What is mulch glue — and does it actually work?

"Mulch glue" has become the catch-all name for a family of products that stop loose landscaping materials — mulch, pebbles, gravel, decomposed granite — from blowing, washing or scattering away. If you've seen the TikTok videos and wondered whether it's a real thing or a gimmick, here's the straight answer for Australian conditions.

1. What it actually is

A mulch binder is a liquid adhesive that you dilute with water and spray over the surface. As it dries it forms a clear, flexible film that bonds the top layer of material together — think of it as a light net over your mulch or pebbles rather than concrete. Done properly, the bed still looks completely natural.

2. The two main types in Australia

• Spray-on concentrates (like Landscape Lock) — diluted 1:3 to 1:6 with water and applied with a normal garden pressure sprayer. Suited to mulch, decorative pebbles and DIY paths. Low cost per square metre, easy to re-apply.
• Pour-on resins — thicker polyurethane products poured neat over gravel, setting into a harder surface. Suited to high-end permanent gravel surfaces; considerably more expensive per square metre and less DIY-friendly.

3. What to check before buying any binder

• Water permeability — rain and irrigation must still reach the soil. If a product seals the surface, your plants pay for it.
• Dries clear — you want your garden looking like your garden.
• Coverage per litre — compare diluted coverage, not bottle size. A concentrate that covers 15 m² per litre beats a cheaper bottle that covers 5.
• Cure time and weather — everything in this category needs a dry window (24–72 hours) to set. No exceptions.
• Clean-up — water clean-up before curing is the difference between a 5-minute rinse and a permanent stain on your driveway. Wet hard surfaces first, rinse overspray immediately.
• Safety — check the label for plant and pet safety claims and the safety data sheet.

4. Honest expectations

• It's not permanent. A spray-on binder typically holds up to 12 months depending on weather exposure and traffic, and you re-apply when you top up mulch.
• Water temporarily softens the bond — avoid scuffing treated areas right after rain. It firms again as it dries.
• It handles wind, rain and leaf blowers — not digging dogs or brush turkeys.
• Coverage varies with how porous your material is. Buy on the conservative end; sealed concentrate keeps.

5. Where to get it

Landscape Lock is Australian owned and available in 2L, 5L and 20L in the garden care aisle at Bunnings Warehouse and selected independent stockists. Full dilution rates and step-by-step instructions for every surface are in the application guide.

These are summary instructions and general guidance only — coverage rates are indicative and vary with substrate, porosity and technique. Always follow the full instructions before applying: download the Application Guide (PDF).