Vinca minor and heuchera
Can I plant young heuchera and vinca minor bare root plugs in the same area and not have the vinca choke out the heuchera over time? The bed is 50% dense shade and 50% partial shade. If I need to plant them separately, will a wide (how wide?) mulch strip keep the vinca contained? I have read about both plants a lot, though I've never grown them.
Heuchera has a growth habit that radiates from a rosette shaped basal clump. So it stays relatively contained within a certain area. It will prefer the partial shade of your site.
Vinca minor is a spreading plant which sends out long shoots which then root and form new plants. Over time, if not controlled, the Vinca minor will overtake your Heuchera. Mulch by itself will not contain shoots. Because the shoots are long, they can leap over barriers such as metal edging.
Both plants can coexist as long as you are vigilant in controlling the spread of the Vinca minor.