Weed control is the most common problem to be addressed and often depends on proper seeding. Of course, the weed pressure of the plot in the past also has a major influence.
In addition, perennial field margins should also be mowed annually with removal of the clippings. This is necessary to get light to the bottom so the seeds can germinate again. Mowing can be done in autumn after the last flowering, usually from the end of September onward. However, you can also choose to wait until February, so that the border acts as a shelter for wildlife and a wintering place for insects. Do not mow too deeply (about 0.2 metres above ground level), so that the rosette of the plant remains intact.
In the Dutch rapport 'FAB and field margins' (Dutch) you can find more information about management of the field margins.