How do I control Poa in my lawn?
I want to control some Annual bluegrass which I think is what you call Poa? It’s a NZLA dark rye lawn.
Am I correct that I should do 2 applications using Etho? I’m also thinking about putting down some Blockade heading in to winter is this a good idea?
Hi Toni, that’s correct.
You’re looking at two applications 14 days apart.
The first application should be watered in. This helps create a pre-emergent barrier, which stops new seeds from germinating. It’s also taken up through the roots, so it will start weakening the plant, but the main job at this stage is preventing further seed germination.
The second application goes down 7 to 14 days later and is left on the leaf. That’s when it really starts working properly on exisiting Poa.
Just keep in mind Etho is not a fast herbicide. It works by causing growth abnormalities in the plant, which stresses it over time until it dies. A lot of people expect quick results. Realistically, you’re looking at around 3 to 4 weeks from that second application before you start seeing results.
On your second question around Blockade, in New Zealand it sits in a bit of a grey area on cool season lawns. It’s not labelled here for that use, so it can’t officially be recommended on the label. That said, if you look at overseas labels, including the US, Prodiamine (the active) is labelled for cool season grasses. Unfortunately in NZ it's only labelled for warm-season turf. This is due to the company that first registered the chemical in NZ.
In practice, it is safe on perennial ryegrass and widely used that way in the US.
Blockade will give you up to 6 months of pre-emergent control, stopping new weed and grass seeds from germinating. Just be aware of the trade-off. If you apply it now, you won’t be able to overseed in spring because it will stop lawn seed from germinating as well. You’d have to wait 6 months before any over-seeding.
If you’re happy with the current condition of your lawn and don’t need to seed, it’s a very effective option for preventing new Poa and other weeds coming through.
Blockade will not kill anything already established with a root system. It only works on new germination by stopping root development in emerging seedlings.
@Jonny Hicks thanks for the speedy and detailed reply!