I answered the same question earlier today - so I've copied my suggestions. You need to bear in mind that conifers suck the nutrients out of the ground, and leave the soil dry and probably full of roots.

Try Symphytum 'Goldsmith' or S.'Hidcote Blue', Vinca difformis, Hedera (you can get pretty variegated forms), and Geranium macrorrhizum. They are all spreaders, so you may have to keep them under control.

I built a raised bed under a fir tree, and filled with quality soil - see my photos. I have several shade loving plants - but I have to water them regularly.