The Gravel Barrier Experiment

[mishalak]

This is an experiment. I am trying to keep a very nice lilac bush from growing into my herb garden. I saw a recommendation to dig a trench, line it with barrier cloth, and then fill it with gravel. Roots encountering the barrier should grow down instead of across. It will take a couple years to evaluate this system, but it seems like it should work.

To be a bit more precise my trench is about 12cm/5in across and 20cm/8in deep. The barrier cloth is run longways in the trench and folded back on itself rather than cut down to fit the trench. The top is folded toward the plants to direct their roots down along the side. Bricks, being about 20cm/8in long cover the top almost completely except on curves. Knowing that UV light will break down the barrier cloth I put some leaves and sticks up against the bricks to keep some of the light off those edges.

When putting in the gravel I added in stages so that dirt could be added outside where I accidentally made the trench too wide. The extra bricks are to add places to step. The brick “knots” visible to the right in some pictures are also places to walk in the herb garden when weeding or picking plants.



The bricks are on top of the soil, rather than dug in, because this way there is room for leaves and sticks to form a mulch/compost layer about 6cm/2.5cm deep. Where the bricks needed to be angled or where it went through the fence the roll is topped with more gravel to protect the top of the roll.

Personally I think it looks better with curves rather than trying to make it perfectly straight. Also being practical that I cannot make bricks run in a straight line. All my garden paths look a bit “rustic”.

Comments

[jcfiala]

I think that could look kinda cool. I hope it works!

[mishalak]

This spring will say a lot about how well or not it will work.