Mouse-ear Chickweed (Cerastium glomeratum)
Mouse-ear chickweed is a low-growing annual or short-lived perennial weed commonly found in lawns, sports turf, and pastures throughout New Zealand. It thrives in cool, moist conditions, particularly in lawns that are compacted or poorly drained. Its creeping habit allows it to spread quickly, forming dense mats that crowd out desirable grass species.
Because of its soft, hairy leaves and ability to survive close mowing, it often becomes established in worn or shaded areas where turf cover is thin. It reproduces rapidly by seed and sometimes by rooting at the nodes, allowing it to persist year after year if not properly controlled.
Identification
Mouse-ear chickweed forms small, dense mats with hairy, oval leaves that are paired along creeping stems. The fine hairs give the foliage a grey-green appearance and a slightly sticky texture.
The stems lie close to the ground and can root where they touch the soil, helping the plant spread horizontally. Tiny white star-shaped flowers appear mainly in spring and early summer, each with five deeply notched petals that can make them look like ten.
It’s sometimes confused with common chickweed (Stellaria media), but that species has smooth, non-hairy leaves and tends to have a more upright, delicate form. Mouse-ear chickweed’s dense, hairy mats and creeping stems make it far more resilient under mowing.
Why It’s a Problem
This weed competes aggressively with turfgrass for light and nutrients, especially in areas that are moist, shaded, or compacted. Its mat-forming growth habit can smother grass seedlings and create uneven patches that affect lawn appearance and drainage.
In pastures or recreational turf, mouse-ear chickweed is generally unpalatable and may indicate underlying soil or drainage problems.
Management and Prevention
Cultural control methods:
- Improve drainage: The weed thrives in waterlogged or compacted soils. Core aeration and sand topdressing help prevent it.
- Reduce shade: Encourage airflow and light penetration where possible to favour healthy turf.
- Mow regularly but not too short: Prevents flowering and seed production, though low mowing alone won’t eliminate it.
- Maintain dense turf: Regular fertilising, overseeding, and irrigation strengthen grass cover and reduce establishment opportunities.
Chemical Control:
Mouse-ear chickweed can be moderately tolerant to some common lawn herbicides, so using the correct combination is essential for good results.
Effective options include:
- MCPA/dicamba or 2,4-D/dicamba mixtures – effective when applied to actively growing plants in cool, moist conditions.
- Mecoprop/ioxynil/bromoxynil (Image) – works well on young plants and provides broad control of other low-growing weeds.
- Picloram/triclopyr mixtures (NZLA Gold) – strong control in established turf or pastures.
- Bentazone (Basagran or Pulsar) – another good selective option, particularly in newly sown turf.
Apply herbicides in autumn or early spring when plants are actively growing but before flowering. For long-term control, combine spraying with turf renovation to remove compacted or shaded conditions that favour regrowth.