Creeping Buttercup (Ranunculus repens)
Creeping buttercup is a low-growing perennial weed that thrives in damp, poorly drained lawns across New Zealand. It’s easily recognised by its bright yellow flowers and spreading habit. Like white clover, it spreads through stolons (above-ground runners) that root as they go, allowing it to quickly cover large patches of lawn.
This weed thrives in wet, compacted soil where grass struggles to grow, making it a common problem in shady or waterlogged areas. It can tolerate mowing and persists even in short-cut lawns. Once established, creeping buttercup forms dense mats that crowd out grass and other desirable plants.
Identification
Creeping buttercup has three leaflets per leaf, but they’re sharply lobed and deeply serrated—quite different from the rounded leaves of clover. The central leaflet is usually on a slightly longer stalk than the outer two. The leaves are dark green and often glossy, with pale undersides.
During spring and summer, it produces the familiar bright yellow, glossy flowers typical of buttercup species. Each flower has five petals and sits on a short stalk above the foliage. The plant’s stolons creep horizontally across the soil, rooting at intervals and forming new plants.
In winter, these stolons often die back, which can make creeping buttercup harder to distinguish from similar weeds such as hairy buttercup.
Why It’s a Problem in Lawns
Creeping buttercup thrives where lawn grasses struggle—wet, compacted, shaded, or poorly drained areas. It quickly forms thick mats that choke out surrounding grass and leave lawns uneven and patchy.
Because it spreads both by seed and stolons, mowing alone won’t control it. Even if cut back, the runners re-root and continue spreading. The flowers also attract bees, which can be a nuisance in family lawns.
Control in Home Lawns
Creeping buttercup can be controlled successfully with the right combination of herbicide and soil improvement. The key is to address the underlying moisture and compaction problems that favour its growth.
Best control methods:
- Physical removal: For small infestations, dig out plants by hand, removing both roots and stolons. This is easiest after rain when the soil is soft. Any remaining runners can regrow, so recheck the area after a few weeks.
- Chemical control: Use selective broadleaf herbicides containing MCPA, dicamba, or triclopyr/picloram (NZLA Gold) for strong results in lawns. These products kill the foliage and stolons effectively. Avoid mowing for several days before and after spraying.
- Non-selective control: For large or heavily infested areas prior to lawn renovation, apply glyphosate at a moderate to high rate, allow full dieback, then re-seed or re-sod.
- Cultural management: Improve drainage and aeration to prevent re-establishment. Avoid overwatering and regularly feed the lawn with balanced fertiliser to keep grass vigorous enough to compete.
Prevention Tips
- Aerate compacted areas and correct poor drainage to remove the wet conditions buttercup prefers.
- Maintain regular fertilising and mowing practices to keep grass thick and healthy.
- Overseed thin or bare patches after weed removal to stop new stolons from taking hold.
- Water less frequently but more deeply to encourage stronger grass roots and drier surface conditions.