Painted Spurge (Euphorbia heterophylla)
Painted Spurge (Euphorbia heterophylla) is also known as Milkweed, and is an in invasive annual weed of the tropics and sub-tropics. You find this weed 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 because it produces large amounts of seed very rapidly, and is able to tolerate a variety of different soil types. It has a very short life cycle of only 40 to 45 days.
Many herbicides fail to control it, and as a result 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 read this, you will be able to:
- Identify Painted Spurge, Euphorbia heterophylla 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)
Photosynthetic Pathway: Euphorbia heterophylla is a C4 weed.
Flower: The inflorescence of Painted Spurge or Milkweed, 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: Milkweed is up to 60 cm tall, with hollow, reddish-green, smooth, and sparsely branched stems.
Leaf length: Painted Spurge has alternate lower leaves along the stem. The upper leaves are opposite, have an egg shape, and are up to 12 cm long. The leaves are hairless to moderately hairy, and have a pointed tip.
Leaf width: The leaves are up to 7 cm wide
Reproduction: The seed of Painted Spurge releases explosively, and then spread by water, in mud that attaches to vehicles and via animals. Large seed banks develop as seed production is high, and has a high germination rate. Under the right conditions, large populations quickly build-up, and these then form dense canopies that smother turf grass.
Milkweed flowers as early as 30 days after it germinates, and seeds form 20 to 25 days later. Single plants produce up to 100 seeds at once, and over a season produce over 4500 seeds.
The seeds of Painted Spurge are not dormant when they disperse, and under the right conditions germinate immediately. As a result the plant has 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 if livestock eat the leaves or latex it has been known to cause the death of livestock and humans.
Habitat: Painted Spurge is a weed of disturbed areas.
For more information on weeds check out our weed ID Chart.
Control of Painted Spurge.
You can control Milkweed or Painted Spurge by cultural and chemical means, but to successfully manage of this weed, it is best if you adopt an integrated approach.
Cultural Control of Painted Spurge.
If you hand weed seedlings, and repeat this over time it is possible to control this weed. It’s best to begin when plants are young, and before it produces seed. Dispose of any plant material that contains seeds and take it off-site.
You should wash-down vehicles and machinery to remove soil and seed, if you move from areas where Painted Spurge occurs.
Chemical Control of Painted Spurge.
Painted Spurge is resistant to many herbicides, and not easily to control with chemical methods. The aim is to reduce the seed bank 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.
Pre-emergent Control.
- Pendimethalin
- Indaziflam. US work shows that Indaziflam gives pre-emergent control of Painted Spurge. This can only use to prevent Painted Spurge in warm season turf grass.
Post Emergent Control of Painted Spurge.
- 2,4-D. This is safe to use on Buffalo grass.
- Bentazone. This is effective for E. heterophylla control at the 4-6 leaf stage, and is safe to use on Buffalo grass.
- Amicarbazone.
- Metsulfuron. Good post emergent control of Painted Spurge can be achieved with Metsulfuron + 2.4-D (2.4 + 670 g/Ha ) + a non‐ionic surfactant (0.1% or 1ml/L).
Non Selective Control of Painted Spurge.
- Glufosinate-ammonium.
- Glyphosate. You can use Glyphosate as a non selective option to control Painted Spurge or Milkweed. If you use Glyphosate, and water quality is an issue then use ProForce Manta Ray.
The following are non-selective but also have a long term residual and stop any re-growth of Painted Spurge.
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- Renegade. Renegade stops the germination of Milkweed for up to 12 months, and reduces the need for multiple herbicide applications.
- Numchuk Quad. This gives effective post and pre emergent Painted Spurge control for up to 12 months.
- Cortex Duo. Cortex Duo gives a rapid knockdown of Milkweed, and residual control for up to 3 months, and is safe to use around trees.
