As for fertility, all of our hellebores are fertilized with an organic slow release blend in the spring with everything else in the garden. For the lazy gardeners, however I have seen spectacular gardens of hellebores that have never seen a drop of fertilizer. A true testimonial for the durability of hellebores are those growing at the old Raleigh garden of NC's famed garden writer Elizabeth Lawrence. Her Raleigh home, from which she moved in the 1940's is still filled with wonderful clumps of Helleborus orientalis hybrids. As for drought and neglect tolerance, that story speaks for itself.
Hellebores are sensitive, however to too poor drainage and too much moisture.
Although H. orientalis hybrids are very forgiving, many of the other species are not so, and will quickly bite the dust if planted in a soggy site. The caulescent species include H. argutifolius, H. foetidus, and H. lividus. The acaulescent species include H. orientalis, H. niger, H. purpurascens, H. viridis, H. atrorubens, and all others. The most commonly known of the acaulescent species is Helleborus orientalis, the Lenten Rose. Actually what everyone grows in their gardens are not really H. orientalis, but hybrids involving H. orientalis.