The only groundcovers I feel comfortable allowing to grow right up to my hosta crowns are Creeping Jenny and low-growing sedums.

I have had periwinkle attempt to insidiously strangle hostas when I'm not looking, so I clear a circle and mulch to the drip line of the hostas that live in the periwinkle neighborhood.

I haven't noted any malicious intent from lamium, ajuga, violas or pachysandra, but why take the chance? I keep the immediate areas clear in those beds, too. You also have to consider the mature height of the groundcover and plant a hosta that will rise above and not appear to be drowning in a sea of plants.

The hostas are the star players in my gardens, the groundcovers secondary.

I have a gorgeous bed of sweet woodruff in front of a clump of variegated hosta (large green leaves with white borders). Both the hosta and the sweet woodruff are doing great.