Swimming With the Irises

In McLean, landscape designer Tom Mannion created a pool and fishpond, divided by a walkway but connected visually by iris plants.
In McLean, landscape designer Tom Mannion created a pool and fishpond, divided by a walkway but connected visually by iris plants. (By Dayna Smith -- The Washington Post)
By Adrian Higgins
Washington Post Staff Writer
Thursday, July 20, 2006

Swimming pools are as popular as ever, more so perhaps as back yards are converted into outdoor entertainment areas. Nothing wrong with that in this week of sapping heat, but for landscape designers like Tom Mannion, incorporating a pool into a garden can be tricky.

The basic rectangular pool, clear and chlorinated to death, is boring and sterile. "Water is life," said Mannion, based in Arlington, "and yet a swimming pool is not."

Landscape architects and designers are striving to make the pool a less jarring element. One popular approach is to tie it visually, if not physically, to a nearby body of water, artificial or natural.

In Europe, that barrier has been broken altogether. Swimming pools form parts of larger ponds where plantings filter the water. "I guess in theory you could have enough plant life to clean the water," said Richard Arentz, a landscape architect based in Washington. "Can you get it so clean it would meet American tastes? I don't think we are there yet, but it's promising that the Europeans are doing it."

Mannion, however, has put his toe in the water with a couple of his projects in Northern Virginia. In the first, installed in McLean three years ago, he designed a swimming pool with a submerged landing to hold three large pots. The pots are not sealed, and the roots of the plants -- miscanthus grass, canna and dwarf papyrus -- are soaked by the pool water. The chlorination doesn't seem to harm them, Mannion said. He points out that municipal tap water used to irrigate the garden also is chlorinated.

In a second project in McLean, finished last year, he designed a swimming pool with two sunken planters, each loaded with dirt, planted with water iris and mulched with gravel, which helps to hold down the soil. Look closely and you can see the gravel developing algae, but the pond is unclouded by mud and free of visible bugs, and the irises seem to be content. The effect is given a major boost with the installation of a decorative pond on the other side of a flagstone path. The pond is murkier, and enlivened by fish, iris planters mirroring those in the pool, and other aquatic plants growing out of pots. In the fishpond's center, a bubbling fountain in a decorative pot of gravel is actually a biological filter. The swimming pool has its own elaborate filtration system that includes the use of ozone injectors to reduce chlorine use.

In a moist, slow-draining swale bed flanking the fishpond, Mannion has installed bog plants. As the perennials and shrubs develop in the next couple of years, he sees a seamless progression of robust aquatic vegetation from pool to pond to plant bed. He wants the owners, Dick and Viki Clark, to think of the path as a bridge and to believe that the two bodies of water are linked, the fish simply preferring to stay on one side.

Something so modest, however, has left pond maintenance companies scratching their heads. One refused to even consider taking on the contract, saying the firm had one account where the in-pool cleaning robot got dislodged and started squirting chlorinated water into an adjoining fishpond, killing the koi. Others said they couldn't guarantee that the pool would remain "pristine."

"I assume they thought the soil would be like smoke moving through a room if it got into the water, which it just does not do," Mannion said.

Mannion told the pond construction company that any winter cover would need cutouts for the irises. The Clarks opted instead to place a leaf net over the ponds in the fall and to spend extra time in the spring removing windblown debris. Viki Clark, who is known as Jan, said she "can't wait" for the plants to fill out and Mannion's vision to become a reality.

Mannion is a disciple of Dutch designer Henk Weijers and went to see Weijers's naturalistic swimming pool projects in Europe in 1995.

"It's taken me 11 years to work up the courage to do this," Mannion said. "This is an extremely overdue gesture toward the beauty of Henk Weijers's projects." Mannion conceded, however, that filtering pool water through an adjoining artificial wetland would be much more difficult here because mosquitoes are a bigger problem in the United States than in Western Europe.

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