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A 'Magical Thing' for the Garden
by Vanessa Gardner Nagel, APLD

When I explained to my husband that we needed to remove some lawn, I knew I was “sending a shot across the bow”.  Men don’t let go of their lawns easily.  But a dry area, beneath a limbed-up fir tree, doesn’t grow grass well.  I told him that we could grow something low, green and drought-tolerant there – maybe thyme – to replace the blonde haze that was dying to be lawn.  After answering questions like “Couldn’t we water more there?” and “Would fertilizer help?” he halfheartedly agreed.  He knew in a battle for elements, Mother Nature would win. 

Inspired by a theme for our garden ( Nicolas Roerich’s “Peace Through Culture” philosophy), I wanted to design something that would express that philosophy.  The area was somewhat circular and would easily transition into a full circle of thyme.  A two foot hard-scape ring around the circle to walk and get the lawn mower to the lawn was added around the circle.  Our plan evolved into a 12-foot diameter, 2 foot wide ring around an 8-foot circle.  The metaphor of a ‘circle of time’ began a search for a symbol that would fit with our quasi-Asian-themed garden.  The search led to an Ouroboros – a multi-cultural figure for the circle or continuity of time.  It is a snake or dragon coiled in a circle, eating its tail.  With my computer as a design tool, the pattern in the ring soon became a spiraling dragon pebble mosaic.  With design in hand, I approached Portland pebble mosaic artist, Jeff Bale, to execute our dragon.  Our initial consultation determined the colors of pebbles, based on availability, and general directions for prepping the area.

Prior to Jeff’s arrival the area had to be dug to a depth of approximately 6 inches.  The inner and outer edges of the ring were defined with concrete pavers that were short enough to work with the radius of the circles – 6” x 8” x 2”.  The paver edges had to be level.  Three inches of 5/8 minus gravel were packed well inside the ring, while additional amended soil was added to the circle.  Bags of mortar, colored pebbles and lengths of rebar were assembled near the site.  Pebbles were sorted into separate buckets according to color (many were already pre-sorted when purchased).   It would have helped had I also sorted by size and shape in advance of installation.  My print service plotted the design to full-scale and I transferred it to clear Mylar, since we were anticipating some inclement weather.  And so began a project through 4-1/2 rainy days of April.

Jeff came with energy, enthusiasm, and wheelbarrow for creating “a magical thing”.  Jeff sets his pebble mosaics directly into wet mortar, which he feels is superior to the dry-mortar and sand method because there is less space needed between pebbles.  Lengths of rebar were curved and laid on top of the gravel bed to prevent the 2-foot wide ring from cracking later.  The hose was brought close to the site with a squeeze-handle “gun-type” spray nozzle attached.  Water was an important element during the entire process, not only to use for mixing mortar, but also to thoroughly wet the area about to receive mortar, keep pebbles wet before being set, and hose off the design to prevent too much mortar from sticking to the pebbles.  Mortar was mixed to a consistency where it would form a ball and maintain its form when packed into the ring. 

The buckets of colored pebbles were nearby and sorted by size and shape as the installation progressed.  The size and shape of the pebbles determines the degree of detail in the mosaic pattern and its ability to adhere into the mortar.  One bag of mortar was mixed at a time – more than that would set up too quickly for inserting the pebbles – even in the cool days of April.  After the mortar was inside the ring, the pattern was laid over the area and transferred via a sharp stick (it was handy) into the mortar.  The pebbles were set into the mortar according to the predetermined color of each area, spacing them as closely as possible.  (One could also create a template, outline the template with pebbles and fill in the area when the template is removed.)  Once the section was completely full of pebbles, a piece of ¾” plywood large enough to cover each new section of mosaic was laid on top of the newly laid section.  Jeff stomped atop the plywood to achieve a level mosaic, using the edge pavers as a screed. 

When the mortar was fairly well set (about 20 minutes in 55 degree weather), the edge of left over mortar was cut away.  This left an edge where the next batch of mortar could be placed as close to the first batch as possible and set the new pebbles immediately next to the already set pebbles to create an indistinguishable transition.  The design was sprayed with water to remove as much excess mortar as possible before the next section was added.  This process continued all the way around the ring, using approximately 18 bags of mortar.   Each bag made about a 16” x 24” portion of the mosaic.

Inside the mosaic, I mounded up the soil and placed a large pot in the center.  I planted a variety of thymes around the pot inside the mosaic.  They bloom at different times and give a “Persian carpet” effect as they knit together.

Three weeks elapsed (recommended by Jeff).  With muriatic acid from a local pool supply house, my neighbor’s NIOSH-approved respirator, safety glasses, old clothes, chemical proof gloves and some old rags, I carefully rubbed the mosaic with a little acid at a time to remove all excess mortar and the “haze” that was over the pebbles.  (Use muriatic acid with extreme caution!)  When done, I hosed the mosaic and the surrounding plants thoroughly.  A clear, shiny, protective coating could be applied to the mosaic at this point, but I chose to allow the mosaic to intensify with rain or sprinkler. 

Our mosaic is now a “magical thing” in our garden.  And one good thing leads to another.  My husband let go of a little more lawn in the dry shade of another fir tree.  Plans for a new pebble mosaic – a phoenix - nearer the house are under way.  Besides, we have a lot of extra pebbles and they need to go somewhere. 

Note: this pebble mosaic design was given an Award of Excellence in Sunset Magazine's 2004 Landscape Design Competition.

A Magical Thing-1Jeff carefully puts in each pebble.

 

 



A Magical Thing-2Bulbs emerging through thyme in spring.

 


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A Magical ThingMid-summer at the pebble mosaic.

 

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