Spurge weed (Euphorbia maculata) is also known as spotted spurge, milk-purslane or prostrate spurge (though not the same as Euphorbia prostrata), is an extremely common invasive weed. It is native to Eastern North America and is often seen growing out of sidewalk cracks and along walkways. It can also take root pretty much anywhere, including roadsides and thin lawns, though it seems to prefer being near rocks or concrete. The seeds tend to germinate in warm soil once temperatures reach 75F consistently. The plant is killed by frost, but the tiny seeds can spread far and wide and many of them will germinate in the spring.
Surge weed contains a toxin in the milky sap that can be released when the stems are broken, so wearing gloves when handling it is advisable.
|Common Name||Spurge weed, spotted spurge|
|Botanical Name||Euphorbia maculata|
|Mature Size||Up to 4 inches, usually prostrate|
|Soil||Any, dry, sandy, compacted|
|Flower Color||Pink or pale green|
|Hardiness Zones||USDA 5-9|
|Native Areas||Eastern North America|
How Invasive is Spurge Weed?
Spurge weed is a common invasive weed that is native to Eastern North America and grows throughout most of the United States, apart from the Southeast due to humidity sensitivity and lack of winter chill hours needed for germination. It spreads via tiny seeds, has a deep tap root, and grows very quickly during the summer months.
This is one of those "grows anywhere" weeds that can be a nuisance, although not as difficult to eradicate as invasive vines or weed trees. Spurge weed likes full sun, and if allowed to spread it can cover other plants and prevent their absorption of sunlight. The roots are somewhat firm and tough, and pulling them out doesn't tend to destroy the tap root which can regenerate the plant quickly, making spurge weed a season-long problem throughout the summer. Spurge weed also seems to flourish in periods of drought.
Identifying Spurge Weed
Spurge weed is usually considered part of the Euphorbiaceae family, and is a relative of the rubber tree and the castor bean. However, it is sometimes classified as part of the Chamaesyce family, referred to as Chamaesyce maculata, and this may cause confusion. Spurge weed has a lacy network of thin stems with small oval blue-green leaves on both sides. Sometimes the stems have a reddish tinge. Spurge weed is known as a "prostrate" plant, meaning it spreads out in a flat oval or wheel shape wherever it grows, instead of growing upwards. It can spread out to a foot wide in some cases, but usually grows to about 6 or 7 inches in diameter. In some spots it may grow upwards in a loose clump 1-4 inches tall. The flowers are very tiny, sometimes a pale pink color, but often appear to be pale green. This plant has a very fast growth cycle, and goes from germination to flower and seed production in just 30 days, making it a challenging weed in the summer season.
Removing Spurge Weed
Spurge weed is quite easy to pull out. But removing every bit of the tap root is difficult as it is very thin and grows deep. More often that not, the weed will regenerate from that taproot. Digging around the plant to loosen the taproot before pulling it may help. Removal is especially tricky when spurge weed grows from areas that can't be dug, such as in sidewalk cracks (though you can try using a hori-hori, or Japanese weeding knife which has a thin sharp edge). Diligently pulling it every time it appears can eventually weaken the taproot and kill it. Non-specific herbicides are an option, but keep in mind these chemicals will kill everything in their path, so only use them on weeds growing up through sidewalk cracks and not near other garden plants or food crops. A safer alternative to herbicides if you have spurge weed growing in sidewalk cracks is pouring boiling water or vinegar over the area. This is especially effective after pulling as it may help kill the roots. Many gardeners simply accept that spurge weed will be a constant presence in their gardens once established, and given how easy it is to pull up and how hard it is to fully eradicate it, it is tolerated as an annoying invasive, but not a particularly noxious one (unlike Oriental bittersweet, buckthorn or poison ivy).
Preventing Spurge Weed
It's hard to prevent growth of spurge weed because it's so ubiquitous and grows easily in such inhospitable conditions. One way it can be introduced to the garden is from nursery plants, where it may be found growing in containers. Always check your nursery plants before transplanting them and carefully remove any weeds. Spurge grows well in compacted soils, where its thin but strong tap root takes hold. Heavy mulching with newspaper or wood chips can also help keep it at bay, but spurge will also sometimes grow on top of mulched areas. Spurge tends to only grown in lawns that are thin, so maintaining a thick healthy turf in rich soil, with regular mowing, watering and regular applications of fertilizer, is a good way to prevent spurge and other weeds from taking up residence. Using a pre-emergent herbicide might help stop spurge weed from germinating, but it should not be used anywhere near where food crops are grown. Similarly, these herbicides are not recommended if you are trying to attract pollinators to your garden. Pre-emergent herbicides are meant to be used in early spring, and to be effective against spurge they should be used before the daytime temperature reaches 60F.
Why is spurge weed so invasive?
Spurge weed produces thousands of tiny seeds that travel easily via pedestrians, animals and wind. It also thrives in thin soil and drought, making it very determined to grow.
Can spurge weed overpower other plants?
Because spurge weed spreads outward in a prostrate manner, it can cover over other plants very quickly, depriving them of sunlight and even strangling or stunting growth.
Are herbicides the best way to control spurge weed?
While non-selective herbicide applied carefully at the young stage of growth may kill spurge weed, it has a long taproot that often regenerates. Removal at first sign of growth throughout the season is the best way to keep it under control. A pre-emergent herbicide may also be used, though must be applied in early spring before temperatures go above 60, and should be avoided near areas where food crops are grown.
Lawn and Turfgrass Weeds: Spotted Spurge - Penn State Extension