Biosecurity conditions on landscape and planting schemes

A biosecurity planting condition asks you to prove where your trees and shrubs came from and how they were handled. The reason is simple enough: a landscape scheme is a delivery route for pests and pathogens, and the planting condition is the only point at which a local planning authority controls what arrives on site. Expect wording covering sourcing, documentation, site hygiene and replacement, and expect it on any scheme with more than a token planting plan.

The conditions are usually drafted badly. An absolute requirement for stock grown in a particular place, with no mechanism for the species that nobody grows there, is unenforceable and holds up a planting season.

Why biosecurity reaches planning conditions

Several pathogens and pests have arrived in Britain through the nursery trade or through imported soil and packaging, and the consequences fall on the public estate rather than on the importer. Authorities that have spent a decade managing ash dieback across their own tree stock are reluctant to accept new planting without knowing its provenance.

There is also a practical reason. A landscape condition already requires species, sizes and numbers, so adding sourcing and handling requirements costs the authority nothing. The planting scheme is where the control sits.

What follows is that the biosecurity requirement is rarely the subject of its own condition. It appears inside the soft landscaping condition, or inside the arboricultural method statement, which is why applicants discover it late.

Plant passports and sourcing requirements

Most plants for planting moved commercially within Great Britain require a plant passport issued by an operator authorised for the purpose, and the passport travels with the consignment. That document is the evidence a condition asks for, and it is the thing a contractor throws away.

Three requirements commonly appear in conditions, in increasing order of difficulty.

1. Retain and supply plant passports for all stock, which is straightforward if the contractor is told before delivery rather than afterwards.
2. Source from nurseries operating a recognised plant health management standard, which the industry certification scheme provides and which a growing number of suppliers hold.
3. Use stock grown within a defined geography for a defined period before supply, which is the requirement that causes problems because availability varies by species, size and season.

The third needs negotiating rather than accepting. Ask for wording that requires the stated sourcing where available, with substitution or an alternative supplier permitted on written notification supported by evidence of unavailability. Authorities generally accept that, because the alternative is a scheme that cannot be planted.

Quarantine on arrival is the forgotten element. Where stock is delivered weeks before the planting window, holding it in a defined area away from existing trees, with an inspection before planting, catches problems while they are still returnable.

Species choice where disease is established

Species selection is where biosecurity and design intent collide, and the design usually loses.

Diversity is the practical defence. Most authority guidance now discourages large single-species blocks and applies a spread across species, genera and families, so a scheme proposing an avenue of one species will be asked to justify it. That is worth anticipating in the Landscape Strategy rather than defending at discharge stage.

Movement restrictions also apply in places. Where a demarcated area is in force for a particular pest, the movement of host species into or within that area is controlled, and the controls change as the area is redrawn. Check the current position with the plant health authority rather than relying on a specification written two years ago.

Consider also what the species will face in thirty years. Planting a genus already under pressure from an established pathogen, on a site where the authority will inherit maintenance, invites an objection that has nothing to do with amenity value.

Ash dieback and existing tree stock on site

Where ash is present, the survey and the strategy need to deal with it explicitly. Three points matter.

Condition changes between surveys. A tree assessed as category B in one season can be a removal candidate the next, which is one reason a survey has a shelf life. The limits of a survey carried out outside the growing season are a related problem, covered in winter inspection limits on a tree survey.

Retention of tolerant individuals is now a recognised objective rather than an oddity. Ash showing low levels of infection within a heavily affected population has value, and a strategy that fells everything removes that. Say so in the tree survey and in the method statement.

Removal is still regulated. A Tree Preservation Order or conservation area designation still applies to a diseased tree, and the exemption for dead or dangerous trees is narrower than most contractors assume, so the notification and consent route needs following. Felling volumes above the licensing threshold also require a licence from the forestry authority.

Site hygiene and soil movement

The construction phase is where biosecurity is lost, and nothing in the planting specification protects against it.

Measures that belong in the method statement:

• Cleaning of plant, tracks and tools before arrival and between areas, with a designated wash-down point and the washings controlled.
• Footwear cleaning where operatives move between a planted area and a retained woodland.
• A single defined access route rather than opportunistic tracking across the site.
• Disposal of infected material off site to a licensed facility, with no chipping or composting of diseased material for reuse.
• Soil handling rules, since pathogens and invasive plant material travel in soil and in standing water.

Invasive species have a statutory overlay. Planting or otherwise causing certain listed species to grow in the wild is an offence under the Wildlife and Countryside Act 1981, and soil containing material from a listed species is handled as controlled waste. Treating a knotweed stand as a landscape problem rather than a waste and legal problem is how sites end up with an enforcement notice and a disposal bill.

The detail of protecting retained trees during works sits alongside this, and we set it out in biosecurity measures for tree works on a development site.

Monitoring and replacement where stock fails

Establishment is where the scheme either works or quietly dies. A five year establishment period with a replacement obligation is the common condition, and it needs three things to be effective.

The practical failure is almost always water in the first two summers, not disease. A condition that requires watering without saying who does it, how often and with what volume, produces dead stock that is then replaced and dies again.

Where a bond or other financial guarantee is in play, the replacement obligation and the guarantee need to describe the same thing, which is a drafting point rather than an arboricultural one.

Wording a condition that can be complied with

Five tests to apply to draft wording before you accept it.

Can the requirement be evidenced with a document the supply chain already produces. Does it allow substitution where a species or size is unavailable, on written notification rather than a fresh application. Is the compliance point at delivery or planting rather than before works begin, since stock does not exist years ahead of a planting season. Does it name a standard rather than describe one in the officer's own words. And is the replacement period tied to planting seasons rather than to calendar dates.

A condition failing any of those will be breached, usually by accident, and the breach will surface at the point of sale when a buyer's solicitor asks for the discharge. Which is a reason to spend half an hour on the wording at draft stage.

Enter your postcode on PlanScope to see which arboricultural and landscape documents your scheme is likely to need.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.