Hillingdon SuDS Design & Evaluation Guide

9.10.2 The Principles of SuDS planting selection & design
SuDS vegetation choice and design should
achieve the following:
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General planting design should connect
with the SuDS landscape, ideally with
grassland, woodland or ornamental
planting creating linkages for visual
benefit and biodiversity. The design
criteria set out in the Biodiversity section
(9.9) should be followed where
appropriate.
Vegetation should permanently cover the
ground, both in summer and winter, to
prevent erosion of the soil surface.
The matrix of roots, stems and leaves of
vegetation slows the flow of runoff,
filtering water and encouraging silt to
settle out in components like filter strips,
swales and basins.
SuDS planting is often naturalistic in
character, particularly where SuDS are being
applied to a greenfield site. Naturalistic
planting is usually the most appropriate,
providing maximum biodiversity benefits as
well as being cost effective, resilient and
most likely to have modest long term
maintenance requirements.
In built up areas a more formal and
ornamental design style may be required for
raingardens, bio-retention features and green
/ blue roof surfaces. Recent research by the
Royal Horticultural Society (RHS) has
demonstrated that ornamental plants, close
to the wild type, especially from the northern
hemisphere can provide similar benefits to
wildlife as native planting but the capital cost
and management can be more difficult and
expensive.
Detailed Design
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A vigorous growth of vegetation,
particularly when forming an extensive
Contract arrangements should always allow
for additional or remedial works to ensure the
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root mat, encourages natural losses into
integrity of vegetation surfaces that perform
the ground throughout rainfall events.
a SuDS function.
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Planting design should avoid fertilizer,
pesticides or herbicides wherever possible
to avoid leaching of chemicals into the
SuDS and groundwater. They should use
careful plant selection and a soil
conditioner such as ‘green waste
compost’ as an alternative to suppress
weed growth and improve soil fertility.
Strutts Centre, Belper.
Brick channels collect roofwater for linear
raingarden with garden style planting.
London Borough of Hillingdon SuDS D & E Guide
© 2018 McCloy Consulting & Robert Bray Associates