Petty Spurge (Euphorbia peplus)

Photosynthetic Pathway: Petty Spurge is a C3 weed.

Category: Annual Broadleaf (Dicot)

Flower: The small flowers of Petty Spurge are yellow to green and held in leafy bunches. The unusual flowers of Petty Spurge appear between April and October

Height: Petty Spurge is up to 40 cm in height and has smooth, hairless stems that are red at the bottom and green at the top.

Leaf length: Petty Spurge has thin, soft oval leaves that are rounded to obovate, pale green, and 4 to 25 mm long.

Leaf width: The leaves of Cancer Weed are 4 to 17mm wide

Reproduction: Petty Spurge reproduces by seeds that disperse by water and soil movement. Plants produce between 260 to 1,200 seeds, and these are mature in 12 to 14 weeks.

Seedlings emerge through the year except over the Winter. Most of the seed germinates within a year at a depth of 5 to 10 mm, and after this only a few seeds emerge in the next 5 years. Any seeds that Petty Spurge produces in the Summer germinate immediately, but Autumn seeds stay dormant until the Spring.

Cancer Weed seeds disperse explosively, and these are still viable after 100-years

Comments: Petty Spurge has a milky white sap.

Habitat: A common weed around buildings, gardens and disturbed areas, it prefers moist, shady locations.

For more information on weeds, check out our weed ID Chart.

You can control Cancer weed by cultural and chemical means, but you can best manage this weed with an integrated approach.

• One of the best ways to prevent Petty Spurge (Euphorbia peplus) in turf, is to maintain a competitive stand of grass. This weed is not a very strong competitor and gains a foothold by being an opportunist.
• When open areas develop due to stress, disease, lack of fertility, insects, or high wear, light penetrates to the soil surface, and allows Petty Spurge to germinate. That’s why you also find this weed in open garden beds, paths and areas where it doesn’t need to compete with other plants.

Once Petty Spurge establishes, its too late to control it with cultural practices. For example, at this stage mowing doesn’t work as Petty Spurge tends to grow close to the ground.

• If you raise the height of cut when you mow to 50 mm or more in tall fescue or perennial ryegrass it reduces initial invasions.
• Check the thatch levels of your turf. Thatch should be less than 12 mm.
• Constantly monitor problem areas, so you can hand pull new Petty Spurge before it seeds. Take care as you weed, since plants that you hand pull often break at the stem. This then leaves the root and several buds or a single stem from which it regrows.
• Hand weeding is effective on small areas to control seedlings. It’s best to begin when plants are young, and before plants seed.
• Wear gloves when you hand weed Petty Spurge, since the sap is a skin irritant.

Cancer Weed (Euphorbia peplus) is resistant to many herbicides, and is not easy to control by chemical methods. The aim of control with this weed is to reduce the seed bank and keep it at a low level.

Pre-Emergent Herbicides.

Pre-emergent weed killers prevent Petty Spurge if you use these before seeds germinate in the late Winter. You need to time the application so that it occurs before soil temperatures get higher than 16°C at a depth of 25 mm.

Pre-emergent options for Petty Spurge include:

• Pendimethalin (Battalia 435).
• BASF Freehand.
• Isoxaben (Gallery).
• Dithiopyr (Dimension EW).

Home gardeners can only use Battalia 435, Dimension EW and BASF Freehand for Petty Spurge.

• US work has shown that Indaziflam gives good pre-emergent control of Painted Spurge, which increases the options for control in warm season turfgrass.

Post emergent options include:

• Warhead Trio.
• 2,4-D. 2,4-D and its combinations are not very effective vs large, mature Spurge plants.
• Bentazone.
• Amicarbazone.

Non Selective Petty Spurge Herbicides.

Do not use any of these on lawns or turf areas to selectively remove Petty Spurge.

Table of Non Selective Petty Spurge Herbicide Options.