Shade-loving plants such as tuberous begonia, fuchsia, and rhododendron have shallow root systems. If exposed to hot sun for long, they lose water faster than they can absorb it from the soil--and they sunburn, wilt, or wither as a result. To grow these plants successfully, you'll need to hold direct sun to a minimum and keep humidity high. If you live near the ocean, the cloud cover and natural humidity may do your work for you. Gardeners living farther inland should locate their shade plants under the shelter of high-branching trees, beneath lath structures or shade cloth, or on the north or east side of a building, fence, or wall.
In any area--whether coastal or inland--it's important to shield shade-loving plants from steady winds. Fences, louvers, and windbreak plantings all do the job nicely.
To provide the necessary high humidity, water often and be sure to mulch your plantings; a coarse, moist mulch releases a considerable amount of water into the air. On days when temperatures are especially high or humidity especially low, water with particular diligence and mist the plants' foliage as well; a drip irrigation system with mister-type emitters can help you here.