Kikuyu Grass in New Zealand:
History and Agronomy
Northland Kikuyu
Action Group
History
grazing management, at times with the use of the
electric fence, is essential. Autumn and early winter
growth is best eaten off before frosts occur. Most
kikuyu areas, instead of being left a liability, can be
made into an asset.”
Kikuyu grass responded to improved soil fertility and
would allow the presence of complementary species,
Kikuyu grass was introduced into New Zealand by
the Department of Agriculture in the early 1920s as
cuttings from a Rhodesian source, although there
may have been earlier informal releases.
Kikuyu is the anglicised version of the proper
noun Gikuyu, the most populous ethnic group of
tribespeople in Kenya.
Kikuyu grass is native to the African countries
of Burundi, Democratic Republic of Congo
(Zaire), Ethiopia, Kenya, Rwanda, Tanzania
and Uganda. It is now naturalised in northern
and southern Africa, tropical Asia, Australia,
New Zealand, south-west mainland United
States, Hawaii, Mexico, Central America,
South America, Melanesia and Polynesia.
Department of Agriculture officers conducted
trials at Albany (Auckland) and Purewa
(Whangarei) and farmers visiting these trials
were impressed with the growth of the plant
and its adaptation to poorer soils. So cuttings
from the trials were readily distributed around
the northern North Island.
By 1974 it had spread to about 10% of
Northland farmland (some 100,000ha)
Over 1000kg/ha milk solids can be obtained from dairy cows
and it was considered a dominant pastures
grazing on kikuyu for a large part of the year, which has been
species over more than half of Northland proven by the Jagger’s Jersey herd.
farms.
In the 1950s many of its characteristics as
a pasture species were becoming clear and E.H. especially in winter and spring, only if controlled
Arnold, an assistant fields superintendent in the by intensive grazing management or mechanical
Department of Agriculture, Auckland, reported to a means. Its feeding value was high when controlled,
but uncontrolled it became a vigorous weed of low
Grasslands Conference:
“Kikuyu grass is here to stay and is spreading far nutritive value and its eradication was impractical. Its
and wide. Eradication is possible, but at a prohibitive drought tolerance and summer/autumn growth flush
cost. Most areas are left as an uncontrolled menace, was recognised but farmer enthusiasm had waned
but quite a number of farmers are successfully using after the deliberate introduction phase throughout
this grass to their advantage. Regular controlled Northland.
smaller land areas, to
ensure they eat all of the
(kikuyu) grass on offer,
before moving the mob
onto another small area of
fresh pasture alongside.
MAF researcher Graeme
Piggot
edited
the
proceedings of the forum,
which were published
by Gallagher Group
in 1985 under the title
Kikuyu Grass Farming
for High Production. A
second edition with the
same name in booklet
form was published by
Wayne Andrewes, Ian Brown, who was reviewing work for the Sustainable Northland
Pasture of
Farming Fund, and Kikuyu Action Group chairman Murray Jagger on
Whangarei in 1991
Murry’s Whangarei Heads farm.
(ISBN 0-473-01427-0)
and both editions contain
During the 1960s and 70s various research
nearly 100 references to published papers on
stations began detailed investigations into kikuyu
kikuyu grass up until that time.
grass productivity. When electric fencing became
At the Whangarei forum, long-time Waikato-based
commonplace and an effective herbicidal control
farm consultant Vaughan Jones, commissioned by
in glyphosate was available, fears of kikuyu grass
Gallagher, put the NZ experience with kikuyu
“taking over the north” diminished.
grass and electric fencing into perspective. “The
The comments of C. Vallance, a Dargaville farmer,
clear message is that kikuyu grass is a highly
at a Grasslands Conference in Northland in 1967
productive species which can be grown in
are interesting. “Kikuyu is a controversial grass,
balance with other grasses and clovers, provided
and where I once used to envy farmers who had
it is fenced into enough paddocks to allow it to be
none, I no longer do so. Kikuyu, which was once
grazed down in one bite,” Jones said. The widelybrown and unthrifty, is now thriving, and with a
travelled Jones told of Hawaiian problems with
stocking rate of one cow and replacements per
stock underfeeding in the midst of rampant kikuyu
acre (2.5/ha), I am having trouble keeping up
grass. Gallagher power fencing was introduced
with its growing capacity.”
to Hawaii and early adopters increased their
Kikuyu Grass Forum
productivity and profitability from cattle on kikuyu,
In November, 1985 a Kikuyu Grass Forum was while pastures improved as clover re-emerged.
held in Whangarei, organised by the Agricultural Jones concluded with a prototype kikuyu
Research Division of the Ministry of Agriculture management programme, the first of its kind:
and Forestry (MAF) and the Grasslands Division 1.
Intensive subdivision to allow rotational
DSIR, and sponsored by Gallagher Group, of grazing.
Hamilton.
2.
High stocking rates.
Animal management equipment company 3.
Regular mowing of surpluses.
Gallaghers was keen to highlight the use of 4.
Correct fertilising.
controlled, or strip, grazing behind electric fencing, 5.
Inclusion of the most suitable clovers and
both permanent and temporary, to keep on top of winter-growing grasses.
the vigorous growth of kikuyu grass during summer 6.
Mob stocking in autumn to allow winterand autumn months. New Zealand led the way growing species through.
in the development of electric fencing from the
1930s, which became a farm management tool Also at the forum, Northland dairy farmer Danny
to cost-effectively confine grazing animals onto Simms recalled his parlous position with kikuyu-
dominant pastures
before introducing
specialised
management.
Simms said his
kikuyu grass was
rampant, the heavy
clays were very wet
as a consequence
and the soil fertility
was low. The result
was a severe feed
shortage in spring,
low
per
cow
and per hectare
production, low cow
fertility and a spread
calving
pattern.
With management
improvements
Simms
doubled
Inaugural Kikuyu Action Group chairman Murray Jagger addresses
his production per
the crowd at a KAG field day on his own Whangarei Heads Farm.
hectare in a decade
and got 94% of cows
5.
And, finally, never let it get away; mow,
calved in the first six weeks. He blitzed the farm mow and mow again.
with 1.5t/ha of 15% potassic superphosphate,
drained the heavy clay flats (to enable the kikuyu Researchers John Rumball (DSIR Kaikohe) and
grass to be controlled in wet conditions) and re- Graeme Piggot and Hugh Morgan (MAF
sowed after cultivation with Ellett ryegrass, Pitau Whangarei) reported on their trial work with
white clover and Pawera red clover, plus plenty sheep and cattle on kikuyu grass pastures.
of lime and fertiliser.
Rumball could find little difference in sheep
“The kikuyu grass regenerated after three years, production parameters between pasture types.
but the aim was that, with high stocking rates, a The DSIR sheep trials were at about 20 ewes/ha
two-tier pasture would develop with kikuyu grass on gumland soil, and the Dargaville beef trials
providing summer feed and the ryegrass becoming were on podzolised sand soil with bulls at 5/ha
dominant at other times.” He said the red clover and steers at 6/ha, with both soils being naturally
did a good job of preventing the kikuyu grass poorly drained
from becoming summer-dominant. He used beef
“Inclusion of kikuyu grass was of benefit to
cows as mulchers in the autumn, at a stocking rate sheep production from mid-January to mid-March
of 6/ha effective, and introduced mechanical at the highest stocking rate in some years, but
topping from the beginning of March.
it consistently depressed sheep production in the
“The autumn rains should then bring the ryegrass spring and required extra management in the
through the kikuyu much earlier,” he said.
autumn.” Rumball said the strategies necessary
Simms provided his own management list:
to maximise the value of kikuyu grass included
1.
Get the soil fertility high.
a high stocking rate, uniform utilisation through
2.
Drain wet areas.
controlled grazing, delaying of lambing by two
3.
Have a high stocking rate.
to three weeks and doubling the grazing pressure
4.
Establish superior ryegrass and clovers. It in autumn. Kikuyu would also benefit sheep where
is simply not practical to control the whole farm white clover growth is poor in the summer, where
with the mower. The burden must be eased by temperate grasses don’t persist because of low
spraying and re-sowing an area of the farm each nitrogen fixation and summer drought and insect
year.
attack, and where sheep are subject to animal
health challenges such as viral pneumonia and
facial eczema.
Piggot and Morgan also reported that weight
gains in Angus weaner steers and Friesian bulls
in farmlet trials at Dargaville research farm from
1979 to 1985 from kikuyu grass pasture were
similar to those reported from solely temperate
pastures. It was possible, they said, to finish beef
cattle to slaughter weights in 17-18 months for
Friesian bulls and 24-26 months in Angus steers.
“These results were achieved by running sufficient
stock to control kikuyu grass in the autumn and by
feeding supplements in late winter or dry periods
in the summer if weight loss was likely,” they
said.
Insect damage
At the 1985 Whangarei forum MAF research
entomologist Rod Blank reported on the resistance
of kikuyu grass to insect attack, namely Australian
solider fly, black beetle, black field cricket and
cosmopolitan army worm.
Solider fly sucks nutrients from the kikuyu roots
and had been observed to cause severe damage
to small areas of kikuyu grass pasture on volcanic
soils around Whangarei. Longer pasture favours
the build-up of fly populations and the potential
for further outbreaks, although low, must increase
with the spread of kikuyu in pastures.
Kikuyu grass harbours two to six times higher
densities of black beetle larvae than ryegrassbased pastures. Either the moister soil conditions
or the food source in kikuyu stolons are
favourable for black beetle. In most situations,
Blank said, kikuyu grass tolerates high larval
densities. The stolons are well anchored, which
reduced livestock pulling damage. But damage
may occur under drought conditions on light soils.
Blank concluded that insecticidal control of beetle
would be impractical.
Pot trials showed that kikuyu grass was highly
favoured by black field crickets with herbage losses
three to 10 times that of ryegrasses. In the field
the dense mat caused by the stolons provided an
excellent shelter for crickets. This enables crickets
to build up on sandy and volcanic soils which
do not readily crack open and provide shelter
in the soil. In dry years, low to moderate cricket
populations (10-30/m2) can effectively consume
all the dry matter grown over the summer. Under
severe cricket attack, kikuyu grass pastures provide
virtually no summer feed for livestock. Kikuyu
recovers well following autumn rains and the
death of crickets, in contrast with ryegrass-based
pastures where plants are killed and pasture seed
is eaten, preventing pasture recovery.
Army worm infestations of kikuyu grass can occur
following periods of heavy rain or floods, where
these have been preceded by a dry period.
There can be loss of autumn growth and fouling
of pastures. Insecticidal sprays can be used but
their use is seldom warranted, Blank said. Army
worm outbreaks have been linked with outbreaks
of kikuyu grass poisoning in livestock.
In summary, kikuyu grass provides a favourable
A Dexcel photograph of the KAG committee in 2002. From left, Rodger
Cann, Alan Davie-Martin, Annelisa Hackett (Dexcel), Helen Moodie, Roger
Maugham, Murray Jagger, Wayne Andrewes (kneeling).
food source and habitat for these four insects.
Solider fly is potentially the most serious pest
because it can cause the most serious long term
damage, however the risk of outbreaks seems to
be confined to volcanic soils. Black beetle and
black field cricket are the pests most likely to be
encountered in kikuyu grass pastures. Beetle larvae
appear to be tolerated, although there may be a
risk of damage in drought years. Crickets cause
considerable pasture production losses but can
be controlled with baits. In general, kikuyu grass
tolerates insect pest feeding damage and, with
the exception of soldier fly, persists well under
severe attack, eliminating the need for pasture
renovation if kikuyu pastures are desired.
Agronomy
change, increased carbon dioxide will result in
stimulated growth in C3 plants, and C4 plants
will diminish.
The growth pattern of kikuyu grass is as follows:
Seedling – produces leaves from the crown
and then tillers from the leaf axils. New leaves
are produced from nodes on the primary and
secondary tillers.
Stolon – A tiller which becomes long and prostrate
as a result of the internodes becoming elongated.
New tillers and new roots can form at each
exposed node, provided the node has been in
contact with the soil. Branching of stolons occurs
after the node has rooted, the rooted node then
effectively becoming a new plant.
Rhizome – An underground stem which forms
nodes and extends by elongated internodes.
The tip or the rooted nodes can produce leaf if
exposed to light by coming up through the soil
surface.
Flowering of kikuyu grass tends to be stimulated in
the secondary or lateral tillers by severe defoliation
and decapitation of a stolon. In NZ, flowering
tends to peak in late spring. Since controlled
environment studies and field observations have
shown that flowering is not sensitive to temperature
and day length, it is likely that the seasonal
pattern is a feature of the growth pattern of the
plant, i.e. late spring is when the plant produces
Kikuyu grass is a C4 plant, which means it grows
in hotter and drier environments than C3 plants
(like ryegrass). They have different photosynthetic
pathways. C3 plants must open their pores during
the day to capture and metabolise carbon dioxide.
C4 plants open their pores at night and capture
the carbon dioxide when the air temperature
is cooler. During the day, with pores closed,
they use the sunlight to metabolise the CO2.
C4 photosynthesis is a more energy-consuming
physiological process than the C3 metabolism,
but is more efficient
in terms of water (and
nitrogen) use. In hot and
dry conditions it allows
the C4 plant to capture
more CO2 than C3 plants,
and so produce more dry
matter than C3 grasses,
being more vigorous and
drought-tolerant.
As our climate becomes
hotter and drier, C4
grasses have an advantage
because of their efficient
use of water. However, as
carbon dioxide increases
they lose their advantage
because of the energy
cost of their metabolism
in comparison with C3
grasses.
Modelling The way that kikuyu grass grows is clearly illustrated here. It has both sursuggests that under climate face stolons which can develop new roots at the nodes and underground
rhizomes which can grow as much as 3cm per day.
the first “crop” on multi-noded stolons in the NZ
growth season. Feathery stigmas (female parts)
are produced first. If these are fertilised by pollen
and a fertilised ovum has formed than filaments
(the male stamens) are exserted and pollen is
shed. The flower is not seen, only the protruding
stigmas or stamens, giving rise to the plant’s Latin
name of Pennisetum clandestinum.
The early introductions to New Zealand were
of male-sterile vegetative material although there
have been later introductions of seed. Malesterility refers to where the flowers only produce
female feathery stigmas, not the filamentous male
stamens. Because male-sterility was assumed to
be genetically recessive, the implication was
that male-sterility in the New Zealand pastures of
kikuyu would remain a primary factor in its spread.
Spread of kikuyu grass would be by vegetative
means. But kikuyu grass began appearing at sites
where vegetative spread was impossible such as
protected offshore islands. Cow dung pats could
be packed with seedlings. The issue was resolved
in the mid 1980s discovery from research by Hugh
Morgan at Dargaville which showed that malesterility was genetically dominant. This meant that
the male-sterile introductions in the 1920s were
likely to be heterozygous, in other words they
carried the recessive gene for male-fertility. Their
progeny would contain fully male-fertile plants. A
small amount of pollen in the environment from
the later introductions of seed would encourage
much wider seed set. Today male-fertile strains
are common across Northland and the issue of
male-sterile strains has become only an intellectual
curiosity.
Vigorous Growth
Ryegrass is a C3 plant, which must open its pores
during the day to capture and metabolise carbon
dioxide.
The aggressive kikuyu plant flourishes by
establishing itself in thick mats. It prevents new
sprouts of other species from growing and can
even kill small tree saplings. It is resistant to mowing
and grazing due to its strong network of roots,
which easily send up new shoots. It springs up in
turfs and lawns, and can ruin pathways by forcing
itself up between stones and tiles. The plant can
be introduced to new areas on ploughing and
digging machinery, which may transfer bits of the
rhizome in soil clumps. While the grass spreads
well via vegetative reproduction from pieces of
rhizome, it is also dispersed via seed.
Kikuyu grass doesn’t like deep shade and will not
therefore penetrate far into bush or forest. But it
will tolerate some shading, which enables it to
grow up within hedges and bushes, eventually
smothering them.
Kikuyu tolerates a wide range of rainfall
environments although it is poorly adapted to
tropical regions and the suspicion is that it doesn’t
like high night temperatures or prefers diurnal
variation in temperature.
Where soils are suitable, it has become naturalised
in areas with rainfall up to 3,000 mm and down to
800 mm/yr, and performing well under irrigation
in lower rainfall areas. It is moderately drought
tolerant, because of deep root system (to >3 m).
Often found along water courses, it can tolerate
some waterlogging and up to 10 days inundation.
Most active growth occurs during periods of high
humidity. It is more frost tolerant than many warm
season grasses, with only exposed foliage being
damaged at about -2°C. Although tops are killed,
stands survive temperatures as low as -9°C.
“Kikuyu grass should be confined to light sandy
soils subject to only light frosts. It is an exceptionally
good coloniser of raw sand country. Raw sand
is extremely liable to dry out in summer, to such
an extent that normally only annual clovers will
survive. Colonised by kikuyu and especially
if top-dressed, white clover grows well on raw
sand because the kikuyu grass has increased the
moisture content of the top layer of the sand.”
Establishment methods
Kikuyu grass has proven
to be a valuable species
for re-vegetating bare,
areas in Northland; on
west coast sand dunes for
control of wind erosion,
on east coast greywackes
for re-vegetation of slips,
on dry volcanics for revegetation of soil slips,
gullies and sheetwash and
on gumland soils.
Soil
conservator
Lee
Whiley, of the former
Northland
Catchment
Commission, told the
Whangarei forum in 1985
that kikuyu’s tolerance of Agriculture Minister Jim Anderton, second from left, up to his knees in
summer drought and low kikuyu on a Northland farm while on a visit to see the work of the Sustainfertility sites made it useful in able Farming Fund. Providing explanations was AgFirst Northland farm
situations where temperate consultant and KAG treasurer Gareth Baynham, centre, who also works
species
struggled
to for Enterprise Northland and Meat & Wool New Zealand.
survive. Its stoloniferous
habit made it capable of
establishing a rapid cover for controlling surface Acknowledgements
erosion. Farmers used turfs cut from existing Thanks to all the farmers who contributed their time, land,
pasture and dug into the new site. Large areas of stock and machinery. To Northland Seed and Supplies; D
existing turf could be scurfed with a grader blade Boyt Machinery; RD1; Ballance Agri-Nutrients; Dexcel,
and then cut into manageable chunks. Pieces of AgResearch, PGG Wrightson Seeds and NuFarm. To Murray
Jagger and all the other farmer members and non-farmers of
cut stolon could be broadcast over bare areas KAG who have given their time and enthusiasm to attend KAG
and then trampled in by stock. Cattle could also meetings. To the NZ Landcare Trust for project management
be grazed on kikuyu pasture when seeding and and continuity. To the funders who made the work possible:
then moved to the new area, where seed would AGMARDT, Sustainable Farming Fund, FITT fund, NRC,
germinate within the dung pats. Alternatively, Northland Agricultural Field Days Committee, and C. Alma
Baker. Especially to Hinerangi Trust without whose initial
dung which contained germinated seed could be support back in 1999 work would not have started.
collected from cowsheds or yards and spread in
small heaps on eroded areas.
At a Grassland Conference in Tauranga in 1961
J.E. Bell, speaking on Pasture Species and Mixes
for the Auckland Province, said:
Immersed in kikuyu for 30 years
Farm consultant Wayne Andrewes spent 12 years
at DSIR Kaikohe studying kikuyu grass. When the
station closed he managed a 300-cow dairy herd
for four years before becoming a dairy consultant,
based at Kerikeri. During that time Wayne was
retained by Kikuyu Action Group to design and
co-ordinate trials into managing and renovating
kikuyu pastures. He has amassed a wealth of
knowledge about the plant, its agronomy, its feed
value and its management.
Wayne’s first research work on kikuyu began in
1979, looking at the effects of nitrogen on the
botanical composition of Northland pastures. He
recalls that when growing up his dairy farming
father at Kerikeri had a hatred of the introduced
grass, but that it was not a threat in that district at
the time.
Wayne’s own motivation for kikuyu study and
understanding developed when he saw struggling
Northland dairy farmers and share milkers take
over farms on June 1 which had no kikuyu control
during the autumn. “They would then suffer a
shocking spring and a poor milking peak and
two years of financial losses,” Wayne said.
During the 1990s Wayne saw many examples
of disappointment and frustration in controlling
kikuyu, because the farm management skills
being taught were inappropriate. Whangarei
Heads dairy farmer Murray Jagger took the
autumn control message very seriously, adapting
a Gallagher flail mower with a stronger gearbox
Wayne Andrewes, “Mr Kikuyu” describing the
characteristics of the plant to farmers.
and higher revolutions to begin close mulching
kikuyu, not just mowing.
“Murray showed that kikuyu management needed
confidence and timing,” said Wayne. In the early
years of the Kikuyu Action Group the toolbox of
management options was developing, including
spraying, mulching and sowing annuals (see
chapter 5). Wayne realised that the toolbox
improved productivity on kikuyu-dominant pastures
to generate money for regrassing. His life’s work
as a researcher and adviser has been leading
a grasslands revolution in the north, which has
been a very satisfying outcome. Wayne is now
a private farm consultant at Kerkikeri, under the
name Kikuyu Management Ltd.