Soliva pterosperma

Soliva pterosperma, commonly known as common soliva or lawn burrweed, is a small, low-growing winter annual belonging to the Asteraceae family.

The plant features finely divided, fern-like leaves that form a low rosette, hugging the ground surface closely, which allows it to escape detection by lawn mowers.

Its flowers are inconspicuous and greenish, developing in the leaf axils near the base of the plant, lacking any showy petals or tall stems.

The most distinctive feature of this weed is its fruit, which matures into a hard, prickly burr, equipped with sharp, spine-like structures that protrude from the seed.

These prickly seeds are the primary means of identification in late spring and are responsible for the discomfort caused to humans and animals when stepping on the plant.

Native to South America, Soliva pterosperma has successfully naturalized in many subtropical and temperate regions globally, thriving in sunny, open environments.

It is commonly found in urban settings such as lawns, sports fields, parklands, and along footpaths where the soil is often compacted and traffic is frequent.

The weed favors areas with poor turf density, as it thrives where competition from perennial grasses is reduced due to environmental stress or overgrazing.

In agricultural systems, it colonizes overgrazed pastures and thin forage stands, easily outcompeting native grasses that are weakened by continuous grazing pressure.

It is highly tolerant of low mowing regimes, which makes it a persistent nuisance in managed landscapes that are kept at short heights for aesthetic or functional purposes.

The primary damage caused by Soliva pterosperma stems from its sharp, prickly burs, which can cause significant irritation and physical injury to bare human feet.

In livestock production, the plant is considered a serious pest as the burs can become embedded in animal hoofs or cause painful inflammation of the mouth and tongue.

As an invasive annual, it competes heavily with desirable turfgrass and forage species for essential nutrients, water, and sunlight during the critical early spring growth phase.

The presence of this weed reduces the recreational value of parks and play areas, rendering them unsuitable for activities that involve direct contact with the ground.

Because livestock tend to avoid grazing this plant due to its prickly nature, it gains an evolutionary advantage in pastures, rapidly spreading and reducing the overall grazing capacity of the land.

Effective management begins with cultural practices that promote a dense, healthy turf canopy, which naturally suppresses the germination of soliva seeds by blocking sunlight.

Regular hand-pulling or removal of the rosettes in late winter, before the development of the prickly seed heads, is an effective strategy for small-scale infestations.

Chemical control involving selective post-emergent herbicides is recommended for larger areas, focusing on products specifically designed to target broadleaf weeds in turfgrass.

Application timing is crucial; herbicides must be applied early in the growth season while the plant is young and before it produces its characteristic prickly burrs.

• Improve soil drainage and aeration to reduce compaction.
• Maintain proper mowing heights to encourage vigorous grass growth.
• Monitor and treat patches early in the season to prevent seed bank buildup.