Interlock and River Rock: Pros and Cons

Interlocked sidewalks or driveways/laneways and river rock instead of lawns may look nice and tidy until the weeds move in. And they will try, you just have to stay on top of them for a winning look.

Weeds are inevitable as their seeds blow around in the wind, lodging themselves in the cracks between the interlocked stones or river rock. They can settle into the tiniest of cracks and then sprout to become a huge mess. Don’t disparage the contractor that you paid to make your yard look nice, it is not (generally) their fault. Weeds and wind are facts of nature.

Polymer Sand Between Interlock

Most landscapers use polymer sand, AKA hardscape, jointing, or paver sand, a mixture of fine grains of sand and bonding agents. These products fill in the cracks between the interlock stones of sidewalks, patios, and driveways. The benefits are stability (the stones don’t shift), weed control, and even insect control.

The problem is, even when applied properly (there is a specific method of applying polymer sand) weed seeds will still congregate on top.

The most recent look in interlock involves larger slabs of stone, meaning fewer cracks for weed seeds to invade and you to keep clean. That’s a move in the right direction.

Landscape Fabric Under River Rock

Landscape fabric is (should be) used under river rock when it replaces lawns to help keep weeds from poking through from underneath. Some aggressive weeds still do manage to get through the barrier though. As mentioned above, nothing prevents weed seeds from blowing from above and settling between the rocks.

Landscape fabric can be purchased in (very) large rolls or smaller, more manageable rolls. Regardless of the roll size, choose the heavy-duty kind.

Unstable Footing

One of my biggest complaints about landscaping with river rock is the instability of the rock surface for anyone walking on it. That would be me working in a client’s garden. Even though I always wear stable shoes, I still find the rocks unstable to walk on so worry about twisted ankles.

I do find the smaller stones more stable than the larger ones.

Interlock and River Rock, pros and cons

Vinegar to Kill and Deter Weeds in Interlock or River Rock

Vinegar, and not just regular vinegar but the extra strength “cleaning” vinegar, works well to kill any weeds that do manage to sprout between the cracks of your interlock or stones/rocks. It also deters new weeds from sprouting. I put the vinegar in a large pressurized sprayer to make large applications easier.

Interlock and River Rock, weeds

Weed Torches to Keep Interlock and River Rock Tidy

Another method of removing weeds that have sprouted between the cracks of your walkways or patios or your river rock is a propane-powered weed torch. I have yet to try one but have heard only good reviews on them.

Conclusions

I don’t mean to discourage anyone from replacing their old, outdated walkways with much prettier interlock or their lawns with river rock, but want people to be aware these types of landscaping still require work. Lots of work.

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