Annual Meadow Grass Knowledge Hub

Despite its name, in the UK annual meadow-grass exists as both an annual and short-lived perennial but in arable situations it is usually an annual plant. It germinates throughout the year, with the period of maximum emergence from April through to September, the latter being the optimum time, possibly due to more reliable soil moisture.

The minimum temperature for germination is 2–5˚C, optimising from around 7˚C, through to a high of 35˚C. Emergence also increases with increasing soil moisture (up to a maximum of 40% of field capacity. Dry conditions however delay emergence.

Once established, it forms either a loose or compact erect, tufted plant and will flower within 44–55 days of germination. Because it flowers and seeds throughout the year, both emerging and flowering plants can sometimes be seen in close proximity to each other.

Although annual meadow-grass flowers independently of day length, seed head production is at its maximum in May and June, with seeds becoming viable only 1-2 days following pollination is capable of producing large numbers of seeds; a single plant may produce up to 13,000 seeds or more under favourable circumstances.

Annual meadow-grass can be found in winter cereals from autumn onwards, frequently on the headland areas of fields. It is also a rapid coloniser of set-aside land. It does not thrive under drought or very acid conditions, or in soils low in phosphates.

ID Images – Annual meadow-grass

Also known as rough meadow-grass, this weed is essentially a perennial plant. When mature, it is loosely tufted and spreads by both creeping leafy stolons and seeds. It occurs in a wide variety of habitats, but is more commonly found in pastures, roadside verges, waste-ground, and field margins Nevertheless, when present in arable crops, plant for plant, it is more competitive than annual meadow-grass.

Flowering occurs mainly in June and seedshed is in August. The seed requires vernalisation to flower the following year. Seedlings emerging in the late spring are therefore unlikely to set viable seed.

In cereal crops, rough meadow-grass may produce between 1,000 and 14,000 seeds per plant, but in open situations it can produce twice this number. Reproduction from seed therefore is an important factor in the spread of this perennial grass.

Seeds germinate under a wide range of temperature and moisture conditions. Those emerging before the winter will have both more, and earlier, flower heads than those emerging during the winter or spring. As with annual meadow-grass, the germination of rough meadow-grass seeds is by light and low temperatures inhibit germination.

Rough meadow-grass tolerates shade, and grows best on moist, nutrient rich soils that are slightly acid to neutral. It can also be found on clay loam and chalky soils, and only occasionally on sandy soil types. As with annual meadow-grass, it is also sensitive to drought

Rough-stalked meadow grass ID Images

Although there are many effective chemical controls available for meadow-grass, aim to manage the population with cultural techniques first.

• Delaying autumn cultivation and drilling

Annual meadow-grass germination peaks in September and declines with falling temperatures. Drilling crops in October reduces the amount of meadow-grass needing in crop control putting less pressure on herbicides.

• Removes clumps after ploughing

Ensure any clumps of surviving grasses are killed before sowing the next crop. This is particularly important in the case for perennial rough-stalked meadow-grass, as these can form the basis of future weed infestations.

• Machine hygiene

Before moving from field to field, or storing the combine, clean any obvious concentrations of weed seeds and crop residue from within the combine. This will help to reduce the transference of weed and volunteer seeds from one field to another.

• Spring crops

Competitive spring crops can outcompete meadow-grass. However, rapid establishment and growth is essential to close the canopy on meadow-grass.

• Boundary strips

Including cultivated boundary strips around a field to prevent the encroachment of weeds, this needs to be a employed as a consistent strategy – not a one-off.

Annual and rough-stalked meadow-grass can be successfully controlled at pre-em and post-em timings with several commonly used herbicides. There are no known cases of herbicide resistance in UK meadow-grass populations.

Pre-em control

Liberator (flufenacet + diflufenican) is a good choice for meadow-grass control. Flufenacet has good activity against both target species, working in the root zone. Diflufenican works on the soil surface and has moderate activity against meadow-grasses. Prosulfocarb is another proven option for pre-em meadow-grass control in cereals. Pendimethalin is effective against annual meadow-grass but less so against rough-stalked.

In general, newer chemistry and large stacks needed to control difficult black-grass and Italian ryegrass populations are not necessary for meadow-grass control, good results can be achieved with a simple herbicide programme.

Post-em control

A properly applied pre-em is usually sufficient for meadow-grass control. A spring post-em is typically used because there was no time to apply an autumn pre-em due to bad weather, or the farmer / agronomist prefers using only a spring spray to tidy up broad-leaf weeds at the same time.

Othello (mesosulfuron + iodosulfuron + diflufenican) is the specialist product for meadow-grass control. It is a mesosulfuron-based product but has a lower active loading compared to Atlantis Star or Pacifica Plus which are for harder to control grass-weeds.

Apply Othello at 1l/ha until early tillering (GS23) of meadow-grass. Ensure there is active growth and aim to apply as soon as possible in the spring to target weeds at early growth stages. With suitable timing and application technique it will provide good meadow grass control and protect crop yield.

It also has good activity against common chickweed, mayweeds, common field speedwell, field pansy, common poppy, groundsel, red deadnettle, shepherd’s purse, charlock and volunteer oilseed rape.  Also, cleavers are moderately susceptible. Meaning that it can tidy up many weed problems with one hit in spring.