Weed Management in Emerald

Weed Management in Emerald: Local Conditions and What That Means for Your Property

Weed pressure in Emerald lawns and garden beds is shaped by the combination of acid, moisture-retentive red-brown loam soils, a long growing season, and the constant seed input from adjacent bushland. Winter grass (Poa annua) is the most consistent lawn weed across the suburb. It germinates from late March, establishes through June and July when kikuyu and buffalo are semi-dormant, and produces seed heads before the warm-season grass fills back in. Pre-emergent herbicide applications timed for late February to early March give the best suppression, but the timing is easy to miss in a suburb where autumn-break rains often come late. Capeweed (Arctotheca calendula) colonises any bare patch in lawn, particularly on the more open south-facing aspects of the suburb; it also establishes readily in the red-brown loam of new garden beds where mulch has broken down and the soil surface is exposed. In garden beds, the persistent problems are oxalis (both Oxalis corniculata and O. pes-caprae), which seeds and bulbils through disturbed soil every autumn, and bindi-eye (Soliva sessilis), which sets its spiny fruit in spring on unmulched ground. Kikuyu itself is listed as an environmental weed in Victoria and invades garden beds from lawn edges with particular determination in the moist Emerald soils. It runners under mulch layers and needs physical edging barriers as well as herbicide treatment to keep it from re-entering beds. Around the Cardinia Creek drainage corridors, environmental weeds including English ivy, wandering trad, and sweet pittosporum seedlings invade from the reserve edge and need periodic herbicide treatment to prevent re-colonisation of the adjacent garden areas.