Exclusive opinion piece for Landscape & Urban Design By Dave Watson, MD of HAHN Plastics UK
Sustainability is now firmly embedded in modern landscape design, shaping material choices, procurement decisions and long-term performance expectations. Across both the public and private sectors, net zero targets increasingly influence project briefs from the outset. But an important distinction remains: are we designing for sustainability at handover, or for performance decades in use? Too often, solutions appear affordable and sustainable in the short term, yet deliver a much shorter lifespan, increasing both carbon impact and lifetime cost in the process.
Part of the challenge lies in the continued dominance of capital-led decision-making, where designers are asked to prioritise upfront cost over long-term value. When specification is driven mainly by capex, materials that meet immediate budget constraints can be favoured over those engineered to endure. The result is shorter lifecycle performance, more frequent repairs and, in some cases, premature replacement – all of which undermine wider sustainability ambitions over time.
Whole-life thinking is starting to gain traction, and while public procurement has helped formalise whole-life costing models, the same principles apply just as strongly to private developments and commercial schemes. Clients are recognising that the true cost of a landscape isn’t measured at installation, but across decades of use. A product that costs more today but performs reliably for decades can prove more economical – and significantly lower carbon – than one that needs constant intervention.
Maintenance is often the hidden variable in sustainability calculations. Repainting, sealing, surface treatments, reactive repairs and eventual replacement all carry environmental consequences, and every visit to site involves transport and additional materials – adding to the environmental footprint. By reducing the need for intervention you reduce both operational carbon and long-term cost. In practical terms, building to last simply reduces the environmental burden and operational complexity over time.
This is where material choice becomes critical. Advances in recycled and engineered systems mean designers no longer have to choose between environmental responsibility and structural performance. For example, hanitⓇ, manufactured from 100% recycled plastic, is engineered specifically for demanding outdoor applications. It doesn’t rot, splinter or require chemical treatment, and it’s resistant to moisture, frost and insect damage. Supported by long-term guarantees, it offers predictable performance over extended service lives.
The principle of “buy once, never replace” may sound bold, but it speaks directly to the infrastructure mindset we should be adopting. If fencing, edging, seating or other structural elements can remain in service for decades with minimal upkeep, this will mean fewer replacements. In turn, this means less material production, less transport, fewer site visits and less waste over time.
Of course, durability alone isn’t enough. Landscape is a visual discipline, and aesthetics matter. Our own recent research shows that while durability and ease of maintenance are strong motivators, some still question whether recycled plastic materials look as natural or refined as traditional options – a hesitation which is understandable. But manufacturing processes have evolved significantly, and contemporary recycled products now offer consistent finishes and well-considered profiles that sit comfortably within both public and private spaces, and the perception gap is narrowing.
Sustainability in landscape design cannot be judged at practical completion. It has to be measured over decades, rather than budget cycles. That means shifting the focus away from short-term financial metrics and towards whole-life cost – considering not just what something costs to install, but what it will cost to maintain, repair and eventually replace. Central to that shift is specifying materials that are durable and environmentally responsible. When products are designed to endure, maintenance is reduced, replacement cycles lengthen and the lifetime carbon footprint falls accordingly.
