Chalk river plants
The water plants growing in most chalk rivers are characterised by water-crowfoot, water-starwort and lesser water-parsnip; which dominate in spring and early summer. As summer progresses, watercress and water forget-me-not encroach from the margins.
To grow healthily, water-crowfoot needs clean, swift-flowing water and silt-free gravels. It became less common in the dry years of the mid-1990s. However, in the last five years river flows have increased, and it is now returning on many rivers.
The spread of non-native invasive plants such as Japanese knotweed, giant hogweed and Himalayan balsam is an increasing threat to native bankside plants. Local attempts to eradicate them have had limited success.
