His "fences" consist of beach grass plants, spaced 18 inches apart.
Mountain Valley Growers in Squaw Valley, Calif., sells young lemon grass plants for $3.25 a pot at www.mountainvalleygrowers.com.
Some of the structural strength required for grass plants to stand erect comes from the leaves, particularly the leaf sheaths.
The company's greenhouses are filled with versions of tall, gangly grass plants, some developed by conventional breeding and some by genetic engineering.
But only a few metres from the contaminated soil can be found bent grass plants that are not resistant to these metals.
Ecologists at the Environmental Protection Agency said they had found a small number of the grass plants growing in central Oregon near the site of field tests that took place a few years ago.
"If you want a clue you can count up the amount of carbon that is emitted by living things – cows, sheep, grass, plants, forests and all the planet's bacteria.
A new park is being built behind the wall with teak benches along stone pathways that wind through lush grass, plants and trees: Japanese crabapple, Japanese maples, a Kwanzan cherry tree, moon shadow, periwinkle.
We learnt last week that Mariella Frostrup, the television and radio presenter, had received unwanted attention by placing a pair of pampas grass plants on the balcony of her Notting Hill flat.
"Who knew," she wrote on Twitter afterwards, "that pampas grass plants are a signal to fellow swingers?" Fellow broadcaster Esther Rantzen received similar publicity last year when she revealed how she removed the plant from her own garden after discovering the supposed connection with swinging.
This includes covering its sloping roof with local grass plants.
