Kikuyu grass, St Augustine grass or Bermuda grass?
Kikuyu grass, St Augustine grass and Bermuda grass are commonly used warm season growing lawn grasses. All 3 make for hard wearing low maintenance lawns in warmer climates, and are so vigorous they seldom require any fertilizer.
Domestic lawns have developed a reputation for wasting water and resulting in fertilizer runoff , which is correct to a large extent, but we must remember the cooling nature of lawns. This is especially important in a warming climate and the heat island effect of cities. With more efficient irrigation, such as sub surface or sprinkler operation at night, water use can be reduced, and fertilizer use can be greatly reduced, changed to organic or eliminated entirely.
One of the most common questions I am asked about lawns is which grass is this. Telling the difference between them by appearance becomes apparent when seen next to each other. The St Augustine grass has broader leaves with a blunt rounded tip, Kikuyu has paler green leaves with a pointed tip and Bermuda grass has a much smaller finer leaf, often deeper grey green in colour.
These grasses also often escape from lawns to become weed species invading native vegetation bushland areas. Perennial grasses won’t be out competed by trees and shrubs and intervention is required to control them in bushland, or even in garden beds if they grow out of the lawn area.
All three are quite susceptible to glyphosate herbicide if applied when the grasses are actively growing during the warm months with adequate soil moisture. Care needs to be taken as glyphosate is a systemic herbicide and will travel along the running stolon and rhizome, possibly killing patches of your lawn when spraying lawn edges.
If you wish to avoid herbicides the cultural method solarization has proved effective but may need repeat attempts. This involves covering the grasses with a sheet of plastic over a period of weeks, with the heat from the sun killing the grass plants.