Plant Communities at Silvertown & Open Mosaic Habitat

The Silvertown site was originally constructed as docks for ship-repair and more recently, for flour processing. The site has been left derelict for several decades until now, and large parts of this post-industrial site are categorised as ‘Open Mosaic Habitat on Previously Developed Land’ or OMH. OMH is found on post-industrial or brownfield sites where a unique mosaic of environmental conditions supports an extraordinary range of scarce invertebrate species.  It is recognised as a ‘Habitat of Principle importance’ in the UK and Buglife have referred to OMH as the “Rainforests of the UK”.

“While often seen as degraded they can provide unique environmental conditions that support rare and threatened invertebrate assemblages found nowhere else. Their history, alongside thin, low nutrient soils can allow flowering plants to thrive, as normally fast growing and dominant species cannot get a foothold, benefiting pollinators with a wealth of nectar and pollen sources.” Buglife

The strategy at Silvertown is to recreate OMH. This is quite unique as this is an unusual landscape type to recreate in the context of an urban mixed-use residential development. As such the new planting may look a little different to typical urban development - it is wilder and more naturalistic. You can find similar examples of this type of plantings at Knepp Rewilding Walled Garden in Horsham and Potters Fields Park near Tower Bridge in London.

The aim has been to recreate a range of OMH proxy habitats starting with low fertility soils (or substrates) such as sands, crushed concrete and brick, and gravels. These ‘stressy’ substrates are suitable to certain plant species and critically this helps to slow the process of natural succession from bare ground into grassland, then scrub, and finally woodland that occurs with a richer soil resource.  The substrates therefore maintain high plant diversity and create conditions suitable for ground nesting invertebrates.

We try to use locally sourced recycled substrates where possible to reduce use of virgin materials and reduce carbon emissions. We have experimented with the use of a chalk-like by-product that is used to filter sugar at the nearby Tate & Lyle factory.

The proposed plant species are a mix of native and non-native wildflowers and small shrubs commonly found in OMH and analogous communities and have been carefully selected to suit the site conditions and for their resilience to a changing climate. The proposed plant mixes have been composed to flower across a long period during the year, from early spring to late autumn, to maximise seasonal colour and provide pollen and nectar forage.

Various features will provide valuable habitat for invertebrates; sand lenses for ground nesting bees, log piles for beetles and drilled wooden posts for solitary bees. Ephemeral water features collect water for birds and invertebrates to drink from and create localised variation in the microclimate.

New Plant Communities found at Silvertown:

SuDS Rain Gardens
Rain Garden planters are located along road edges and provide sustainable urban drainage by collecting rain water from adjoining roads and footpaths. This helps to mitigate urban flooding by slowing the flow of storm water into sewers, and improves water quality downstream. The Rain Gardens are richly planted with planting that is tolerant of wet and dry cycles.

Low Fertility OMH
Planted mounds of sand and crushed concrete substrate, these topographies have varied aspects, moisture and light gradients. South facing slopes are excellent for ground nesting solitary bees, whereas north facing slopes will be shaded and humid encouraging mosses and lichens. Crevice features formed with reclaimed concrete from the site creates specific habitat for drought tolerant alpine type plants. Plant mixes are highly biodiverse and drought tolerant.

Green Pavements
These open jointed green pavements replicate the fringe plant communities that are found in cracks in pavings on OMH sites and support a range of low growing stress tolerant plants.

The ground planting has been planted using small potted perennial and shrub plants to reduce carbon emissions involved in transportation. This will start to flower in 2026 and will reach full size next year.