Annual Meadow Grass (Poa annua)
Arguably one of the most successful plant species on the planet. With its adaptability and ability to reproduce rapidly, annual meadow grass can be found growing throughout the temperate climate zones of the world. Widely known simply as ‘Poa’, it is also referred to as annual bluegrass in the USA. However, despite it being found in most turf surfaces, it is never used in seed mixtures and is widely considered an unwanted weed species. Poa can be found growing in golf greens, lawns, meadows and is the grass that you will find growing in the cracks in the middle of a motorway.
In the UK, Poa makes up the majority of the sward in inland golf greens. It is able to tolerate the low heights of cut on golf greens and is capable of producing very good putting surfaces. However the issue is that it is very prone to disease, specifically fusarium, which is becoming harder to control due to reduced access to chemicals. Also due to its shallow root system, it requires regular irrigation, which in turn encourages more disease. In general it is becoming a harder grass to manage resulting in more golf course managers to transition to more sustainable perennial species such as browntop bent and Chewing’s fescue and slender creeping red fescue.
Key Characteristics
- Low wear tolerance
- Thrives in moist, fertile conditions
- Very susceptible to diseases
- Produces lots of seeds which allow it to spread
- Will grow in almost any soil type and location
- Very poor tolerance of heat and drought
- Capable of surviving and becoming dominant in golf greens
An Unwanted Weed Species
Despite being widespread, Poa is regarded as a weed species due to it having no truly desirable traits. Given time it will naturally begin to appear in a turf sward and look unsightly with its tell-tale seed heads that appear mostly in the spring, but that can appear at any time of the year. Controlling it is difficult as its seed is widespread in the environment. The best means of control is preventions, simply by encouraging favourable conditions for the existing perennial grass species, for example removing shade, good airflow, free draining and appropriate fertilising.
Favoured Conditions
Annual meadow grass will thrive in conditions that are damp and nutrient rich, more so if the area is shaded. Grass swards in shaded areas are prone to thinning, in which case annual meadow grass is likely to seize the opportunity to invade and begin to colonise the area.
Where will you find annual meadow grass?
Cracks in the road:
If you have ever had to weed a patio or a block paved drive, the grass you would have been pulling out would invariably have been annual meadow grass. Its ability to spread and colonise by seed in unrivalled, so much so that it can be found growing in the cracks on the busiest motorways.
Lawns:
It is far to say that every lawn in the UK will have some annual meadow grass in it somewhere. Any weaknesses in the existing sward, such as thin areas or patches, present an opportunity for it to jump in and establish.
The Antarctic:
Annual meadow grass is a highly successful species, so much so that it is the only non-indigenous flowering plant species to have established a breeding population in Antarctica. Inadvertently spread to the continent by humans, it is a great example of how the species is able to spread and colonise new ground.
Golf Greens:
Widely found in golf greens throughout the UK, often being the dominant species on many greens. It thrives in moist, fertile conditions and is capable of tolerating very low heights of cut. However due to it being prone to disease, it can be a hard grass to manage.
Other Grass Seed Guides
Why not read some of our other grass seed guides and find out more interesting information, to find the right grass for you.
