Competence for a green infrastructure plan

A green infrastructure plan is normally owned by a landscape architect, with an ecologist supplying the habitat content and a drainage engineer checking anything that holds water. No statute says who may write one, which is why the question of who writes a green infrastructure plan gets answered badly on small schemes: the drawing is produced by whoever has the planting symbols in their library, and the thirty-year management section is left to a paragraph of good intentions.

Councils rarely refuse a scheme because the plan was written by the wrong person. They do refuse, or condition heavily, when the plan cannot be built, cannot be maintained, or contradicts the ecology report sitting next to it in the same submission.

What the plan has to set out

A Green Infrastructure Plan answers four questions for a case officer. What green and blue features the scheme provides, where they sit in relation to buildings and routes, what they are expected to deliver for people and wildlife, and who looks after them once the contractor leaves.

That means a plan drawing, a schedule of features, a planting specification and a management and maintenance programme with periods and responsibilities. On a larger site it also means a connectivity narrative, because green infrastructure is about the network rather than the individual tree pit, and a feature that links nothing has a weak case.

The document sits above a Landscape Strategy in scope while overlapping with it heavily. Where both are required, settle early which one carries the management schedule, or you will submit two different maintenance regimes for the same shrub bed.

Landscape and ecology input compared

The division of labour is reasonably stable in practice.

A chartered landscape architect, usually a member of the Landscape Institute, handles spatial design, levels, surfacing, tree positions, visual structure and the relationship between planting and buildings. An ecologist with CIEEM membership handles habitat type selection, the condition targets that the biodiversity metric relies on, protected species constraints and any seasonal restriction on clearance.

Those two sets of judgements collide more often than people expect. A landscape architect may want a mown lawn with specimen trees where the ecologist needs a species-rich grassland cut twice a year, and the metric assumes the latter. If the plan shows one and the biodiversity gain plan assumes the other, the authority has a genuine inconsistency to point at.

The practical fix is to name the author of each section and date it, which is also good discipline for every other report in the pack. We cover that in more detail in why a planning report needs a named author and date.

Species selection and establishment competence

Species selection is where inexperience shows fastest. A planting schedule needs to survive the site it is drawn on, not the site the designer would prefer.

The judgements that need real experience are soil and drainage tolerance, exposure, salt and pollution tolerance on street frontages, mature spread against building lines and sight lines, biosecurity and provenance, and the match between nursery stock size and the establishment regime available. Standards exist for most of this. BS 8545 covers the sequence from nursery to independence for trees, and BS 42020 sets out how biodiversity information should be presented in planning submissions.

And then there is pest and disease risk, which has moved fast enough over the past decade that a schedule copied from a 2015 project is a liability. Ash, elm, horse chestnut and oak all carry constraints a competent author will know without being told.

Establishment is the stage that fails. Irrigation for the first three growing seasons, formative pruning, weed control around the root plate, staking and tie checks, and a replacement clause for losses are the things an authority will look for, and they belong in the plan rather than in a hope that the contractor remembers.

Maintenance and management planning

The management section is a thirty-year commitment on many schemes, because that is the period the biodiversity gain regime works to for habitat secured under the Environment Act 2021. Writing it needs someone who has priced grounds maintenance.

The content that carries weight is a feature-by-feature schedule with operations and frequencies, the first five years separated from the long-term regime, a named responsible body, a funding route, and monitoring with a trigger for remedial action. Vague commitments to maintain planting in perpetuity are unenforceable and officers know it.

Costing is a competence in itself. A management company service charge that has never been tested against a real maintenance quote tends to collapse in year four, and the planting goes with it.

Where the drainage engineer is needed

Anything that holds, conveys or infiltrates water needs engineering input rather than a landscape symbol alone. Raingardens, swales, filter strips, permeable paving, basins and tree pits that take road runoff all have a hydraulic function and a maintenance burden attached.

The engineer sets contributing areas, infiltration rates from site testing, media depths, underdrain arrangements, freeboard and ponding depth, and exceedance routes. The landscape architect sets levels, planting and appearance. Both have to agree the same long section, and a raingarden shown 300 mm deeper on the landscape drawing than on the drainage drawing is the sort of thing a lead local flood authority notices.

Where the drainage and landscape teams are in different firms, write down who owns the interface before planning submission rather than at technical approval stage. When two consultants disagree about the same feature, our note on what to do when the council's expert disagrees with your consultant sets out how that usually plays out.

Authority review and adoption of the plan

Review is split. A planning officer looks at layout, amenity and policy compliance. A tree officer or landscape officer checks species, sizes and spacing against local guidance. An ecology adviser, often shared between authorities, checks habitat types and the management regime against the biodiversity gain plan. A lead local flood authority officer checks anything hydraulic.

Four reviewers means four chances for an inconsistency to surface. It also means the plan is usually secured by condition rather than approved as submitted, with a requirement to submit a final landscape and management scheme before a trigger point such as first occupation.

Read the condition wording carefully when it arrives. A condition requiring a management plan for a period of thirty years from first occupation is a different commitment from one requiring five years of establishment maintenance, and the two get confused regularly.

Keeping the plan deliverable after handover

The honest weakness of green infrastructure plans is the handover. A document written at planning stage, with a design team that disbands at technical design and a maintenance contractor appointed three years later, has to survive without its authors.

Three things make that survivable. Write the management schedule as an instruction to a contractor rather than as a planning argument. Keep the as-built plan updated so the maintenance company inherits something accurate. And set the monitoring trigger at a point where remedial planting is still possible, which generally means an inspection in the autumn after the second growing season rather than a report in year ten.

If you need a reviewer with the right background to check the plan before it goes in, the professional directory is the route to a sign-off from someone competent in the relevant discipline.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.