Biosecurity and plant passports for nursery stock

A plant passport nursery stock requirement now appears in landscape specifications because the alternative is importing a pest into a site you are contractually obliged to maintain for 30 years. Every consignment of specified plants moved between professional operators in Great Britain must carry a UK plant passport, issued by an operator registered with the relevant authority. It is a traceability document, not a health certificate, and understanding that difference is the difference between a specification that works and one that reassures nobody.

Why biosecurity reached the specification stage

Two pressures met. Ash dieback removed a large part of the standard planting palette and made everyone look harder at where stock comes from. And biodiversity net gain tied developers to habitat outcomes for three decades, so a failed planting scheme is no longer a snagging item.

Authorities have responded by conditioning landscape schemes more tightly, and by asking for sourcing and biosecurity to be addressed in the submitted specification rather than left to the contractor's supplier. On larger schemes the requirement often arrives through the Landscape Strategy and is then secured by a landscape and management condition.

The commercial logic is straightforward. Replacing 200 failed whips in year three is a nuisance. Replacing a mature avenue that a quarantine pest killed, on a site subject to a 30-year management plan, is a different order of problem.

What a plant passport actually evidences

A UK plant passport is a label attached to the plant, the batch or the packaging. It carries four elements: the botanical name, the registration number of the issuing professional operator with its country code, a traceability code, and the country of origin.

That is all it does. It records who supplied the plant, what it is, and where it came from, so that if a pest is found the consignment can be traced backwards and forwards.

It does not certify that the plant is free of pests. It does not tell you where the plant was grown as opposed to where it was last held. A plant raised in continental Europe, imported and held at a British nursery for a season can be issued with a UK passport, which is lawful and entirely proper, and is also the movement pattern that carries the highest risk.

So write the specification to ask for the two things a passport does not give you: the growing history and the biosecurity management of the supplier.

Sourcing standards and provenance

Ask for three things in writing at tender stage.

• The full growing history of the stock, including every country it has been grown in and how long it spent in each.
• The nursery's certification under a recognised plant health management standard, where one is held.
• Provenance information for native species, including seed zone or region of origin.

The Plant Healthy certification scheme, built on the Plant Health Management Standard, is the usual reference point for nursery biosecurity management, and specifying it is more meaningful than specifying passports alone. UK-sourced and grown assurance covers the growing history question for native stock.

Provenance matters separately from biosecurity. Native hedging grown from imported seed can flush at the wrong time for local wildlife, which undermines the habitat outcome the planting was meant to deliver.

An illustrative example. A scheme specifies 40 semi-mature limes for a new avenue, and the supplier offers stock imported two seasons earlier and held in a British nursery. The passports are valid. The growing history shows two countries and a field lifting, and the risk profile is nothing like that of stock grown from seed in the same nursery. Ask for the history and the choice becomes obvious. The figures here are illustrative.

Set a lead time in the programme. Contract-grown stock ordered 18 months ahead is how large schemes get material that meets the specification, and it costs less than the emergency substitution that happens when nobody planned for it.

Notifiable pests and movement restrictions

Some pests trigger statutory action, and the restrictions apply to your site whether or not you knew about them.

Oak processionary moth is the clearest example for anyone planting in and around London. Demarcated areas restrict the movement of oak planting stock, and there are conditions on where oaks may be brought in from. Specifying semi-mature oak for a London scheme without checking the current demarcated area is a good way to lose a delivery.

The eight-toothed spruce bark beetle has driven demarcated areas in south-east England affecting spruce material. Phytophthora ramorum continues to generate statutory plant health notices requiring removal of infected material, most often larch and rhododendron.

Check the current position at the time of ordering rather than at the time of design. Demarcated areas move, and the map that applied when the landscape drawings were approved may not be the one that applies when the lorry arrives.

Suspected findings of notifiable pests must be reported to the relevant plant health authority. Put that duty in the contract, with a named person responsible, because a site team that does not know it has a duty will not perform it.

Inspection and quarantine on arrival

Build an acceptance procedure into the works information rather than relying on the supplier.

1. Check the passport against the delivery note and the specified batch before unloading.
2. Inspect foliage, stems, root balls and packaging for damage, insects, frass, lesions and unexpected soil.
3. Hold new stock in a defined quarantine area away from existing planting, typically for around three weeks, where the programme allows.
4. Reject and return anything that does not match the specification, before it is heeled in.
5. Keep the passports, delivery notes and inspection records for the life of the maintenance period.

That last step is the one that matters for planning. When a condition requires evidence of compliance with an approved landscape specification, the file of passports and inspection records is the evidence.

Site hygiene during planting

Soil moves pests. So do boots, tools, tyres and the water in a bowser.

Set a wash-down point at the site entrance and make its use a condition of access for landscape deliveries. Disinfect pruning tools between trees, and particularly between existing retained trees and new stock. Avoid moving spoil between a site with known disease and one without. Keep new planting away from arisings and stockpiles.

None of this is expensive. All of it is easier to write into the Construction Management Plan at the outset than to introduce after a site inspection finds a problem.

Where retained trees are involved, the protection measures under BS 5837:2012 in the Tree Survey and the biosecurity measures need to be read together, because the same fencing line usually serves both. Long-term obligations are a further layer again, covered in the note on tree management secured through a planning agreement.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.

Draft the landscape and construction documents for your scheme on PlanScope, then have the planting specification checked by your landscape architect.

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