Firstly it must be understood that, Fuchsias classed and sold as hardy are in fact only hardy enough to withstand a winter outside, if they are established in the garden soil and some have higher degrees of hardiness than others.
If you plant a hardy fuchsia in a pot, it is worth remembering that you should not keep this outside during the winter if it's to survive. This is because it is only the rootball of the fuchsia that is hardy. If left in a pot, the frost can attack the roots from the sides and the plant will die. In mild winters or milder areas hardy fuchsias in large tubs may survive, but plants in small pots, baskets or grown as standards should be treated as half hardy in all areas of Scotland and cultured as described in the fuchsia help pages.
There is also a myth that hardy fuchsias only have small flowers but, in fact, there are many varieties that have large double or single flowers that can be full of colour from June to September. Garden News for example, has striking double flowers with magenta rose corolla and rose pink sepals.
Success in cultivating winter-hardy fuchsias depends largely on preparing the plants and caring for them. The ideal time of year to plant a hardy Fuchsia is Spring soon after the last frost, this gives the plant all summer to become established. The growing medium must be free draining and should be rich in humus with plenty of nutrients. Plant the roots of young or mature plants in the ground slightly deeper than they were in the pot, to provide extra protection during winter.
All Fuchsias do need light in order to grow, and whilst they will tolerate full sun, and partial shade, deep shade is to be avoided. Ensure after planting that the plant does not dry out, certainly if there is not enough rain. Once the plant starts to grow strongly, a top dressing of fertilizer can be added.
Do not cut fuchsias back in the autumn. The branches will give extra protection to the parts of the plant that are below ground. Hardy fuchsias should also be left in situ over the winter. In very cold areas, cover the base with bracken, or mulch. In the spring, prune them down to where new buds are developing.
Finally don't be disheartened if you loose one or two, ... we all do from time to time.
Below we've tried to provide a bit more detail on what cultivars are classed hardy.
British Fuchsia Society
Hardy List for the Showbench
The table below is a list of cultivars provided by the BFS, which the BFS accept as hardy for the purposes of exhibition.