Germination ecology of winter annual grasses in Mediterranean climates: Applications for soil cover in olive groves

•Mediterranean woody crops are seriously threatened by soil erosion.•Seeding native grasses for ground cover is urgently needed.•We studied germination timing of six grasses in response to temperature and moisture.•Studied populations are not dormant and show differences with temperate regions.•The study species are adapted to Mediterranean climates and are suitable for ground cover.