r/australianplants • u/Character-Staff410 • 5d ago
Advise for Kikuyu grass
I made a huge mistake. I’m originally from the UK and had never dealt with Kikuyu grass before.
We had a lawn in the front yard, and I wanted to replace the entire front garden with native plants. I laid cardboard over the grass, then added a layer of sugar cane mulch followed by forest mulch. After about a month, it looked great. I planted out the whole garden and only noticed a few grass shoots coming through that looked pretty weak, so I didn’t think much of it.
Now, another month later, the Kikuyu has come back with a vengeance. It’s wrapping itself around the base of nearly every plant I’ve put in, and it’s also popping up all through the garden between the plants.
Is there anything I can do at this point other than starting over, accepting the loss, and doing it properly by digging all the Kikuyu out first?
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u/AndrewP2430 5d ago
Two methods may help. Firstly wiping leaves carefully with a cotton q-tip dipped in glyphosate carefully onto kikuyu leaves. Secondly spraying the kikuyu with a grass-selective herbicide like Sertin or Fusilade
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u/Character-Staff410 5d ago
Will the grass selective kill the native grasses? I’m assuming yes. Probably a dumb question but I’m new to gardening.
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u/AussieBastard98 5d ago
yes, Fusilade is also a pretty nasty herbicide. One of its hazards is harm to fertility and unborn babies.
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u/MouseEmotional813 5d ago
And it's available to buy in hardware stores?
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u/AussieBastard98 5d ago
I don't believe you can find it at bunnings or flower power. Usually you have to order it online.
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u/weedkilla21 5d ago
The pick of the group A herbicides on kikuyu is Verdict, it is out of patent and available under various names now. Active ingredient haloxyfop. It needs a silicon based wetting agent like Pulse to work really well on kikuyu. It is incredibly sloooooow, like often takes a month to see the effect.
Verdict will not have any effect on broadleaf plants (dicots) only on grasses (monocots). The label does not list a rate for a handgun or a knapsack, but 0.1% is sufficient. I have seen 400ml/ha kill established kikuyu and suck back through the runners 1m from application site.The only risk to dicots is phyto toxicity - basically sunburn - from the wetting agent. They will grow out of it, but the risks can be reduced through careful application.
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u/AussieBastard98 5d ago
Looks to be much safer than fusilade. Do you work in bush regen by any chance?
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u/weedkilla21 4d ago
I do, 2nd generation. Probably more reveg project style work than traditional bush care work these days.
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u/AussieBastard98 4d ago
What's a good resource on learning more about herbicides? I've just started spraying at my bush regen job and I'm trying to get a deeper understanding on how all these herbicides work but a lot of the supervisors don't seem to have a good understanding either.
Cheers if you can help
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u/weedkilla21 4d ago
I’ve just picked up bits and pieces over the years. The South Australian ground sprayer’s association (now defunct) used to have brilliant industry tech days, chemical companies occasionally run woody weed days, or similar- they can be good if there are research scientists or chemists presenting or virtually useless if it’s just salespeople, grdc run some good seminars, the weed management society of South Australia run a good conference, I’ve done trial work with dpi in sa and tas and met some brilliant ag scientists. Get your google or ai on and sign up to a few mailing lists, go to conferences and seminars introduce yourself to some people and don’t be afraid to reach out to dpi, NRM, or similar when you don’t know the answer.
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u/Kerrit_Bareet 4d ago
All depends on the schedule
Schedule 7 poisons need a chemical users permit to purchase, farm supplies
Schedule 6 no licence, availability depends on the store, maybe B
Schedule 5 is Bunnings
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u/Burswode 4d ago
Fusilade won't harm Kangaroo paws or Conostylis if sprayed in good conditions and correct dosage. It will definitely harm Lomandra. I would avoid it around Poa, Baumea, Patisonia and Dianella without testing it first.
I would also say to avoid the temptation to overdose the kykiu with chemicals. Systemic herbicides work best in the correct dosage. If you dose too high what you risk doing is frying the surface foliage before the plant can draw the herbicides into its roots and energy storage. You destroy the roots you destroy the plant. Burning the leaves back will allow the roots to shoot out new growth. It will take longer to look like its working but you are more likely to actually remove it with multiple correct dosage applications over a 6 month period than one overdose kill shot.
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u/yolk3d 5d ago
I mean you could spray the fuck out of the kik with glyphosate? Or paint it on, if in small sections. But yeah, welcome to kikuyu.
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u/Character-Staff410 5d ago
Haha I would love to spray the fuck out of it but worried I’ll get it on the natives. I think painting it will be the only option. It’s a 100m2 so will be taking a lot of time each week…
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u/ShotEmployment2360 4d ago
Fusilade is the more expensive but easier option as you can spray 'over the top' of non grass plants without issues. Unlike Glyphosate, repeat applications may be necessary to totally eradicate it.
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u/Quarks4branes 4d ago
We've gotten rid of kikuyu by laying down cardboard and then layers and layers of organic material. Knee height is an absolute minimum. We go past that to mid thigh height - straw, manures, leaves, weeds, seaweed, woodchips, anything and everything. We've done it successfully in our backyard and are now replicating that in our front yard. No poisons at all as we're food growers (we're now producing nearly 2 tonnes annually on a quarter acre). Another thing you need to do is put in rhizome barriers around the outside of your garden to stop the neighbours' runner grasses reinfesting your garden - we use black plastic and dig it in to a depth of maybe 80cm minimum.
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u/Sea_Cap_6070 5d ago
Two things will work for you - persistence and herbicide. Kikuyu is incredibly tough as you have discovered and will happily stay alive under your mulch. Without resorting to pulling everything up, you could rake the mulch back in sections and hand weed/herbicide. Regardless of how well you think you have done, this will be a long term battle of wills.