed control
Soliva sessilis (bindi) / Photo by Josep Gesti / Wikimedia (cropped) / CC BY-SA 4.0

This weed is commonly found in lawns around Australia. It’s a broadleaf weed that has carrot-like leaves and forms a rosette.

After flowering, the weed produces a seed capsule that has spurs. This is prickly and quite painful to walk on. 

This means that walking barefoot on a lawn that has bindii is almost impossible.

How to control Bindii

soliva sessilis 3 | Weed control
Soliva sessilis (bindi) / Photo by Harry Rose / Flickr (cropped) / CC BY 2.0

The best way to get rid of bindii from your lawn is to use a broadleaf herbicide, especially in autumn and winter.

Burr medic

Burr Medic Medicago polymorpha | Weed control
Burr Medic (Medicago polymorpha) / Photo by John Tann / Flickr (cropped) / CC BY 2.0

This common lawn weed has serrated green leaves that grow together in groups of three. The creeping stems can be reddish in colour. It produces small pea-sized flowers that are usually yellow in colour

After flowering, the seed pods form as small green pods. These will dry out, become brown, and are prickly. The weed is spread through seed dispersal.

Medicago polymorpha fruit NC11 45869974984 | Weed control
Burr Medic (Medicago polymorpha) / Photo by Macleay Grass Man / Flickr / CC BY 2.0

Burr medic can look somewhat similar to clover and oxalis. The plant has quite a deep tap root which helps it to survive during periods of dry weather.

How to control burr medic

Burr Medic Medicago polymorpha 1 | Weed control
Burr Medic (Medicago polymorpha) / Photo by Krzysztof Ziarnek / Wikimedia / CC BY-SA 4.0

Burr medic is usually easily controlled by regular mowing. This effectively removes the flowers and seed heads or stops them from forming in the first place. 

This weed is also fairly easy to pull out by hand. However, you want to try and do this before the flowers and seed heads form. It’s a good idea to wear garden gloves when doing this.

If you have an out-of-control infestation of burr medic in your lawn, you can also kill it with an effective broadleaf herbicide such as Bow & Arrow.

Thistle

Onopordum acanthium | Weed control
Thistle (Onopordum acanthium) / Photo by Krzysztof Ziarnek / Wikimedia / CC BY-SA 4.0

If you’ve ever touched a thistle, you’ll know that this is a weed that you want to eradicate from your lawn. It has long serrated leaves with sharp spines around the edges.

The flowers are normally bright purple and the weed can grow relatively tall if left uncontrolled.

How to get rid of thistle

Onopordum acanthium | Weed control
Thistle (Onopordum acanthium) / Photo by Salicyna / Wikimedia / CC BY-SA 4.0

Regular mowing should help to control the thistles in your lawn. However, the weeds are also fairly easy to remove manually if you have a good weeding tool. Be sure to wear gloves when you’re doing this.

You can also treat a thistle outbreak with a broadleaf herbicide such as Bow & Arrow.

Khaki weed

Khaki weed Alternanthera pungens | Weed control
Khaki weed (Alternanthera pungens) / Photo by J.M.Garg / Wikimedia / CC BY-SA 4.0

This is a low-growing weed that can form a dense mat if left uncontrolled. It has hairy creeping stems and dark green leaves that grow in opposite pairs. One leaf of each pair is usually larger than the other.

The weed produces greenish-yellow flowers that harden into sharp prickles.

In northern parts of the country such as northern Queensland, northern Western Australia, and the Northern Territory, it is regarded as a priority environmental weed. 

How to get rid of khaki weed

Khaki weed Alternanthera pungens 1 | Weed control
Khaki weed (Alternanthera pungens) / Photo by Forest & Kim Starr / Flickr / CC BY 3.0 US

You can dig the weed out of your lawn but remember to wear gloves. You have to ensure that you get the entire tap root, so be sure to use a good weeding tool. Make sure that you put the weeds into the bin or burn them.

However, because any part of the root that remains in the soil can easily regrow, it’s better to spot-treat this weed with a heavy-duty herbicide that contains glyphosate. Just be careful not to get any of the herbicide onto your grass.

Stinging nettle

Stinging nettle Urtica dioica | Weed control
Stinging nettle (Urtica dioica) / Photo by Randal / inaturalist, Wikimedia / CC0 1.0

Stinging nettles usually grow in nutrient-rich soils and aren’t that common in lawns unless the grass has been left to grow wild and hasn’t been mown for some time.

The leaves of this weed have serrated edges and are covered with fine hairs. It’s these hairs that will cause a burning sensation if touched by the skin.

How to get rid of stinging nettle

Stinging nettle Urtica dioica 1 | Weed control
Stinging nettle (Urtica dioica) / Photo by Steinsplitter / Wikimedia / CC BY-SA 4.0

If you do happen to have some stinging nettles in your lawn area, it’s a sign that the soil is healthy and rich in nutrients.

To get rid of this weed, it’s best to just put on a pair of sturdy gloves and pull it out by hand. Make sure you’re wearing long sleeves as well.

Unlike many other weeds, nettles can be added to your compost if you remove them before they’ve started flowering or seeding. They are high in nitrogen, magnesium, and iron and will give your compost a healthy boost.

However, if the nettles have gone to seed, you can also make compost tea from them to feed your plants. All you have to do is soak them in water for a few days.

The liquid that remains after you take out the steeped nettles with be rich in nutrients. Mix this in the ratio of 10 parts water to 1 part concentrated liquid and feed it to your plants.

Photo of author

Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.

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2 thoughts on “Burr and Thistle Weeds that Cause Prickles in Grass (Australia)”

  1. We had burrs called Bohanna beauties ( not sure of spelling) but they were nasty, can you tell me their species name please

    Reply
    • Hi Chris

      I can’t find any information on the burr that you mentioned. Your best bet would be take a sample either to your local nursery or state agricultural department for proper identification.

      Reply

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