Paspalum (Paspalum dilatatum) is a perennial grass weed that causes problems on lawns throughout the North Island of New Zealand. ( Note that this is significantly different plant to the turf variety known as Seashore paspalum) It is a problem in summer when it produces large numbers of seed heads and its low growing wide leaves hug the ground tending to smother other desirable species. It is dormant for the majority of winter, though the crowns are often still visible in lawns that are cut at a low mowing height. These seed heads are similar to some other types of annual summer grass, which tend to be prominent at the same time of the year. The leaves are dark green in colour and are hairless with the exception of two tufts the at emerge at the base of each leaf blade.
- Ryegrass lawns: Methylarsinic acid (Pasma) is effective if used in November or December. Be aware that Pasma will take out fine fescue grasses also. This is an arsenic based product and therefore it is highly poisonous. For that reason it is not recommended for residential lawns. It is a registered product and as such it can only be sold or applied by a registered user. Additionally, the registered user must have a Stage 2 applicators certificate. The alternative solution is to spot spray the paspalum using Roundup or a similar Glyphosate based product when the plants are actively growing and re-sow those areas in autumn. Fine Fescue lawns: Apply Haloxyfop -P-methyl (Ignite, Gallant) at 50mls per 100m2 when the paspalum is actively growing. Given that this is a high label rate, it is recommended that the Gallant is preferably used as a spot spray treatment otherwise some damage will occur to the lawn, particularly if the lawn is under heat or moisture stress. Other Lawn types: Spot spray the paspalum using Roundup or a similar Glyphosate product when the plants are actively growing and re-sow those areas in autumn.If the paspalum infestation is heavy then we recommend spraying the entire lawn with roundup at 50mls/100m2 preferably twice 21 days apart to ensure an effective kill and then re-sow the lawn.