Hogsmill River transformed into wetland

Volunteers turned out in force to see the culmination of the Hogsmill habitat improvement project at the Knights Park campus, Kingston University.  The project is a collaboration between Kingston University and South East Rivers Trust.  The Kingston University Biodiversity Action Group works within the University campuses and local area with the aims of improving green spaces for both wildlife and people.  


The task was to plant up the new riverbank areas with marginal plants ready to take advantage of the spring warmth. Following earlier preparatory work, signs of silting up and diatom growth in the brash and gravels were appearing – a sign there are plenty of nutrients in the water. 1000 plants were planted amongst the brash and gravel, all typical marginal species native to Britain: marsh marigold, fool’s watercress, water mint, watercress, greater and lesser sedge, flag iris and bur reed.

  • Marsh Marigold (Caltha palustris) is a member of the buttercup family which flowers between March and June. We even had one or two flowers on the ones we put in which gave a very welcome injection of colour.
  • Water mint (Mentha aquatica) grows with creeping runners which is good news for colonising our new riverbank. A plant of multiple benefits as the leaves can be used similarly to other mints and the flowers are attractive to bees too.
  • Branched Bur Reed (Sparganium Erectum) will provide an important habitat for wildfowl nesting, roosting and feeding once established. To help it on its way we ensured it was planted in the slower flowing, shallower to avoid submergence and dislodging.


But planting these in flowing water, albeit slowed by the brash and gravels, was a test of skill to get them the right height to avoid those sensitive plants being submerged and others floating away altogether! Gauging the correct depth was an unenviable task, as the river levels here at the Hogsmill vary quickly and frequently. By the time the full project is finished, many plants may need to be repositioned as the water levels will change over time.


To give the plants the best start possible, rootballs were wrapped in hessian tied with twine then given an additional scoop or two of clay soil to supplement the soil they came with.  A chicken wire fence erected to protect the young plants from waterfowl and an orange mesh fence along the bottom of the wall to catch windblown litter. As the riverbank planting establishes the need for these will lessen and they will be removed to let nature take its course.

Interpretation signs were introduced to explain what has been done so campus users can understand the improvements and to highlight the benefits for wildlife. Hopefully in months and years to come, we will see a wide age-range of fish making use of the new conditions, more birds and bats taking advantage of the wealth of invertebrates it should support, and a visual feast of pretty flowers and grasses on the riverside.



  1. Pingback: Hogsmill River transformed into wetland – revisited | Landscape Interface Studio
  2. Pingback: London Rivers Week: Hogsmill River restoration | Landscape Interface Studio

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