How to Identify and Get Rid of Spurge Weed

Spurge weed (Euphorbia maculata), 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 often grows out of sidewalk cracks and along walkways. It can also take root anywhere, including roadsides and thin lawns, though it prefers being near rocks or concrete. The seeds tend to germinate in warm soil once temperatures reach 75 F 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.

Spurge weed contains a toxin in the milky sap that can be released when the stems are broken, so wear gloves when handling.

How Invasive Is Spurge Weed?

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; if allowed to spread, it can cover other plants and prevent their absorption of sunlight. The roots are 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.

Life Cycle of Spurge Weed

Spurge weed sprouts in late spring or early summer. It grows from a long, thin taproot. It also flowers about two weeks after sprouting and self-seeds. With adequate water, its seeds can germinate throughout the growing season until frost, when it dies.

Spurge seeds can remain viable in the soil for up to eight years, although most will germinate within the first two years. It also spreads through its extensive branching root system that can grow widely along the ground 15 feet from the taproot.

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. It is sometimes classified as part of the Chamaesyce genus called Chamaesyce maculata, which 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 spreads out in a flat oval or wheel shape wherever it grows instead of growing upwards. It can sometimes spread to a foot wide but usually grows to about 6 or 7 inches in diameter. It may grow upwards in a loose clump 1 to 4 inches tall in some spots.

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 30 days, making it a challenging weed in the summer.

Removing Spurge Weed

Spurge weed is relatively easy to pull out. But removing every bit of the tap root is difficult as it is very thin and grows deep. More often than not, the weed will regenerate from that taproot. Dig around the plant to loosen the taproot before pulling it up.

Removal is especially tricky when spurge weed grows from areas that can't be dug, such as sidewalk cracks (though you can try using a "hori-hori" or Japanese weeding knife with a thin sharp edge). Diligently pulling it every time 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.

If you have spurge weed growing in sidewalk cracks, a safer alternative to herbicides is pouring boiling water or vinegar over the area. This is especially effective after pulling, as it may help kill the remaining roots.

Many gardeners 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 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 the 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 sometimes grow in mulched areas. Spurge tends to only grow 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.

A pre-emergent herbicide might help stop spurge weed from germinating, but it should not be used anywhere near food crops. 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 60 F.

Spotted Spurge Weed vs. Other Spurges

All spurges are troublesome weeds, reproducing easily by self-sowing seed. And they all have toxic milky sap. The other types of spurge weed include ground spurge (E. prostrate), creeping spurge (E. serpens), petty spurge (E. peplus), garden spurge (E. hirta), nodding spurge (E. nutans), and thyme-leafed spurge (E. serpyllifolia).

Prostrate spurge and creeping spurge act as groundcovers like spotted spurge. Creeping and prostate spurge can also produce roots along the stem nodes, creating new plants vegetatively as they spread. A good thing about spotted spurge is its spreading stem nodes don't root as its stems branch out.

Unlike prostrate and spotted spurge, creeping spurge has no markings on its leaves. Creeping and spotted spurges produce many small, inconspicuous flowers from late spring through fall, leaving behind seeds where they bloom. They have small purple-brown or maroon splotches at the leaf centers.

Most spurges are full sun plants, while petty spurge is a cool season annual that grows in shady, moist areas. Petty spurge is much less invasive than spotted and creeping spurge species. Garden, nodding, and thyme-leafed spurges are also less problematic than other spurges.