Plunker, mostly. Even my tiny front yard has a big mix of soils and sun exposure, so I am constantly plugging in and moving things around. Being in the Dallas area, generally only get what at maturity can survive on minimal, if any, supplemental water, but even there I will experiment, like with roses.
Do have a baseline in three of the areas. Sort of skeletal structure to those where Bearded Iris and Daylilies make up the framework, especially in and around a line of Rose of Sharons in tree form growing along the driveway. I stick other things in among them that might work with color and offer some textural contrast. The ROS are the only things the original owners had besides one scraggly holly shrub and a nasty photina up by the house, and a narrow but tall shrub-form crape myrtle along the west property line. Had a contractor dig that last one out to install decorative fence panels and I'm STILL finding pieces of the roots growing back up. I like tree form crapes a lot, but my goodness!
Been wresting something a little more interesting to look at for the last seven years and I don't see an end to that anytime soon.