divaqs's Blog

Planting in Garden Rock Walls
Apr 26, 2007 | 9:55 AM PST
Tags: Strawberries , garden rock , retaining walls , corsican mint , thyme

I can’t speak for other places, but in the Seattle area it is common to see a lot of retaining walls built from large basalt or granite garden rocks stacked to form walls. When visiting Japan more than a decade ago, I saw some of these same garden rock walls, but they had been designed with a wonderful selection of plants growing out of them, which turned them into a beautiful extension of the landscape, rather than a purely plain and functional aspect.

When I bought my house, I discovered that the previous owners had scattered a couple of dump truck loads of large garden rocks all over the yard, in a seemingly random pattern. I spent a couple of years moving them to form retaining walls or rock stairways. It was great exercise and kind of fun moving all those 1 to 3 man size boulders around by hand.  

While I had been building the rock walls, I realized that I wanted to beautify them like I had seen done in Japan, and definitely didn’t want the great southern light exposure to go to waste. So I backfilled the rocks with good garden soil and began planting strawberries and herbs in all the nooks and crannies that I could.  

While this helped limit the expansion of strawberry plants, it presented extra challenges on them getting enough water, since water tended to drain down the backside of the rocks and sometimes miss the strawberries. I experimented with different soils and had the greatest success with a richer compost based soil, since it can retain water better. I also experimented with trying to form cupping shapes around the base of the plants with compacted compost, in order to catch and hold on to the water longer, which also seemed to help. The first year was the hardest and some planting years I seemed to lose about half of my new strawberry plants, but once they get a good root system, the strawberries seemed to do okay.

 

While the rockery does limit the strawberries aggressive expansion, it doesn’t completely stop it. Every spring I do need to still remove or move strawberry plants that spread into the bordering planting areas before planting in them. Without the natural control of the rockery, it would be much worse.

In this below picture you can see an example of the spread of strawberries into my planting area.

 

While cleaning up the bordering planting areas is when I usually move strawberries to new places among the rocks, or replace ones that died or are struggling.

I don’t just have strawberries growing in rocks, but also have a variety of herbs intermingled as well, such as Corsican mint and Creeping Thyme.

 

I am planning on expanding to including more edible plants intermingled among the rocks, but am planning on strawberries being the foundational plant in the design.