Cat's Hair or common spurge. breaking the stem reveals sap
asthma weed or Cat's Hair
common spurge, cat's hair or asthma weed

Asthma Weed (Euphorbia hirta)

Asthma Weed is also known as Common Spurge or Cats Hair.

After you finish reading this, you will be able to:

  • Identify Asthma Weed and Common Spurge.
  • Know the habitat of Common Spurge or Cats Hair.
  • Know the best cultural and chemical options to control Cat’s Hair.

Common Spurge  is a short-lived soft leaved plant that produces a few, spreading to almost upright reddish stems. It usually grows up to 40 cm tall, and its stems have a cover of yellowish hairs and contain a milky sap.

Asthma Weed has its name because it treats asthma and several lung diseases. This plant is effective against several diseases, such as worms, dysentery and colic, warts, asthma, bronchitis and dengue fever.


How to Identify Asthma Weed.

Asthma Weed or Common Spurge is an annual stemless or short stemmed weed. It has tap root and a basal rosette of leaves about 500 mm wide. As it grows, it sends out stolons and quickly spreads across the ground.

Category: Broadleaf (Dicot)

Flower: Common Spurge flowers from Spring to Summer. The flowers are in the upper leaf forks. These green/yellow/creamy coloured flowers look like dense rounded clusters.

Height: Up to 40cm

Leaf length: It has paired leaves which are 4-50 mm long. They have a dark green/reddish colour with purplish markings. These leaves are on short stalks about 1 to 3.5 mm long and have a fine-toothed margin.

Leaf width: Leaves are 2-24 mm wide.

Reproduction: Reproduces by seed and creeping stems that root at the stem joints.

Comments: Both the upper and lower leaf surfaces have a cover of close-lying hairs. But, as the plant matures it loses the upper leaf hairs.

Habitat: Common Spurge is a weed of verges, footpaths, lawns, bare areas, and playing fields.

Asthma Weed is a good soil indicator weed of compact soil, and bare or thin lawns. For more information check out our weed ID Chart.




How to control Asthma Weed in your lawn.

You can control Cat’s Hair by cultural and chemical means.


Cultural control:

Hand pull or use a weeding tool. You must remove all the roots of Asthma Weed, and dispose of them to avoid re-growth.

Chemical control:

Chemical control options are pretty limited for this weed. BASF Freehand will suppress this as a Pre-emergent herbicide. Non selective options include Glyphosate (Rapid Fire 800). If you use this and water quality is an issue then we recommend the use of ProForce Manta Ray.