Bindi-eye is the common name for a notoriously prickly lawn weed formally known as Soliva sessilis. This invasive species, native to South America, has become a widespread problem in lawns across Australia. The plant’s ability to thrive in turfgrass and produce sharp, painful seeds makes it a significant nuisance for homeowners. This article explores the biology of Bindi-eye and provides strategies for its control and elimination.
Identification and Life Cycle of Bindi-Eye
The Bindi-eye weed is a low-growing, herbaceous annual plant that spreads in a dense, rosette-like pattern close to the soil surface. Its leaves are small, finely divided, and fern-like, often resembling carrot foliage. This prostrate growth habit allows it to avoid damage from regular lawn mowing, contributing to its success in turf.
The weed is a winter annual, with its life cycle beginning in the cooler months. Seeds typically germinate during autumn and early winter, establishing small plants. Throughout the winter and early spring, the plant grows and matures, producing inconspicuous, small, greenish-yellow flowers nestled in the center of the rosette.
Bindi-eye thrives in lawns that are thin, stressed, or suffer from compacted soil and poor nutrition. As the plant matures, its central flower heads develop into spiky seed pods. The plant completes its life cycle by late spring or early summer, dying off and leaving behind a fresh crop of hardened, sharp seeds ready to germinate the following autumn.
Understanding the Spiky Hazard
Bindi-eye is considered a pest due to the sharp, rigid seeds it produces, which are technically a type of dry fruit called an achene. These seeds develop within a compact seed head at the base of the plant, often hidden beneath the leaves. While the seeds are soft during the initial winter growth phase, they harden significantly as the weather warms in late spring.
This hardening process transforms the seed pods into painful burs that become embedded in skin, footwear, and the paws of pets. Each flattened seed is tipped with a serrated spine, which allows it to easily puncture skin and cling to clothing or animal fur, serving as the plant’s effective method of seed dispersal.
The peak nuisance period occurs in late spring and early summer, after the plant has died back and left the hardened burs exposed on the soil surface. Encountering these burs causes immediate pain and can lead to minor localized injury, potentially carrying soil bacteria.
Strategies for Effective Removal
Non-Chemical Methods
Effective Bindi-eye control relies on preventing the plant from setting its spiky seeds. Manual removal is a viable option for small, localized infestations, and is most effective during winter and early spring while the plants are small and soft. The entire rosette must be removed, ensuring the taproot is fully extracted before the seed heads begin to form.
Improving overall lawn health is a foundational strategy, as thick, dense turf naturally outcompetes Bindi-eye. Practices like aerating compacted soil and applying proper fertilization help strengthen the grass, reducing the bare patches where the weed establishes itself. Raising the mower height also helps, as the taller grass shades the soil, making it less favorable for the low-growing weed to germinate and spread.
Chemical Control (Herbicides)
For widespread infestations, selective broadleaf herbicides are the most practical solution. These products are formulated to target broadleaf weeds, such as Bindi-eye, without harming most common lawn grasses. Active ingredients commonly found in these herbicides include dicamba, MCPA, and bromoxynil.
Timing the herbicide application is the most important factor for success, as it must occur before the seed heads harden. The best window for application is late autumn, throughout winter, and early spring, when the young plants are actively growing and vulnerable. Applying the herbicide during this time ensures the chemical is absorbed by the leaves and translocated to the roots, killing the plant before it produces its painful burs.
A second application, spaced a few weeks after the first, is often necessary to eliminate any subsequent germinations. Always follow the manufacturer’s instructions, especially regarding application rates and suitability for specific turf varieties like Buffalo grass. A proactive approach using a combination of cultural practices and timely chemical treatment will offer the most successful long-term control.