Pearlwort identification and control

Pearlwort Sagina procumbens

Procumbent Pearlwort is a low growing perennial weed that can become a major problem in fine turf if left unchecked.

Appearance

This weed has almost a grass-like appearance and can sometimes be difficult to distinguish within a turf area.  Leaves are small, blade-like and narrow and will grow 10-20 mm.  They have a waxy coating that makes them resistant to the effects of selective herbicides.

Flowers are small (2-4 mm across) and have 4 parted white/cream petals they are usually produced between May and September and are found near the ends of branches

Growth habit

This is a low growing weed, unaffected by close mowing and tolerant of wear. It has a fibrous, shallow root system and spreads via underground runners and seed.

Conditions that favour its development

Most common in coastal areas, Pearlwort favours moist conditions and is often found in frequently irrigated turf.

Cultural control

Ensure that turf is strong and healthy with good lawn care practices, avoiding bare areas that provide opportunity for Pearlwort to invade:

• Mow regularly and at a sensible cutting height, appropriate to the grass species and growing conditions.
• Apply fertiliser at appropriate times, as the turf requires, to support healthy growth and good root development.
• Water only if required. Overwatering will weaken the sward and keep the soil moist to encourage the development of the pearlwort plants.
• Maintain good surface drainage, using a combination of aeration and top dressing to maximise surface infiltration and encourage good breakdown of water retentive organic matter.
• Small plants can be removed hand using a knife. Remove immediately, if larger patches are allowed to develop they can be very difficult to eradicate.

Chemical control

Procumbent Pearlwort can be difficult to control with selective herbicides.

Products containing the active ingredient 2,4-D are usually the most effective but more than one treatment will usually be required to give adequate control.

To optimise the effectiveness of the selective herbicide always apply when the grass and weed are growing strongly (usually between April and September).