Becoming familiar with cool season and warm season grasses is a great way for pest managers to begin learning about lawn care.
A large number of different grass varieties are used in domestic lawns and managed turf areas. Turf varieties can be broadly split into two main groups – warm season grasses and cool season grasses. it is very important to know the difference as many herbicides will generally be safe to use on warm season grasses or cool season grasses, but not both.
Warm season grasses
Warm season grasses deliver optimal growth in a temperature range of 26-32 degrees. Coupled with their higher level of resistance to periods of drought, they are the dominant grass types for Australian lawns.
Warm season grasses have a growing season from spring until autumn and growth will often cease altogether, becoming dormant, during winter in the cooler parts of Australia, with the turf losing colour and turning brown. Many warm season grasses send out runners (stems that run horizontally at soil level giving rise to new plants) and so are considered quite invasive. The common warm season varieties include buffalo (main picture, above), kikuyu and couch (bermuda) grasses.
Cool season grasses
Cool season grasses tend to be less common in Australia and more suited to Tasmania, the southern areas of NSW and Victoria, and the Great Dividing Range. They have a preferred growing temperature between 15-24 degrees.
Cool season varieties generally have a peak of growth just before spring, but slow down during summer, before having another growth burst in Autumn. They are highly susceptible to drying out and require significant watering during dry periods, even in cool climates. The common cool season varieties include fescue, ryegrass, bluegrass and bentgrass.
Before applying any pesticide or fertiliser to a lawn it is important to identify the grass variety present and read the product label.