Kikuyu Grass (Cenchrus clandestinus).
Kikuyu Grass is a warm season perennial grass. Cenchrus clandestinus (previously Pennisetum clandestinum), is a tough, mat forming grass, and is an aggressive weed in some situations.
In warm weather it spreads quickly by both stolons and rhizomes. These invade nearby surfaces, and crowd out desirable turf species. Over time it develops an undesirable thatch layer of rhizomes or stolons.
Kikuyu Grass is a native of East and South Africa, and you find this grass almost entirely in areas where the minimum average temperatures are above 16°C.
After you read this, you will be able to:
- Identify Kikuyu Grass.
- Know the habitat of Kikuyu Grass or Cenchrus clandestinus.
- Know the best cultural and chemical options to control Kikuyu Grass.
Why is Kikuyu Grass a Problem?
- It shades out and chokes other plants.
- It grows rapidly in warm conditions and is relatively tolerant of cool weather.
- Kikuyu Grass produces toxins that kill competing plants.
- It is resistant to mowing due to its strong network of roots, which easily send up new shoots.
- It damages buildings by growing in the gaps between stones and tiles.
- When livestock consume large quantities of Kikuyu it causes staggers.
Kikuyu is very fast growing, and its a common problem in Buffalo Grass. These both look similar, so quite often you can’t see the Kikuyu until it’s too late and much of the lawn in now kikuyu.
Other Fast Growing Weed Grasses.
- Paspalum.
- Onion Grass or Guildford Grass.
- Summer Grass.
- Crowsfoot Grass.
- Ryegrass.
- Wintergrass.
For more information, please check out our weed ID chart.
The Distribution map of Kikuyu grass in Australia is courtesy of The Atlas of Living Australia.
Kikuyu Grass Identification.
Category: Kikuyu is a C4 Grass.
Flower: Seed heads form from the Spring through to the Autumn. You can see these as two to four orange spikelets between 3 to 5 mm long.
Height: It grows to a height of 7 to 15 cm.
Leaf Length: The leaves of Kikuyu are up to 5 cm long.
Leaf width: Kikuyu leaves are 3 to 7 mm wide.
Reproduction: Kikuyu Grass spreads vegetatively and by seed. Rhizomes continue to grow as separate plants if you snap them off when you attempt to remove this grass.
Comments: The leaves are hairy, light green with a folded venation. They have a hairy ligule and sheath.
Habitat: Kikuyu Grass is a good indicator weed of very low Ca and P, high K, and very high Mg and Fe. You commonly find this weed in gardens, lawns, roadsides and waste areas.
Kikuyu Grass Control.
Cultural Control.
You can control Kikuyu Grass (Cenchrus clandestinus), and even completely eradicate it by cultural means, but it isn’t easy and takes time.
Hand Removal of Kikuyu Grass.
- The nature of Kikuyu Grass makes hand removal of large infestations very difficult, and it will take repeated efforts to successfully deal with it.
- It’s important that you remove all the stolons and underground rhizomes. This is because any stolons or rhizomes that remain are likely to re-grow into new plants.
- Any material you dig up, you need to remove off-site.
Chemical Control of Kikuyu Grass.
You are best to spray Kikuyu when it is young, and actively growing. If you spray when the plant is under stress the herbicide will not be taken up.
Pre-emergent Control of Kikuyu Grass.
Due to the nature of Kikuyu there are no pre-emergent herbicides registered in turf to prevent Cenchrus clandestinus.
Post Emergent Control of Kikuyu Grass.
Several post-emergents are available for Kikuyu control.
- Ethofumesate.
- Trifloxysulfuron (Recondo 100WG). This only suppresses Kikuyu Grass. Use with a NIS like Optispread 1000.
- Quinclorac (Quinstar). This only suppresses Cenchrus clandestinus. Use with an MSO, and is safe on cool and warm season turf.
- Topramezone (Pylex). Not on warm season turf.
- MSMA (Geronimo). Repeat applications.
- Triclopyr. Not currently registered in Australia for use in turf.
- Foramsulfuron (Tribute Selective Herbicide). Safe on couch. You can increase the uptake and translocation of foramsulfuron by pre-treatment with MSMA.
US research shows that MSMA, and Quinclorac do not control Kikuyu when you apply these only once. However, if you apply these every 4 to 5 weeks over a 5 month period, you will reduce the Kikuyu grass. Sequential applications of two-way combinations of these herbicides in 1991 gave reductions of kikuyu grass from 80% to less than 1% of the sward.
Further work at the University of California shows that a tank mixes of Triclopyr + Quinclorac + MSO or Quinclorac + Carfentrazone + MSO are safe to use on perennial ryegrass and mixed perennial ryegrass/Poa annua. The former mix is NOT safe to use on couch as it will damage it.
Kikuyu Herbicides.
Product | Active | Chemical Group | Rate | Comments | |
Pylex | Topramezone | 27 | 0.375 mL/ 100 m2 in 4-6 L water + 0.5% MSO | Apply to actively growing weeds. Two repeat applications 21-28 days apart are required for optimum control. Some minor transient bleaching of Bentgrass may be observed 7-14 days post application. For best results do not water or irrigate for 24 hrs post application. | |
Geronimo | MSMA | 0 | 3-6L/Ha | 6 L/ha in 300 L of water for boom application or 3 L/ha applied twice approximately 10 days apart | |
Quinstar | Quinclorac | 4 | 4.1 L/Ha | For kikuyu suppression, apply twice, 14 to 21 days apart. Best results are gained from Autumn applications. The addition of a crop oil adjuvant may improve weed control in unfavourable weather conditions. | |
Recondo | Trifloxysulfuron | 2 | 300g/Ha | For kikuyu suppression, make two applications 21-28 days apart, ideally in the Autumn. | |
Tribute Selective Herbicide | Foramsulfuron | 2 | 2 L/Ha | Apply three times at 14-day intervals. | |
Non Selective Control of Kikuyu.
You cannot use any of these on lawns or turf areas to selectively remove Kikuyu Grass.
- Glufosinate-ammonium provides control for 4 to 6 weeks, but it regrows and recovers due to the limited movement of glufosinate.
- Glyphosate. You can use Glyphosate but if water quality is an issue then use ProForce Manta Ray. When you spray Kikuyu with Glyphosate you’ll get best results if you DO NOT add a wetter/penetrant. On dense infestations if you first cut it and then spray the more vigorous fresh regrowth you get better results.
These are non-selective but also have a long term residual and stop any re-growth of Kikuyu.
- Renegade. Renegade stops Kikuyu seed from germinating for up to 12 months.
- Numchuk Quad. This gives post and pre emergent control for up to 12 months.
- Cortex Duo. Cortex Duo gives a rapid knockdown of Kikuyu Grass, and residual control for up to 3 months. It is also safe to use around trees.
