Andy Spade and Anthony Sperduti like to wander New York City snapping photos with their iPhone and categorizing the pictures for their series of photo books such as "The Benefits of Looking Up" (It Books 2009, $10) which showcases views of their city that can be seen by, well, just looking up.

Going through their daily digital assortment recently, the two, who own Partners & Spade, a studio and store on Great Jones Street off the Bowery in lower Manhattan, discovered that they had a collection of what might be the hardiest of urban survivors, plants that manage to struggle through cracks in the concrete and asphalt paved sidewalks and streets of Manhattan.

"We think of them as underdog plants and who doesn't love the underdog?" Sperduti asks rhetorically when talking about their latest photo book "I Think I Can, I Think I Can" by Partners and Spade (It Books 2010, $10). 

For Spade and Sperduti, though their photos of urban underdog plants were initially an inadvertent collection, they saw that these plants conveyed a story.

"We created a criteria for gathering more photos," says Sperduti. "That included the poetry of the shot and how much of an underdog the plant was and how much concrete surrounded it. All that increased the drama of the shot."

So what does allow one plant to thrive despite a ton of cement and millions of pounding feet trying to block its way to sunshine?  Though Northwest Indiana isn't as urban of a jungle as Manhattan, it still has its share of cement and asphalt.

"In general, plants that can grow in those types of conditions are just plants that in their indigenous environments grow in hard conditions," says Patty Stimmel, senior horticulturist at Taltree Arboretum and Gardens in Valparaiso.

"In urban environments that can mean soil compaction, heat, lack of water and exhaust from cars. It also has to do with their ability to retain moisture."

Call them the survivors of the plant world, but nature seems to make some plants much more resilient than others. And when it comes to trying to grow a garden in a harsh urban landscape, it's best to choose these hardy plants versus delicate flowers that will quickly wither away.

Take, for example, the Colorado Blue Spruce. This pretty evergreen with a bluish cast to its needles wasn't just designed that way to be pretty.

According to Stimmel, the needles have a waxy coating that helps prevent moisture loss.

"That's why they're blue," she says.

Native prairie grasses, indigenous to Northwest Indiana, are also perfect for overcoming the harsher realities of life near the fast lane.

"I noticed that someone used a lot of native prairie grass like Little Blue Stem  near the Red Robin Restaurant in Valparaiso which is a great idea," says Stimmel. "Prairie grasses have fibrous roots that spread out and can tolerate lack of water because of their root systems. They can thrive in dry soil."

Stimmel, who is obviously on the lookout for wise urban gardeners, also noticed that someone at Purdue University Calumet planted a line of honey locusts.

"Honey locusts often were planted to replace American elms which died out because of elm disease," she says. "They're hardy because of their ability to retain moisture. They're very resilient and can tolerate a lot."

Some plants are not only resilient but also sneaky which just adds to their ability to rise above adversity. Take the orange lilies often seen growing alongside the highway. Stimmel says that these tiger lilies, which are also sometimes called ditch lilies -- a reference to where they're growing -- are non-native plants that have found a way to survive and replicate.

"They're opportunistic," she says, meaning they saw their chance and they took it. 

It's a great trait for living in the city.