As the drive to increase biodiversity and pollinator species continues, it seems that some seed mixtures contain far more than colourful flowers.
The highly invasive blackgrass weed has been found in a commercial wildflower mixture that was sown as an experimental plot in Teagasc’s crop research farm at Oak Park in Carlow.
Such mixtures have been planted in farms, schools, gardens and amenity areas, so if blackgrass contamination is widespread, it poses a huge risk of contamination to tillage land and to the Irish tillage industry.
Blackgrass can be described as worse than foot-and-mouth disease for tillage because it moves about very easily and seeds can remain in the soil for many years.
A commercial mix of diverse wildflowers and grasses was planted at Oak Park on one field margin last autumn to examine its impact.
But in recent days, farm manager John Hogan noticed that it was contaminated with blackgrass.
As this was beginning to flower, the margin had to be destroyed to prevent the spread of blackgrass seeds into the field and neighbouring crops.
John Spink of Teagasc commented that if wildflower seed is imported from or originated in Britain, there is an added risk that the blackgrass seeds could be resistant to herbicides, thus adding to the threat.
Blackgrass is already resistant to a wide range of herbicides in Britain.
Teagasc’s Michael Hennessy is worried that similar contamination issues elsewhere could go unnoticed as wildflower mixes are frequently used in domestic and amenity situations.
He asks that anyone with such seed mixtures inspect them and looks for grasses with long slender seed heads.
It is critical that they be removed before seeds are formed.
Wildflower seeds are not currently covered by the certification system and blackgrass is still not listed as either a noxious or an invasive weed.