A conversation between Benjamin White, co-founder of A&B Smart Materials and Romy Rawlings FLI FRSA, Director of DeepGreen.

Ben is a chemist-turned-entrepreneur and runs an Oxford-based startup. His work on biodegradable alternatives to conventional plastics stems from his background in polymer engineering during his PhD research into drug delivery systems for chemotherapy. That research into nanoparticles and synthetic polymers for medical applications demonstrated the fundamental chemistry behind how materials interact with biological systems. To say I felt slightly out of depth during our chat is an understatement!

Out of Sight, Out of Mind?

As landscape professionals, we consider sustainability in so many ways, for instance championing biodiversity enhancement, specifying peat-free compost, and scrutinising the carbon footprint of materials. But there's an invisible pollutant hiding in plain sight across every one of our projects, deriving from our specifications for products including tree protection and soils. Microplastics are everywhere in the landscape, and most of us are unaware of both the scale of the problem and our role in perpetuating it.

Associated with this, one of Ben’s many fascinating research threads is a pressing environmental challenge: super absorbent polymers (SAPs). These are synthetic plastic materials that most of us have never heard of but encounter daily, for instance in feminine hygiene products and nappies. SAPs are also used in agricultural and horticultural applications where they’re invaluable in drought management and intensive farming operations. Uses include the establishment of trees in challenging conditions or the creation of specialist soil mixes, where improved water retention is required. They're remarkable materials from a technical perspective, absorbing hundreds of times their own weight in water and releasing it slowly over time. But their persistence in the environment creates a legacy problem that's only now becoming apparent.

“The big issue is that these materials are fantastic at their job. But when they end up in the environment, they don’t biodegrade. They slowly break up into smaller and smaller chunks - microplastics - which end up in the water, in the land, in rivers, in our food, in us.”

Our conversation expanded from SAPs into other plastics that we commonly specify or use in the landscape sector - including tree establishment products, artificial grass, pelleted seed coatings, and slow-release fertilisers. Another important consideration is the provision of lightweight soils for podium and roof gardens: as the demand for ‘urban greening’ continues apace we risk bringing in more toxins along with hydrogel products that reduce the irrigation demand.

The Health Connection: a Ticking Bomb

While we’re all aware of the environmental issues around microplastics, they’re also increasingly linked to serious human health impacts: reduced fertility and elevated cancer rates among them. Recent studies have found microplastics in human blood, lungs, placentas, even breast milk, and we're just beginning to understand the full extent of the threat.

“We’re only really discovering the effects of microplastics on people in the last 20 to 30 years, so we don’t actually know the true extent of the harm they might do, which is very concerning.”

Beyond human health, microplastics also create serious infrastructure problems that cost millions to address. For instance, the infamous fatbergs clogging our sewers aren't only composed of cooking fat and wet wipes. They're also made up of super absorbent materials from hygiene products that swell dramatically when saturated with water. These same materials also constitute some 5% of landfill volumes - a massive waste stream that is ever increasing.

In light of all this, there is stricter legislation on the horizon, at least in the EU: in October 2023, the EU adopted Regulation (EU) 2023/2055, which includes the banning of intentionally added microplastics (synthetic polymer microparticles less than 5mm, insoluble, and resistant to degradation). This regulation has a phased implementation timeline, with key deadlines for agricultural and soil-related products coming in 2028. Whether we in the UK will be subject to these mandatory restrictions is to be seen but it’s likely that they will ultimately impact us since most manufacturing takes place in the EU.

The Carbon Conundrum

To address this impending deadline, Ben is developing biodegradable alternatives based on modified starches and natural polysaccharides (complex carbohydrates derived from plant sources). Unlike synthetic polymers that resist biological breakdown, these materials are designed to be broken down by naturally occurring bacteria and enzymes in soil and water environments, converting them into simple sugars. I found It fascinating that Ben can assign any product a bespoke lifetime by crosslinking the chemical formulae. So, a tree tie might be programmed to degrade after 3 years, fertiliser coatings within six months, or an absorbent soil gel assigned a life of five years.

But Ben’s impactful research isn't without complexity:

“Interestingly, life cycle assessments (LCAs) reveal a counterintuitive result where biodegradable materials can produce more CO2 over their full lifecycle because they break down completely, releasing more carbon dioxide in the process. Meanwhile, synthetic materials that persist indefinitely don’t release as much CO2, representing a form of delayed environmental accounting where the true costs simply aren’t being measured.”

Hence a material that scores well on carbon but creates persistent pollution may be far worse for overall environmental health than one with a higher carbon footprint but genuine biodegradability. This highlights a critical need for more holistic environmental assessments (LCAs or Environmental Product Declarations) that go beyond simple carbon accounting; something I’ve been advocating for a very long time! We must consider a broader range of impacts including toxicity, bioaccumulation, ecosystem disruption, and long-term persistence alongside greenhouse gas emissions.

How Much??!

A familiar refrain in sustainability circles rings depressingly true here too: everyone wants environmentally responsible solutions until they see the price. This gap between stated values and purchasing decisions is one of the most frustrating realities for those of us working in truly sustainable businesses. The dynamic inevitably plays out in procurement where sustainability is pushed in early design conversations, but value engineering so often ruthlessly eliminates premium, and less damaging, options.

A typical example might be a contractor who expressed interest in biodegradable tree guards but ultimately orders conventional plastic because it's marginally cheaper per unit, but will be multiplied by potentially thousands of trees.

Or a client in London (never mind southern Europe or the Middle East!) with a roof garden that requires irrigation three or four times a day throughout a dry summer simply to keep the plants alive. Who’s counting the cost of that level of maintenance or the waste of potable water in an environment where we face a water deficit by 2025?

So, as ever, we must shift our thinking to whole life cost…

Who Cares Beyond Practical Completion?

Anyone who's returned to a landscape scheme planted some years ago knows the sight all too well: plastic tree guards wrapped around mature trunks, degraded shelters and mulch mats flapping in the wind, or tree ties throttling established trees. Establishment support that was meant to be temporary has become permanent because nobody has budgeted for or executed its removal.

This reality is universal: few planting schemes receive the necessary maintenance, not through malice or negligence, but simple economics. Maintenance budgets get cut. Contractors change. Responsibilities become unclear. The temporary measures installed with the best intentions become permanent environmental problems. The particles don't disappear: they become part of the substrate, entering drainage systems, transported in runoff, and accumulating in ecosystems.

This is where our maintenance reality creates a genuine economic opportunity for biodegradable materials. If we could truly eliminate the need for removal and disposal - where products break down as trees establish - that convenience could fundamentally shift the cost-benefit calculation. This means accounting for the true costs of conventional tree protection over a project lifecycle, where the initial purchase price is just the beginning. Scheduling removal means revisiting a site, often years after initial planting, with hours spent removing guards, ties etc. That material requires disposal, usually to landfill. And in many instances, there’s the long-term damage to trees to consider when they’ve been strangled and will ultimately fail.

“Compare that to a truly biodegradable alternative that costs perhaps 30% more initially but requires zero removal, zero disposal, zero return visits. The nominal price premium becomes a genuine saving when lifecycle costs are properly considered...”

Suppliers have been responding to this demand for some time with products labelled as biodegradable or eco-friendly. But critical questions remain largely unanswered in many specifications. How quickly do these materials truly degrade in field conditions? What do they break down into: are we simply replacing large pieces of plastic with smaller fragments? Do ‘biodegradable’ claims actually deliver in practice, or do they constitute greenwashing? Does a material that degrades slowly over five to ten years solve the problem if trees establish in two to three? These are questions we need to ask more forcefully of suppliers.

A Green and Plastic Land?

The conversation around microplastics in horticulture is growing, and it needs to accelerate rapidly. While the largest markets for alternatives to synthetic SAPs are in feminine hygiene products and large-scale agricultural applications, we in the landscape industry have both a responsibility and an opportunity to show leadership.

Landscape professionals specify materials that will remain in the ground for decades, sometimes centuries. We create environments explicitly intended to enhance rather than degrade ecosystem health. We work at the interface between human infrastructure and natural systems. And we have the collective procurement power to drive demand for genuinely sustainable alternatives, as long as we're willing to ask the right questions, demand proper evidence, and accept higher capital costs for better long-term outcomes. A familiar refrain in so many of my conversations…

The questions we should be asking are becoming clearer with every study published on microplastic pollution. The health and environmental stakes are too high to ignore, and the evidence is mounting too quickly. Microplastics are found in us, in Arctic ice, in the deepest ocean trenches, and in every terrestrial ecosystem studied. Their health impacts on humans and wildlife are increasingly well-documented and the problem we've created isn’t going away: it compounds with every tree guard specified, every mulch mat installed, every plastic-coated fertiliser applied.

The microplastic problem in our landscapes won't solve itself through market forces alone. It requires active intervention through specifications that demand better technical performance than vague ‘eco-friendly’ claims and much clearer insight into what ‘biodegradable’ really means in landscape applications. We need procurement processes that value lifecycle costs over purchase price, design approaches that minimise plastic use, and professional advocacy for stronger standards and regulations. We need to create market pull for innovative products and early adopters.

Awareness is the essential first step toward that change. Landscape professionals are uniquely positioned to drive demand for solutions that truly return to the earth rather than simply fragmenting into smaller pieces that will haunt future generations. Every specification written, every product selected, every tender document issued is an opportunity to make different choices.

The challenge is significant, but so is the opportunity. We can be the profession that recognises microplastic pollution for the serious threat it represents and takes meaningful action, or we can continue specifying the same materials we always have until regulations force change upon us. Do we wait for legislation or do the right thing now? The choice, ultimately, is ours. If you want to see change, Ben would like to talk...

#4 Lurking in Our Landscapes: the Menace of Microplastics