In the inland Northwest our primary native conifers are ponderosa pines.
They are normally deep rooted, so people here plant under them all the time,
especially if they have underground sprinkler systems for the lawns. Under
one of mine quite close to the trunk, I have a rhododendron, an oriental
lily, several asiatic lilies, a hosta, and a climbing hydrangea. A little
further away, but still within the drip line, I have ferns, foxgloves,
primroses, columbine, etc.