Painted Spurge (Euphorbia heterophylla)
Painted Spurge is also known as Milkweed, and is an annual weed in tropical and sub-tropical regions. You find this in crops, orchards, gardens, pastures, waste and disturbed areas, and along roadsides and drainage ditches. It is in the same family as Petty Spurge.
The invasiveness of milkweed is due to its ability to produce a large amount of seed very rapidly, and to tolerate a variety of different soil types. Its life cycle is short, only 40-45 days.
Many herbicides fail to control it and hence it has spread rapidly in many parts of the world.
Painted Spurge has an allelopathic effect on certain plants.
The distribution map for Painted Spurge is courtesy of The Atlas of Living Australia.
After you finish reading this, you will be able to:
- Identify Painted Spurge or Milkweed.
- Know the habitat of Painted Spurge or Milkweed.
- Know the best cultural and chemical options to control Painted Spurge.
How to Identify Painted Spurge.
Category: Broadleaf (Dicot)
Flower: The inflorescence is a cluster of many, short-stalked, cup-shaped structures at the end of the stems and side branches. The flowers are yellow or green.
Height: Up to 60 cm tall, with hollow, reddish-green, smooth, and sparsely branched stems.
Leaf length: The lower leaves alternate along the stem, whilst the upper leaves are opposite, egg-shaped, and up to 12 cm long. The leaves are hairless to moderately hairy, with pointed tips.
Leaf width: The leaves are up to 7 cm wide
Reproduction: Seed which releases explosively, and spreads by water, in mud and attaches to vehicles and animals. Large seed banks develop as seed production is high, and, with high rates of germination. Large populations form rapidly under the right conditions, and form dense canopies over turf.
Plants flower as early as 30 days after they germinate, and ripe seeds form 20 to 25 days later. Single plants may produce up to 100 seeds at once, and produce over 4500 seeds over a season.
The seeds are not dormant when they disperse and can germinate immediately under the right conditions. The plant can thus perform 4-5 cycles in one season. Germination occurs, at least up to 10 cm below the ground surface.
Comments: The hollow stems have a milky (latex) sap. The latex is very toxic, and eating the leaves or latex has been known to cause the death of livestock and humans.
Habitat: A weed of disturbed areas.
For more information on weeds check out our weed ID Chart.
How to control Painted Spurge.
You can control Milkweed by cultural and chemical means, but successful management of this weed is best if you adopt an integrated approach.
Cultural control.
Hand weeding is effective on small areas where follow-up is possible to control seedlings. It’s best to begin when plants are young, and before seed production. Any plant material that contains seeds should be taken off site and disposed of.
Treat vehicles and machinery, if moving from areas where the weed occurs to weed-free areas, and wash to remove soil and seed.
Chemical control of Painted Spurge.
Painted Spurge is resistant to many kinds of herbicides, and not easily controlled by chemical methods. The aim of control with this weed is to reduce the seedbank and keep it at a low level. On this basis the pre-emergent herbicide BASF Freehand is worth looking at. This is registered to control Euphorbia spp.
Other options include: 2,4-D, Bentazone, Amicarbazone, Glufosinate-ammonium and Pendimethalin, and Glyphosate.
- Bentazone at 480 g/ Ha was effective for E. heterophylla control at the 4-6 leaf stage.
US work has shown that Indaziflam gives good pre-emergent control of Painted Spurge, which increases the options for control in warm season turfgrass.
Alternatively good post emergent control of Milkweed be achieved with Metsulfuron + 2.4-D (2.4 + 670 g/Ha ) + a non‐ionic surfactant (0.1% or 1ml/L)
You can use Glyphosate as a non selective option to control this weed. If you use Glyphosate and water quality is an issue then we recommend the use of ProForce Manta Ray.
