This vegetation type is dominated by the ruderal hemicryptophytes Melilotus albus, M. officinalis or Echium vulgare. It occurs on shallow, well drained soils with high gravel content and low availability of nutrients. It can develop in natural habitats of gravelly or sandy alluvial deposits, but it is more common in anthropogenic habitats such as dumping sites, quarries, gravel or sand pits, road or railway banks or disturbed places around roads or construction sites. In the Czech Republic it occurs from the lowlands to submontane areas.