As the climate changes, cities scramble to find trees that will survive

Last fall, I invited a stranger into my yard. 

Manzanita, with its peeling red bark and delicate pitcher-shaped blossoms, thrives on the dry, rocky ridges of Northern California. The small, evergreen tree or shrub is famously drought-tolerant, with some varieties capable of enduring more than 200 days between waterings. And yet here I was, gently lowering an 18-inch variety named for botanist Howard McMinn into the damp soil of Tacoma, a city in Washington known for its towering Douglas firs...