Around here, junipers tend to grow in dry alkaline soil with a high clay/silt content. They grow in the drylands, so I presume that means they don't compete well with deciduous trees that thrive in somewhat moister areas.
Juniper Habitat:
I allow Logans to sprawl... I run the tiller/mower through the thicket to make walkways. I take starts out of the walkways. I walk through the garden and trample the walkways. If I get around to it, I take the loppers out and cut them off at about the point where they start bending over. At a nice height for picking.
Grapes, squash, and cucumbers are my climbing plants...
I love growing sunroots in a perennial bed. The size and quality of the tubers suffers if they are not dug...
Sunroots: