Kikuyu grass, St Augustine grass or Bermuda grass?

Which one do you have in your lawn?

Cenchrus clandestinus Kikuyu grass. Image by author.

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.

Cenchrus clandestinus Kikuyu grass. Image — Flickr Creative Commons.

Cenchrus clandestinus (Hochst. ex Chiov.) Morrone. Previously named Pennisetum clandestinum Hochst. ex Chiov.

Kikuyu grass

From East Africa

Introduced into the USA from Kenya in the early 1900s. The common name Kikuyu was chosen because the grass performed so well in the States, that it was named after the East African Kikuyu tribe people who have a deep knowledge of nature and pastoralism.

Sale of Kikuyu may be restricted in some US counties, because it can potentially become an invasive weed, check with your US Department of Agriculture.

Similar in appearance to St Augustine grass but can be distinguished by its generally paler green colour and its leaf blade has a pointed tip. Its leaves are more folded than St Augustine grass.

Kikuyu will spread by below ground rhizomes and running stolons above ground.

It flowers throughout the warmer months, its flower is inconspicuous being hidden within a folded leaf sheath but the male stamen can appear above the leaves.

Its growing period is during the warm to hot months, and it can be damaged by frosts in winter.

Stenotaphrum secundatum (Walter) Kuntze

St Augustine grass. Called Buffalo grass in Australia and South Africa. Many named cultivars are available such as Sapphire and Palmetto.

From Southern USA and Central Americas.

Similar in appearance to Kikuyu grass but generally has a darker green, often blue green leaf and it has a rounded or blunt leaf tip.

St Augustine grass will also spread by above ground stolons and underground rhizomes. It has the reputation for being more stoloniferous than rhizomatous.

It flowers in summer and the seed head is a thick fleshy stalk.

Its growing period is during the cool to warm months.

Beware it can be susceptible to dicamba broadleaf herbicide.

Stenotaphrum secundatum St Augustine grass, showing rounded leaf tip. Image — Wikimedia Commons.

Stenotaphrum secundatum St Augustine grass. Image — Wikimedia Commons.

Cynodon dactylon (L.) Pers.

Bermuda grass, couch grass, Common Bermuda grass. Many named cultivars are available such as Post Card, Blackjack, La Paloma and hybrids for example Santa Ana which is available as a roll out turf.

From the Mediterranean region.

A creeping grass like the other two species but it has a much smaller leaf than Kikuyu or St Augustine grasses and flowers on a tall, 5 finger like branched flowerhead in summer and autumn.

Bermuda grass will also spread by above ground stolon and underground rhizomes.

Its growing period is during the warm to hot months.

More drought tolerant than the previous two species.

Some people may be allergic to the pollen that Bermuda grass produces, which like olive pollen is a nasal irritant.

Cynodon dactylon Bermuda grass, showing seed heads over white paper. Image by author.

Cynodon dactylon Common Bermuda grass, growing as a roadside weed. Image by author.

Plant author names:

Hochst. = Christian Ferdinand Friedrich Hochstetter, 1825 to 1881.

Chiov. = Emilio Chiovenda, 1871 to 1941.

Morrone = Osvaldo Morrone, 1957 to 2011.

Walter = Thomas Walter, 1740 to 1789.

Kuntze = Carl Ernst Otto Kuntze, 1843 to 1907.

L. = Lucien Linden, 1851 to 1940.

Pers. = Christian Hendrik Persoon, 1761 to 1836.

References:

Coombes, A (ed.) 2009, Dictionary of Plant Names, The Timber Press., Oregon. Book.

Gibbs, J., & Gibbs, R. (2001). Grass identification manual for everyone. Native Grasses Resources Group Inc. Book.

All About Kikuyu Grass|Comparison of Kikuyu Grass (turfgrasses.com)

Whibley, D. J., & Christensen, T. J. (1991). Garden weeds: Identification and control (Vol. 3). Botanic Gardens of Adelaide. Book.