When it comes to sustainable practices in the landscape, we look to nature for examples. For instance, we use compost, leaf litter, manures and other organic matter to improve our soil. Nature uses these elements, too. We only have to walk in woods and look at the ground to see bits of leaves and other plant debris layered in the soil. Animals make their contributions, too.

There’s something about water that’s good for the soul. A bubbling fountain, a cascading waterfall or a tranquil pond just makes us feel good. Even before Nebuchadnezzar built his hanging gardens 2,600 years ago, landscapers understood the aesthetic and psychological benefits of building water features into their designs...