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When you go shopping for products that might help with problems you have in your garden, you might spot landscape glue. It is right next to the pesticides and herbicides — a pretty good clue they’re not exactly friends of a sustainable garden. Products like landscape glue, pebble glue, gravel binder, decorative stone adhesive, and resin binder (often sold under various “lock” brand names) promise a perfectly neat, no-fuss look. They’re sprayed over pebbles, gravel, or mulch to hold everything in place, preventing movement from wind or rain. But that tidy finish comes with hidden costs for you, your garden’s and the wider environment’s health.

What is in landscape glue?

The vast majority of these products have one of two active ingredients in them that create a semi-permanent bond between the material it is applied to. These products are either water-based polyurethane or acrylic polymers. They may also have other additives like filling agents, plasticizers, or solvents. When applied, the liquid makes the material shiny, clear and static.  The claims that these products are low maintenance are based around their reducing weeds, keeping stones or mulch in place, and creating a neat appearance.

Healthy Concerns

Landscape glue poses significant health and environmental concerns that are often downplayed by marketing claims. According to the Safety Data Sheet, the product is highly hazardous to humans during application, with risks to the skin, eyes, and respiratory system if proper protective equipment is not used. Beyond the effects on human health, it is also toxic to aquatic organisms, raising serious questions about its impact if residues wash into waterways. Despite this, some manufacturers boldly claim on bottle labels that the product is “safe for plants, animals and humans”— a statement that appears misleading and contradictory to the detailed warnings provided in their own documentation. This discrepancy highlights the importance of reading Safety Data Sheets carefully rather than relying on marketing slogans that can obscure real risks.

Environmental and Sustainability Concerns

The environmental impacts of landscape glues are well-known, but people don’t usually link them to this product –

A picture of cupping hands that have tiny pieces of microplastics in it. The hands are over waterMicroplastic Pollution

Polyurethane and acrylic polymers are plastics — even if water-based, they don’t biodegrade in any meaningful timeframe.  Over time, weathering and UV light cause the bonded surface to break into microplastics.  These particles infiltrate soil ecosystems and can leach into stormwater, eventually reaching waterways. Microplastics can be ingested by soil organisms, insects and aquatic life, disrupting feeding and reproduction and have recently been linked to many human health issues, such as cancer.

Soil Life Disruption

Many of these products claim to allow water and air through, but in reality, the hardened bonded layer restricts the natural exchange of air, moisture and organic matter between the surface and the soil. This effectively suffocates beneficial microbes, fungi and invertebrates — all crucial players in the nutrient cycling that keeps soil and plants healthy. Worms and burrowing insects can’t move freely beneath a glued surface and the resulting drop in biodiversity leaves the soil less able to withstand drought, pests and disease. Some might argue that such locked surfaces are no different from a non-permeable path like concrete, but the key difference is that resin-based glues gradually break down, releasing plastics and additives into the environment.

Chemical Leaching

These products contain plasticizers, fillers and solvents that can leach into soil, particularly as the product weathers.  These additives may include phthalates, formaldehyde-releasing agents and heavy-metal catalysts.  Runoff can carry these into drains and waterways where they affect aquatic organisms.

a heavily pebble landscapes garden with contrasting white and grey pebbles with not a single one out of placeHeat Island & Water Stress

The sealing process often darkens the pebble surface which then increases the amount of heat it absorbs and radiates.  This is certainly a lot more than vegetated areas. Such heating stresses nearby plants and can raise garden the temperature of microclimates making them less hospitable for sensitive species.

Misleading Claims

Landscape glues are marketed as “Water-based”, but this only refers to the carrier before curing — the final product is still plastic.  These products are often advertised as “low VOC” or “non-toxic” during application, which hides the problem of long-term environmental persistence.  Weed seeds still blow in and grow between glued stones — but are harder to remove.  It reminds me of artificial grass and how that is advertised as an easy, low maintenance option to reduce weed growth when, in fact, it isn’t.

End-of-Life Waste

Once pebbles are glued together with landscape adhesive, they become a single block of stone and plastic. Some makers claim the glue eventually breaks down, but what about the stones where it doesn’t or those left with glue residue and the impacts of breakdown products? Because the adhesive is so hard to remove the stones can’t be reused or recycled like loose gravel. Taking glued layers apart usually means using heavy tools or harsh chemicals – a task which is messy and difficult. In most cases, the whole surface ends up in landfill. The real issue isn’t the stone—it’s the plastic glue which breaks down extremely slowly and can remain in the environment for decades or even centuries.

Gloved hands are scooping up bark mulch and applying it to a garden bedSustainable Alternatives  

Most of you will appreciate the negative impact of these landscape glues, but as a gardener you are an influencer, so talking to other gardeners and friends about it is really important.  And talking about alternatives to using pebbles with glues is a part of that: 

  • Loose Pebbles with Weed-Suppressing Groundcovers – Use plants like creeping thyme, dichondra, or native low-growers.
  • Organic Mulches – Wood chips, bark, straw feed soil as they break down.
  • Permeable Hardscaping – Unbonded gravel, pavers with wide joints, permeable concrete.

Gardens work best when they’re alive and changing, not fixed in place. Healthy gardens let rain soak into the ground, give soil creatures air and food and adapt naturally with the seasons. Such adaptation keeps the soil rich, supports plants and wildlife and makes the garden stronger over time. Using landscape glue does the opposite—it seals the surface, blocks water and air from reaching the soil and stops natural cycles from happening. Instead of helping the garden thrive, glued surfaces create a hard, lifeless layer that gets in the way of ecological gardening.

In the end, pebble glue might make a garden look neat for a while, but it comes at a cost to you, your garden and the wider environment. Not only does a glued surface stop soil from breathing and slows other natural systems, but it also stops you having flexibility to tinker and to move and change things in your garden.   The easiest and quickest way to make your organic garden look neater is to have messy ecosystems in orderly frames (Nassauer 1995).  Use natural materials for paths and to edge your garden beds so that you are working with nature. Such materials will support soil, plants and wildlife and allow resources to be recycled or returned to the earth.

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