Interlock and River Rock: Pros and Cons

Interlocked sidewalks or driveways/laneways and river rock instead of lawn 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 wind, lodging themselves in the cracks between the interlocked stones or river rock. They can settle into the tiniest of cracks 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 less 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 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 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.

photo credit: Pexels free photos

Next Gardens4U Project

My most recent Gardens4U project involved two new garden beds for the back corners of a large, pie-shaped lot. The yard has a large swimming pool so the corner beds were placed far enough way that pool water will not splash onto the plantings. The clients’ own three dogs, so my plans also had to allow for a running area between the flower beds and the pool. Check out the before and after shots…

To save my time (not to mention my back) and the expense involved, the client dug out the beds after I marked them out. I added composted manure to improve the clay-laden soil, then arranged the perennials and shrubs according to their potential sizes at maturity as well as their bloom time and colour.

When the temperatures cooled off a bit, and I was happy with the placement of plants, I spent half a day planting them in their new beds. Note the drain in one corner bed, a low point in the area that rainwater from several adjacent lots drain into. It is imperative that this drainage site not be adversely affected when adding soil and plants. Although this consideration makes the one bed appear oddly shaped and lacking soil, the drain will not be visible when the plants grow to mature size. After planting, the garden beds were then edged to leave a clear demarcation line between the gardens and the lawn…

Once the perennials and shrubs were watered in well, (every day for a week) I added dark brown, cedar mulch for the finishing touch. The plantings may look a bit sparse right now, but in a few seasons from now they will have reached their full, mature size. If I plant too many plants and too close together, I will have unhappy clients in a few years…

I also talked the clients into outlining the perimeter of their above-ground pool with river rock. They did this project themselves; I think it looks great!

pool edged with river rock

You can see the one corner garden at the back left, peeking out from behind the pool. Onto the next project! Now that the weather has cooled off I can get more done before garden fall cleanups start.