Annual meadow grass on sports grounds, we look at the problem of poa and offers some solutions/management techniques to managing this evasive weed grass. Poa is known to many as a weed grass and the definition of a weed is, just a plant growing in the wrong place i.e., on our sports grounds.
There are a few types of poa including smooth stalked meadow grass, just to clarify and we are solely talking about Poa annua (annual meadow grass).
What grasses do we want then?
Generally speaking for winter sports and cricket perennial ryegrass is the desired grass species we need to overseed with and help it flourish. Rye has a higher wear tolerance, recovers from play quicker along with a few other benefits.
Why is Poa such an issue?
-Fills in where gaps appear in the turf, helping to maintain grass cover.
-Some sports specifically golf, have learnt to live with it (not all clubs) but much less desirable for winter pitches and cricket squares, for the below reasons.
-It’s shallow rooted, this means it will have high watering requirements.
-Low wear tolerance, as it is shallow rooted so kicks out easily as only provides a shallow anchor to keep the plant in the soil.
-Crowny growth habit and when grass is thinned out for cricket wickets it creates an unevenly grassed surface which has effect pitch performance at its worse. This is in comparison to the more upright and desirable rye grass we all use.
-Poa stems and roots are known to be thatch forming, in comparison to more desirable grasses.
-If allowed to build poa is more prone to disease. Poa creates a thatch layer and in turn thatch leads to a surface that can hold moisture/water.
-Invasive by nature and hard to manage once it is established.
How does Poa get in the surface?
–Seed blown in on the wind!
-Contained within bird droppings?
-By foot or even machinery movement i.e., on tyres or rollers.
-Via bare soil and worm casts.
-Unsterilised sports top dressing materials.
Management of Poa Options
When l say prevention, these are all tools and it’s very hard to maintain an environment, to keep poa out completely.
-Higher/high seed rates.
-A thickly maintained grass cover, with little room for poa to self-seed into.
-Verticutting (possible bi weekly) during periods of growth, encouraging a tight, dense grass cover not allowing poa in.
-Avoid over watering (poa likes wet conditions) to prevent the encouragement of any poa that may be in the sward. Equally shallow watering also suits the shallow rooted poa, so balanced well throughout watering is the key.
-Use of growth regulators, to manage/slow seed head formation.
-Overseeding during the season is key, if we don’t get our desired grass into those spaces, poa will more than likely find its way in and is less fussy, it will invade bare/ warn areas very quickly.
-Renovations periods, aggressive removal of this stalky grass with high seed rates of your desired species to out compete the poa.
-Collection of clippings/seed head especially during poa flowering periods.
-End of season renovations, especially hard scarification followed by high seed rates.
-Top-end football clubs often koro (plane) off the top of the pitch and with poa being shallow rooted this removes the plant, then they reseed with the desired grass species rye.
-In cricket we also have the option to koro or fraise. Fraise mowing removes the shallow poa grass only, leaving behind the desirable rye grass species.
Koro-Removes all living grass plants and soil, in a planning action.
Fraise mowing, leave the deeper-rooted grass plants intact, but clears out the top of the grass canopy of litter/thatch.
Annual meadow grass on sports ground
Annual meadow grass on sports ground- What is verticutting?
Verticutting is a vertical cutting action, similar to scarification but just usually closer spaced blades, thinner and light in aggression when compared to scarification. Verticutting is designed to just work in the top of the grass canopy and not impacting the soil, whereas scarification blades are designed to work in and below the soil.
Regular verticutting, helps remove litter (dead grass leaves etc) and helps train the grass plant to stand vertically and also helps remove clumpy grass such as poa, along with its seed heads.
Options for grassroots clubs without access to a pedestrian verticutting machine!
–The use of drag brushes/matt or harrow anything to keep the plant upright, poa doesn’t like being pushed around and as crowny in nature, this will go against its natural growth habit.
-Probably best avoid keeping the poa upright when its seeding, if not collecting the clippings/seedheads or this will just spread the seed heads onto and into the sward.
-Small areas, you could use a garden rake or a lawnman to keep the grass upright, this will encourage your more desirable grasses and present the poa seed head, for when you do cut and collect.
-Don’t under water as shallow watering will encourage the poa, over the desirable ryegrass. One or two big waters is better than little and often watering. This is hard as poa is shallowed rooted so cries out for water pretty quickly, so we reach for the water and thus we encourage this shallow rooted foe.
Low water pressures is a major challenge to many clubs here, but also the lack of watering may also assist in the starving out of the drought prone poa.
-End of season renovations (cricket specifically), invest (hire) in a decent scarifier that can really get at the poa, its hates being cut vertically, hit it in a few directions. Invest in a higher seed rate over 50 grams a square metre and 70 grams is around what l d use, in the aim to outcompete the poa plant.
You can kill a square/pitch with kindest, poa leads to thatch, thatch leads to dead wickets and water holding surfaces.
Can we win the battle poa vs our desirable grass species?
Speaking from my point of view working within county cricket, if it’s on your outfield its more than likely going to find its self the square. This is where end of season renovation comes in, aggressive scarification and high seed rates 50/70 grams.
In season bi-weekly verticutting (if growing vigorously) and then overseeding in season, all help to keep poa down to a low percentages of total grass coverage. We also have funds to koro/fraise mow off every 3-5 years and start/seed afresh desired grass species.
Clubs– As with the county cricket, if you can’t keep it out of your outfield (unlikely) it’s likely to be on the square, so verticut when you can within your limited time. Invest in a thorough end of season renovations and high seed rates and be realistic, you are going to have some poa but do what you can to keep the percentage manageable.
Club also have the option to koro/fraise mow it’s not cheap but once every five years it maybe a suitable consideration. Seek independent advice before considering such works.
Don’t beat yourself up in regards to poa.
Annual meadow grass on sports ground- Winter Sports
At the top-end clubs can just koro (plane off) but at the more realistic end of sport depending on your resources, there are the options of harrowing and maybe for a few verticutting and then thorough end of season renovations.
Aeration and topdressing will also all help counter the effects of the thatch forming plant and again all, it’s all about keeping the percentage of poa annual? down and manageable.
Grassroots clubs- limited equipment or and non?
Even if full end of season renovations isn’t possible, just prioritise to the high wear areas and get down a desirable seed, rather than allowing the poa weed grass to invade. The poa might help fills in some bare areas, but as shallow rooted it will probably be the first to divot out.
“For most of us it’s an ongoing battle, rather than a one-time battle we can win so put in as many control management techniques as you can, but also be realistic if you think there’s a quick win”Tweet
Community thoughts-Over to you?
In my experience there are no experts, we are only as good as our current knowledge and there’s always more to learn, so as l say these are just some of my thoughts and experiences, what’s yours?
Annual Meadow Grass on Sports Grounds, by Brian on behalf of the TurfCareBlog Community.
If you wanted a bit more information on verticutting and fraise mowing, check out this blog-https://turfcareblog.com/how-to-control-and-prevent-annual-meadow-grass/