AgPest » Kikuyu Grass

A rhizomatous plant with long creeping and scrambling stolons
Forms a dense mat and may climb objects in path, such as rocks, fences and shrubs
A C4 plant that grows best over summer and in warmer areas
Frost tender
Leaves are mostly hairless, with slightly rough margins and the top section of the midrib
Ligule composed of 1-2 mm long hairs
Overlapping leaf sheaths with tapering leaves, 3-8 mm long
Flower spikelets hidden in leaf sheaths of vegetative side shoots
Filaments from male and bisexual flowers and the style and stigma of female flowers emerge from sheaths.

Originated from East Africa, adapted to humid tropics and subtropics
Officially introduced onto Northland farms in the 1920s after favourable trials
By the 1950s, it was realised that Kikuyu became weedy when uncontrolled and that eradication was now unlikely
Now widespread in northern half of the North Island and common in coastal areas of the southern half, also in Marlborough Sounds, Nelson, Westland and Canterbury
Grows in pasture, lawns, waste areas, roadsides, coastal areas and waterway banks
Tolerant of dry conditions, can dominate north facing slopes and dry hilltops.

Kikuyu reproduces asexually, through its creeping stolons, and sexually through seed
Spread is primarily by node-bearing fragments of stolon and rhizome, and seeds (often found in cowpats)
Summer/ autumn growth flush, with growth slowing in winter
A new plant (formed from a node on a stolon or from seed) will produce leaves from the crown, and then new leafy side shoots from leaf axils. These side shoots turn into stolons (becoming long and prostrate) which root at the node. New plants can develop from broken stolons
Rhizomes (underground stems) also form nodes and these act in the same way as the stolon nodes; where the rooted node is exposed to sunlight, a new plant can form.

Kikuyu was introduced as a pasture grass and it can produce nutritionally valuable feed if well managed
Useful fodder plant in summer dry areas and on poor soil.

Kikuyu’s autumn flush supresses’ temperate grass species growth, preventing them from producing to their full potential in winter. Intensive management is required to allow other complementary species to grow
If uncontrolled, it can become a weed, producing little in the way of nutritional feed
If unmanaged, it will form a dense mat that can smother small trees and shrubs in orchards, roadside and riparian plantings etc
It has been listed as an environmental weed by the Department of Conservation.

Kikuyu can be controlled using a combination of intensive grazing, mechanical removal, spraying and re-sowing with other species. Some look to prevent kikuyu from forming a single-species mat and instead aim for multi-species pasture where kikuyu is a component of that. Eradication can be achieved using chemical means although recruitment from the soil seed bank is an ongoing problem.

Controlled (strip) grazing and/or a high stocking rate are common when managing kikuyu grass. This allows other species to re-emerge from the kikuyu (and be productive during the colder months) and prevents it from forming an unpalatable mat
Kikuyu that has not been managed correctly (forms a mat) is not productive, and stocking rates will decrease as feed will be short in winter and spring
In frost prone areas Kikuyu will die back during winter and regrow from rhizomes in spring.

Mowing can control kikuyu if it is done before a mat forms. But mowing above 3cm will not impact an established sward and its competitive ability will not be affected
Mulching down to ground level causes the plant to draw on its reserves. If this occurs when kikuyu growth is slowing (autumn), it cannot compete as effectively and its ability to over-winter is impacted. A mulcher with vertical cutting action is more damaging, due to the horizontal growth of the stolons and rhizomes. Mulching will also create smaller fragments that decompose more readily, as opposed to mowing
Mulching should be carried out every year, when the stolons over-top other pasture species and before the kikuyu forms a mat. Too much mulching trash (cut kikuyu) will affect establishment of other species, so it is important that the fragments decompose quickly or are removed
Kikuyu will regenerate in the spring after mulching or mowing.

Ryegrass and other winter growing species can be direct drilled in autumn before kikuyu mulching and improve the pasture production over winter and spring
Perennial ryegrass can be used and will bring down the costs associated with yearly sowing of annual ryegrasses, but care must be taken to ensure that kikuyu does not become dominant in the next summer/autumn (high grazing pressure and mulching)
Clovers will co-exist with kikuyu and red clover has been reported as reducing the summer-dominance of kikuyu.

It is possible to manage kikuyu with chemical control, but it readily regenerates from seed. Many strategies for kikuyu control use chemical control in conjunction with the above methods to produce a pasture where kikuyu provides the bulk of the summer feed.

Active Ingredient	When to apply	Residual effect	Grass damage	Clover damage
Dalapon	During active growing period (summer- early autumn)	Yes	Severe	Moderate
Glyphosate	As above	No	Severe	Severe
Haloxyfop	As above	Yes	Severe	None
Glufosinate-ammonium	As above	No	Severe	Severe
Triclopyr	Autumn, may require retreatment after 4-6 weeks	No	None	Moderate
Nicosulfuron (maize crop use)	Before thick grass layer formed	Yes	Severe	Moderate