The 2 images attached show what I'm up against and I'd say for the first 20 years of looking after the lawns I tried a variety of chemicals to hold back the onslaught of Poa. As many attest, the usually chosen method is to grab a screwdriver and a bucket and hope you don't spill any seeds in the process. The issue can be those seeds can germinate up to 7 years later, so honestly you will never win the battle.
I'm happy to report that I feel I am winning the war on weeds and neighbours through a change of mindset. What if there was a product that worked on stopping the seeds from germinating in the first instance? Well, enter the word "pre-emergent" to the discussion. After much research and internet searching I singled out an active ingredient called PRODIAMINE as the one to work for me. The brick wall I came up against was that local distributors all believe we have acres of land and therefore the need for litres of their product and the poor householder either paid for a lifetime supply of product or went back to the screwdriver and bucket. For reference, at the time a 1L bottle of 18% strength was around $400 to $900. Today Barricade can be bought for about $200 for a 1L at 48% strength. A 10 second search will reveal alternate brands of 2.5kg @ 65% strength around the same price..
I then jumped on eBay USA and looked around... I saw Prodiamine available and enquired with the seller if they had shipped to AU before. With confirmation received, I bought a 2.5kg container (granules) at 65% strength for about $120 and received it with 10 days. Instructions state to use 12g (1Tbs) per 100sqm of lawns, and by my maths that is like 43 years worth of product, if I kept it all to myself. It has been shared a few times and from this year I'll plan a few sneaky sprays into the neighbours area too..
Since using this product I'm unlucky if I see 2 or 3 sprigs of Poa per year!! You don't even need a screwdriver for that as they just pull up with zero effort. I had an intrusion of crab grass 2 years ago and this stuff stopped that coming back too... It would be one of the best items I have spent cash on, not to mention the time saved. Broadleaf still crop up from time to time but I'm finding them to be weak or thin and pull up easily and I find a product called "Buffalo" from www.specialistsales.com.au works much better than Dicamba based products..
My experience with post-emergent treatment for Poa has 2 options. First if the seed heads have NOT arrived, then Bunnings etc have the Winter Grass Killer off the shelf and it worked well. Second, if the heads have appeared the only active ingredient I have found to work is PROPYZAMIDE - used in a product called Poa Pro at 50% strength or David Walker's at around 10% (by memory). Water in well and even if showing signs of working apply again and water in well. You can try and time a late Summer application and if you're lucky you'll minimise new intruders.
The more I learn about lawn care, the more I lean towards putting less "negative" stresses on it. Post emergent is a negative (killing) agent and the surrounding area has to be better off if not subjected to it. 3 applications per year of pre-emergent is less chemical than the regular/constant spraying of post-emergent. Also, concentrating on nurturing the turf AND the soil to produce a better/stronger outcome will naturally help ward off weeds.
