Pulmonarias and brunneras will happily grow there. Hellebores are a must
Have you thought of liriope? Evergreen dark green grasslike foliage with purple blue spikes of flowers in autumn. There are variegated forms and a new white variety....white FOLIAGE.
A couple of box or similar rounded topiary shrubs would add shape. A white hydangea would sit happily there. White arum lily too. Three yellow grasses..acorus Ogon (not really a grass but looks like one) is evergreen, Bowles golden grass is pure yellow loveliness and hackonochloa is superb albeit deciduous.
There are loads of plants ...try geranium phaem. In the summer plant a few busy lizzies to give a splash of colour all summer. To keep the white theme use white new guinea types