I'm coming in rather late to this discussion but Leptinella gruveri would not be my first choice for a groundcover in that much shade. And I think any sources that recommend it for full shade have maybe not really grown it under those conditions before. If you research locations where this plant is native, it lists subalpine grassland and rocky areas.....not what one typically considers to be very shady locations. And throughout all my time in the nursery industry (including for a wholesale grower of groundcovers), this plant - all the species of Leptinella - were listed as a full sun to part shade groundcover. And that partial shade designation was for those growing it in a hot summer climate. If you Google images of this plant, you will find the best examples, the densest carpets of it, in very open, not very shady situations. Here, it grows happily and quite densely in full sun. In addition to more light, it typically prefers a rich, well draining, slightly acidic soil and even moisture. It dislikes drying out. Based just on the photos displayed above, I'd guess this is just not a very welcoming spot for this particular groundcover.

I'm interested in possibly replacing our back lawn with Miniature Brass Buttons. According to the Stepables website it's supposed to take heavy traffic. Have you found this to be true? Does it block out the weeds? What does it feel like for people who actually walk on it? How often do you have to do any mainteance with it? Any real-life perspective on this plant as a groundcover would be greatly appreciated.

I lost Wooly Thyme in a dry area, and Brass Buttons is struggling there too. Blue Star Creeper, Isotoma, does very well, though, and spreads rapidly. My New Zealand Burr, Acaena, also spreads well but makes burrs so you might not like that aspect of them. Actually the blue-green form makes burrs but I haven't seen any on the purple forum, inermis purpurea. I tried to search for them on the Stepables site and they didn't come up, perhaps Stepables doesn't sell them anymore.

Here's what Googling came up with http://www.hgtv.com/hgtv/gardening/article/0,1785,HGTV_3546_1371942,00.html http://greenwoodnursery.com/page.cfm/10406 Hope this helps. :) Tanya