Saturday, April 14, 2012

Gravel gardens that never have to be weeded

Today I saw my neighbor, John Lewison, at work on his terrace--at 539 S. Owen Drive.  He was halfway through planting a "gravel garden," when he stopped to show me how.

Gravel gardens were developed in Germany, where studies indicate labor savings of 85% over a conventional garden.

Roy's garden

The  concept was presented by Roy Diblik on WPT:  You lay down 5" of gravel over good soil.  Roy used small quartzite chips, because they don't break down.  Other kinds of rock, especially limestone, break down to create soil, which weeds could then invade.  Edging keeps the gravel from mixing with soil or wood chips in the next garden.

Roy planted drought-tolerant plants: Autumn moor grass, Arkansas mint, and prairie dropseed.

The plants are grown in 5" pots, then transplanted into the gravel, by simply pushing the gravel aside for each plant.  They have to be watered every 1-2 days for 8-12 weeks, while getting their roots into the good soil below the gravel.  After that, you never have to water or weed.  Roy says he's  pulled only six weeds in three years from a large gravel garden. 

Although there's no watering or weeding, some maintenance is required.  Fall leaves have to be removed, and the dead crowns of the plants are cut and removed in spring.  This keeps organic matter out of the gravel, where it might create soil.  The garden should last for 30 years.

John's variation

John is modifying the concept to create a rain garden on his terrace.  John hopes to infiltrate a substantial amount of runoff coming from his wide driveway.  During the winter, runoff here makes an icy puddle at a low spot on the sidewalk.

John, a professional landscaper, rototilled the soil, to make it easy to remove.   His plot is about 5' wide by 12' long.  After shoveling out soil to a depth of one foot, he replaced it with 6" of top-quality topsoil. This was necessary because terrace soil below the top few inches usually isn't very good

Then he shoveled in 5" of rounded stream gravel which-- like quartzite--won't break down.
He needed 3/4 of a cubic yard, costing $100. 

Next come the plants.   Stay tuned.