So, how do you plant shade trees on a shallow slab over a freeway? That was one of the hurdles planners had to overcome at the new Klyde Warren Park opening in downtown Dallas.
The fourth floor view from the offices of the Woodall Rogers Park Foundation isn’t what it used to be.
For three city blocks the solid stream of traffic threading its way into the freeway’s tunnel has disappeared. It’s been covered up by a park that sits on top of the freeway like a fancy lid decorating a box.
Jody Grant likes what he sees.
“We were trying to unify Dallas,” said Grant. “This whole area was divided by the freeway that was here. Hopefully we’ve created what will become the town square of not only the Arts District but of Dallas well.”
Grant is the co-founder of Texas Capital Bancshares. Over the past eight years he and his wife Sheila have led the effort to raise $51 million dollars in private money, about half the cost of the $110 million Klyde Warren deck park. Public money pays for most of the rest.
“This is the great lawn,” explains Grant as he heads down a crushed granite path that surrounds turf-like Bermuda.
“It’s where we can have intimate performances or we can accommodate three, four, five thousand people.”
This is a park for doing things, but includes pockets of natural and architectural beauty. Its five acres include a stage for performances; an area for ping pong and table games; a dog park; a children’s playground with fountains and trees, lots of trees: 322 to be exact.
Grant says shade to provide cover during Dallas’ triple-digit summers was the number-one objective for landscaping, but how to provide big enough trees was one of the big mechanical challenges.
To begin with, the distance from the park surface down to the highway ceiling, is just six-and-a-half feet. And many of the primary trees lining the pathways are Shumard Red Oaks which in normal conditions grow to 80 feet and need room for their roots.
Landscape architect James Burnett says the solution was a grid of underground planter boxes that contain the soil and trees. The planters are supported by massive, load-carrying beams that hold the park above the highway.
“The trees are in their tray, that trench that runs across the park. It’s a planter box that’s four-and-a-half feet tall, four-and-a-half feet wide and eight feet long,” said Burnett.
Burnett says because the park’s Shumard Oaks are essentially potted plants they will only grow to about half their normal size, about 35 feet. But that will be enough to help provide shade for 65 percent of the park.
To offset the weight of the soil needed for trees architects are using something called Geofoam beneath the Bermuda grass lawn.
Burnett says the grass is grown in 12 inches of soil which rests on three feet of the high-density Styrofoam.
“It’s such high density you could drive an 18- wheeler over it and it wouldn’t deflect at all,” said Burnett.
Burnett’s design includes 32 native or adapted plant species that will need limited amounts of water and maintenance including Red Oaks, Pond Cypress and Chinese Pistache trees.
Red yuccas, purple-blossomed Texas Sage, and yellow coreopsis will add splashes of color. Mexican feather grass; Indian grass and bluestem will put on a show as they sway in the breeze.
Jody Grant believes the many years of planning have created a healthy balance between the natural and the manmade. He says he’ll know for sure when the Klyde Warren Park opens to the public Saturday and its first customers weigh in.
“I hope they’ll say, ‘wow’, and want to come back,” said Grant . “That’s the key to a successful park.”