Lots of non boring geraniums with bigger flowers! Try Long Acre Plants who specialise in shade lovers. Epimediums and erithroniums , lirope for starters. Euonymus fortunii will give you bright leaves all year - look at Emerald 'n Gold if you like gold ones, and there are some less bright silver ones. Heaps of ferns would do well and some are evergreen. Summer flowers are more difficult because of the shade of the tree canopy but some of the geraniums would tolerate it. Foxgloves might do, worth a try. Primroses in a spot that gets some sun for part of the day, and fibrous rooted begonias for summer bedding are very reliable whatever the weather. Look at goypedia under S for Shade. English bluebells like damp woodland and would look nice near the euonymus. Heucheras too if you watch out for slugs and vine weevil. I have just succeeded with corydalis flexuosa in damp partial shade - don't know how it would cope with the roots though.

agree with the above and corydalis thrive under my beech tree. dont forget the lamiums as there are a lot of different variegated forms in white/pink and yellow flowers.

go to S at the bottom, click and shade will appear and look at the ones suggested there.

Thanks lots of ideas there, have bought some Heucheras for at the front but then got stuck on roots

Cyclamen would also be suited to these conditions.

If it is a deciduous tree spring bulbs will also be quite happy there!