Blackgrass is generally very visible in crops at the end of May and in the month of June.

However, it should be controlled by this time. It is generally still green in May and turns black in June.

If it is new to your farm, then June will likely be the first time you will see it. If you do, that is the time to take action and remove it before it goes to seed.

Key things to identify blackgrass

  • It is purple at the base.
  • Early leaf blade twist is clockwise.
  • Blackgrass does not have any hairs on the leaf or the stem.
  • Jagged ligule (membrane flap behind the stem, where the leaf meets the stem).
  • No auricles around the stem, where the leaf reaches the stem.
  • Slender, long plant.
  • Seed anthers (flowering parts in May).
  • Green in May, turns purple/black in June (going to seed shed at this time, needs to be controlled).

    • What to do if you find blackgrass in your field

  • Put a plastic bag over the plant. Don’t allow it to shed as you pull it.
  • If there is too much to rogue, spray it with glyphosate.
  • It is possible to make wholecrop silage when the blackgrass is still green before changing colour and going to seed.
  • You could also strim or top the area where the blackgrass is before it goes to seed.
  • If the field is whole cropped or topped, then spray it with glyphosate once it starts to regrow.
  • Don’t allow slurry from animals that consume it back on to tillage land.
  • Clean machinery before leaving a contaminated field.

    • What to do with a field with blackgrass

  • If the field is in minimum-tillage, then you should plough the field.
  • Rotational ploughing (one year in five) can bury the seed until it becomes unviable.
  • Use shallow cultivation to create a stale seedbed between crops.
  • Delay drilling in autumn from peak germination period.

    • Here are the parts of the plant you need to check.

  • Increase seed rate for better crop competition.
  • Plant a spring crop if you can.
  • Plant a break crop that offers control of grass weeds like oilseed rape or beans.
  • Monitor the field and pull any blackgrass plants that reemerge.
  • You may need to spray patches of the crop in the following years as well.
  • Remember, blackgrass is now a noxious weed, so you are obliged to control it and can be told by authorities to get it under control.