In the Book of Thomas Jesus talks about 5 trees in Paradise that do not lose their leaves despite the harsh environments of winter and summer. The evergreen tree is the only tree that comes close to that description. Here is a list of edible fruits from the Evergreen Tree. You can't easily find these fruits at the local farmers market.
http://www.wildernesscollege.com/evergreen-shrubs.html
Here is a list of several highly useful evergreen shrubs for permaculture applications:
Bamboo species (Phyllostachys spp., Pseudosasa spp., Pleioblastus spp.) – though technically a giant grass this group of plants often grows to shrub or small tree size, has edible shoots, provides building materials, thicket forming, seeds are edible
Rosemary (Rosmarinus officinalis) leaves used in cooking, beneficial insect attractor, used for soaps/shampoos, medicinal plant
Salal (Gaultheria shallon)– evergreen, edible fruit, jams/cooked fruit, hedge/thicket forming, shade tolerant
Strawberry tree (Arbutus unedo) – evergreen, fruit edible when ripe, made into wine, beneficial insect attractor, little maintenance
Elaeagnus (Elaeagnus x ebbingei) – evergreen, edible fruit raw, jam/fruit leather, cooked fruit, nitrogen-fixer, beneficial insect attractor
Oregon grape (Mahonia spp.) – edible fruit, medicinal roots, can be used as hedge
Plum yews (Cephalotaxus spp.) – evergreen, edible fruits, prefers shade or partial shade in hot climates, partial shade to more sun in cooler climates, dioecious (1 male per every 5 females is a good ratio)
Chilean guava (Myrtus ugni) – edible fruits, evergreen, leaves used in teas, little maintenance needed
New Zealand Flax (Phormium tenax) – amazing material source for basketry, paper, edible nectar and seeds, beneficial insect attractor, tolerates shade but likes sun
Tea (Camellia sinensis) – source of several different teas, fragrant flowers in fall
Evergreen Huckleberry (Vaccinium ovatum) – hedge forming, edible berries, windbreak, full sun to shade, grows tallest (up to 3 meters) in the shade, beneficial insect attractor
Ceanothus (Ceanothus spp.) – sweet smelling flowers, beneficial insect attractor, nitrogen-fixer, drought tolerant