Annual meadow grass, the nightmare of every greenkeeper and field manager

Annual meadow grass (Poa annua) is one of the most common grass species. It is an annual, sometimes biennial and occasionally perennial meadow grass (Poa) with shallow roots. Annual meadow grass flowers at an early stage, and its height does not exceed 25-30 cm. However, this plant will usually remain much shorter.

Keep overseeding with SOS right through the winter, if possible! If this is done regularly, there will always be always germinating seed in the soil.

Erwin Beltman
Field manager Feyenoord Stadium

How to recognise annual meadow grass

Annual meadow grass is usually easy to identify. The youngest leaf will appear in a folded shape. There are no auricles at the base of the leaf, and the underside of the unribbed leaf is matte and often pale green in colour. This colour difference is often clearly visible in a field. Furthermore, Poa annua has a long and milky-white ligule. In a field, annual meadow grass can easily be identified by its abundant seed formation. After all, it flowers year-round. The leaves are unribbed, which means that they are soft and wavy.

 

Low wear tolerance

The wear tolerance of annual meadow grass is moderate to low, partly for reason of its shallow roots. This means that the grass is easily kicked or hit away, which may result in many bare spots that will significantly reduce the quality of play on a sports field or golf course. In addition, annual meadow grass has an unattractive appearance.

Appearance of annual meadow grass

The appearance of annual meadow grass is unattractive. Poor nutrition will change its mid-green colour to a lighter green. The colour will change in dry conditions and when there is insufficient moisture in the top layer, annual meadow grass will immediately turn light green and then begin to flower profusely.

 

Early germination

Annual meadow grass germinates at soil temperatures as low as 7 - 8 °C. When the fields have been played bare, annual meadow grass will often be the first to appear as most grass mixtures germinate at higher temperatures. This means that the bare patches are filled in fast and the good thing is that there is a green field, which is always better than nothing. However, this benefit does not outweigh the disadvantages. Annual meadow grass can be tackled by, for example, SOS from Barenbrug. SOS germinates at approx. 6 °C, which means that it is virtually impossible for annual meadow grass to establish itself.

SOS - Super Over Seeding

Another solution is SOS. This is an excellent product, especially in the winter months as it germinates at a temperature as low as 6 °C. This is sooner than annual meadow grass, which germinates at around 8 °C. SOS is therefore another serious challenger of annual meadow grass. 

Not sustainable

In recent years, sustainable control of grass has increased significantly in importance. Annual meadow grass needs large quantities of water and fertiliser. Sustainable grass management is not possible with annual meadow grass. Environmental damage is therefore the result of this grass plant.

 

A major stress factor for annual meadow grass is drought. Its reaction to drought is to flower profusely, and all these flowering tufts don’t do much for the visual appeal of the field. Stress factors cause annual meadow grass to reproduce. It will try to maintain itself by forming seed heads. When this happens a lot, there is no stopping annual meadow grass and it will appear everywhere.

 

Annual meadow grass is very sensitive to diseases. Fusarium and Dollar Spot are the most occurring diseases in fields that contain annual meadow grass. These diseases can seriously damage a field.

I overseeded with SOS in December and counted the GDDs. Fourteen days later, the SOS plants were already coming up. Fantastic!

Henry de Weerd
Groundsman, FC Twente, Enschede

Tolerates close mowing

Annual meadow grass can flower even at a mowing height of 0.5 cm or lower and deliver germinable seed, and several times a year! Many grasses do not survive close mowing, but annual meadow grass does.

 

Thatch build-up

Naturally, extended rainfall leads to the formation of a wet top layer. A wet top layer is more sensitive to compaction than a dry one. Wet conditions hinder the decomposition of dead stalks and roots, and this results in a thick thatched, matted layer. There is now a situation in which annual meadow grass can grow with ease because of its shallow roots. The thatch prevents water from reaching the unsaturated areas, which in turn may lead to water problems.

RPR’s fast germination is really fantastic. It means that there’s virtually no risk of annual meadow grass establishing, and we end up with a sward of the very best quality in our entire pitch.

Theo van Benthum, field manager
Het Goffertstadion - NEC, Nijmegen (NL)

RPR

Most grass mixtures lose the battle against annual meadow grass. This is due to the very fast germination of annual meadow grass. It germinates and establishes itself faster than most grass mixtures. However, at Barenbrug we have mixtures that are even faster. 

Nightmare of the greenkeeper and field manager

Annual meadow grass will fill in a field very quickly, and it is green. However, this is the only benefit annual meadow grass provides and it certainly does not outweigh all the aforementioned disadvantages. Annual meadow grass, with all its negative consequences, can cause the greenkeeper and field manager many sleepless nights.

 

If you would like more information about the options and solutions regarding annual meadow grass on sports fields, click here.

 

For information about annual meadow grass on golf courses, click here.

Annual meadow grass
Poa annua is an annual, sometimes biennial and occasionally perennial meadow grass (Poa) with shallow roots. If no action is taken, it will spread everywhere. This may lead to many bare patches and various diseases.
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