What is the most suitable grass
to be planted as a lawn grass in the greater Auckland region?
I am confronted with this question daily.
When faced with this question the best thing to do is to look around
and see for yourself which grasses are present and which of the desireable
lawn grass species are dominant, this will tell you which grasses nature
has selected. Those that are dominant are without a shadow of doubt the
most suitable for that particular locality.
As little in nature passes my eagle eye I feel compelled to
share my own personal observations made here in Auckland. In addition
I would like to share some of my experience of warm season grasses gained
in Southern Africa as well as cool season grasses gained in Germany and
the low countries. Over a period of time I have made very close observation
of the grasses found growing in private lawns, public parks, sports stadiums,
as well as in public open spaces, pastures, waste land and construction
sites in and around Auckland.
In particular I have taken note of the frequency of occurrence and
total numbers of plants of the different grass species occuring, in particular
the internationally recognised and grown desirable turf grass species.
I have taken note of the fact that the most frequently recommended
and planted lawn grass specie in this region is perennial rye grass (Lolium
perenne) a native grass specie of the British Isles and Western Europe.
Perennial rye grass (Lolium perenne) is a specie from and best suited to
cool, wet, temperate regions.
My observations made here in Auckland are
as follows:
- Auckland experiences long, hot, dry, humid
summers
- Many areas in the greater Auckland region
have heavy, compacted, clay soils of very low fertility
- In most established lawns I have found a
large number of grass species both desirable and undesirable as well as
a large number of broad leafed weed species, with the exception of well
maintained Kikuyu lawns (Pennisetum clandestinum)
- The most frequently found internationally
recognised and grown desirable lawn species found have been Kikuyu (Pennisetum
clandestinum) followed by various species of bent (Agrostis species)
most probably mostly common and creeping bent, in particular in shaded
central Auckland gardens. In many lawns I have also found traces of fine
leafed Fescues no doubt subspecies and varieties of (Festuca rubra)
- In most established lawns I have found little
or no trace of perennial rye grass (Lolium perenne)
- Newly planted rye grass (Lolium perenne)
lawns are prone to diseases such as red thread and rye grass rust in
the hot humid summer months
- Newly established rye grass (Lolium perenne)
lawns have a very high nutrient requirement and if they are not fertilised
frequently they turn yellow then orange. Slowly patches of the weakened
lawn die out which are soon invaded by other grasses and broad-leafed weeds.
- Newly established rye grass lawns (Lolium
perenne) need to be irrigated frequently and sufficiently during the
hot dry summer months, if not sections soon die off which are soon colonised
by other grasses mostly undesirable species such as Paspalum and broad
leafed weeds such as Plantago lanceolata (plantain) and Bellis perennis
(daisy).
- In well established paddocks and wasteland
I have found very little trace of perennial rye grass.
- On disturbed ground I have found two of
the most successful colonisers to be the desirable lawn grass species,
Cynodon dactylon and Pennisetum clandestinum (Kikuyu) both grasses are
grown extensively around the world in warm to hot climates as lawn grasses.
- In the greater Auckland region the dominant warm
season grass is without a shadow of doubt Kikuyu (Pennisetum clandestinum)
Summer
survival under adverse conditions
Trials undertaken by the NZ Sports Turf Institute
in April 1998 came up with the following results.
There was a severe disease outbreak on perennial ryegrass plots
in January 2000, identified principally as Leptosphaerulina, but other
humidity-related diseases were also present. All 24 perennial ryegrass
cultivars suffered severely from disease outbreak and it was only the
Windsor Green (Cynodon dactylon) and Torpedo tall fescue plots that were
significantly less disease-susceptible compared with the industry standard.
During the period from January to April 2000, unworn ryegrass plots
became so severely damaged by disease and other stress-related factors
(eg. dry conditions, high humidity, pest damage) that it was impossible
to continue with the conventional scoring protocol. In contrast, the Windsor
Green (Cynodon dactylon) and Torpedo tall fescue entries showed superb
summer survival characteristics.
The disease incidence in the summer of 1999/2000 was particularly
damaging across all ryegrass cultivars, a result that highlights the
hostility of the Auckland mid-summer environment for this cool season
species.
Factors to consider are the higher water use requirement and potentially
higher disease incidence of perennial ryegrass relative to Cynodon dactylon
during the summer period
Desirable and undesirable characteristics
of three lawn grasses being investigated
Below I have listed a number of the most desirable characteristics
as well as undesirable characteristics of perennial rye (Lolium perenne),
Cynodon dactylon and Kikuyu (Pennisetum clandestinum)
Perennial rye (Lolium perenne)
Desirable characteristics
- A fast and easy to establish lawn grass
when sown on fertile well prepared soils and supplied with adequate water.
- Establishes well during most of the year
if provided with sufficient water in particular during Autumn and
spring
- Produces a high quality lush green turf
Perennial rye (Lolium perenne)
Undesirable characteristics
- Does not do well in the hot summer months
- Can be devastated by summer diseases
- Has a high vertical growth rate requiring
frequent mowing
- Requires specialist treatment for best results
under the climatic conditions experienced in Auckland
- Has a high nutrient requirement
- Has a high water requirement
- Needs annual overseeding to maintain a good
lawn
- Is susceptible to attack by a number of
fungi
- Requires a high degree of maintenance to
keep it in good condition
- Is easily invaded by weeds in particular
weed grasses.
- Weed grasses can not be eradicated by the
application of an agrochemical
- High cost of maintenance, needs to be constantly
overseeded, needs irrigation in summer, needs regular applications of
agrochemicals during the summer months
- Does not like to be cut short
Cynodon dactylon
Desirable characteristics
- Is a very vigorous grower and is a hard
wearing grass
- Establishes well in the warm humid summer
months on most soils
- Establishes well in sandy and saline soils
- Has a relatively low nutrient requirement
- Has a high drought tolerance
- Has a relative low water requirement, during
much of the summer it would require little or no supplemental watering
to remain in good condition
- Repairs its self readily via runners and
underground stolons
- Requires less frequent mowing due to its
horizontal growth habit
- Produces a fine high quality lawn
- Is resistant to fungus damage
- Is resistant to and repairs well after pest
damage
- Is not easily invaded by weeds
- Weed grasses can be eradicated by the application
of agrochemicals
- Needs no specialised care to maintain a
trouble free lawn
Cynodon dactylon
Undesirable characteristics
- Is dormant in the winter months, this may
or may not be a negative factor as the lawn would not need to be cut
during the cold wet winter months.
- Can only be established during the warm
humid summer months
- Runners will invade into flowerbeds if not
kept in check.
Kikuyu (Pennisetum clandestinum)
Desirable characteristics
- Establishes well from seed during the warm
summer months on most soils
- Produces a vigorous very hard wearing turf
- Has a relatively low nutrient requirement
- Is winter active when supplied with sufficient
moisture
- Is not easily invaded by weeds when given
moderate care
- Has a reasonably low summer moisture requirement,
during much of the summer it would require little or no supplemental watering
to remain in good condition
- Has an excellence rate of recovery after
damage via stolons
- Is extremely drought resistant
- Needs no specialised treatment to maintain
a trouble free lawn
Kikuyu (Pennisetum clandestinum)
Undesirable characteristics
- Can be very invasive readily invading flower
beds
- Has a vigorous growth habit requiring frequent
mowing
My conclusions
If one looks very carefully at the facts as they present themselves
then one must come to the conclusion that we need an urgent re-think
on whether perennial rye grass (Lolium perenne) is the most suitable
lawn grass to be planted by the ordinary home owner in Auckland who wants
a good looking, trouble free, weed free lawn.
It is very clear that Kikuyu grass (Pennisetum clandestinum) makes
as in many other parts of the world a very acceptable very hard wearing,
disease free, drought resistant, trouble free lawn. Kikuyu is without
a doubt the best adapted lawn grass for the greater Auckland region as it
dominates whereever it is present, therefore it should be seriously considered
as an option for most sports turf and lawn grass applications.
There is however other lawn grass options open, an option that I from experience
favour, that is Cynodon dactylon. Cynodon dactylon is most probably the
most widely planted lawn grass in warm to hot climates. Recently some of
the top sports facilities and golf courses in Auckland have been planted
to this fine lawn specie.
The native grass specie Microleana
stipoides var stipoides
makes a great lawn, it is found in many
old established gardens in central Auckland, it is reasonably drought resistant
and does especially well in areas of partial shade.
References
Auckland Cultivar Trial Results Dr Richard Gibbs
and Alex Glasgow
NZ Sports Turf Institute, Palmerston North and Auckland
First published in the New Zealand Turf Management Journal, Nov 2000.
http://www.nzsti.org.nz/Cultivar.htm
Selecting the right grass for sand carpet sportsfileds
in New Zealand, by Blair Christiansen, NZ Sports Turf Institute Auckland,
New Zealand Turf management Journal Feb 2006, vol 21, No. 1
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