Suckling Clover (Trifolium dubium)
Suckling clover is a small, low-growing annual clover that often appears in New Zealand lawns during autumn and winter. It germinates as soil temperatures cool, grows through the colder months, and flowers in spring before dying off once summer heat and dry conditions arrive.
While it’s sometimes tolerated or even useful in pastures for light grazing, it’s an unwelcome sight in lawns. Suckling clover forms thin mats of foliage that interrupt the even texture of turf. It thrives where grass is weak—especially in lawns that dry out over summer, are mown too short, or receive little nitrogen fertiliser. Because it can fix its own nitrogen, it often thrives where the lawn is lacking it.
Identification
Like all clovers, suckling clover has three leaflets per leaf (trifoliate leaves). Its leaflets are smaller than those of white clover or subterranean clover and generally lack the white crescent marking commonly seen on white clover.
The plant sits flat to the ground, forming small mats with slender, sometimes reddish stems. Unlike white clover, these stems don’t root along the nodes. The central leaflet is usually held on a slightly longer stalk than the outer two—a subtle but reliable way to tell it apart from other clover species.
In spring, suckling clover produces tiny clusters of yellow flowers, rather than the white blooms of white or subterranean clover. The flowers are small and grouped tightly at the tips of the stems. When mature, the seed pods are smooth and unobtrusive, unlike the prickly burs seen on similar weeds such as bur medick or spotted medick.
Why It’s a Problem in Lawns
Suckling clover competes with grass in thin or under-fertilised areas, particularly during the cooler months. It survives regular mowing, grows flat against the soil, and can quickly spread through patches of weak turf. Because it’s an annual, it will die naturally in early summer, but by then it has already dropped plenty of seed for the next season.
Its presence often points to an underlying issue such as low nitrogen levels, excessive dryness, or low mowing height. Addressing those conditions will make the lawn less favourable for clover growth.
Control in Home Lawns
Suckling clover is relatively easy to control with the right herbicide and some adjustments to lawn care.
Best control methods:
- Physical removal: Small patches can be hand-pulled, especially when the soil is damp. Make sure to remove the crown of the plant to prevent regrowth.
- Chemical control: Use selective broadleaf herbicides containing clopyralid (NZLA BWC), dicamba, or triclopyr/picloram (NZLA Gold) for strong results. These herbicides are highly effective against mature clover. Avoid composting treated clippings for several months, as residues may persist.
- Seedling control: Products like Image (ioxynil + bromoxynil + mecoprop) can help suppress seedlings in early growth stages but are less effective once the plants mature.
- Cultural management: Improve soil nitrogen levels, maintain a healthy mowing height, and water deeply but infrequently to strengthen grass growth. Dense, well-fed turf will outcompete clover seedlings before they take hold.
Prevention Tips
- Fertilise regularly with a balanced lawn fertiliser containing nitrogen.
- Avoid scalping the lawn; leave enough leaf to keep grass vigorous.
- Reseed thin areas in autumn to prevent space for clover seedlings.
- Water deeply rather than frequently to encourage deeper grass roots.
- Aerate compacted areas to promote even growth and soil health.