Hellebores are among my favourite plants. They like humusy soil (i.e., lots of organic matter) and can't be planted too deep or too close to the surface (so make sure the crown is just below surface level). Give them a deep water and spread compost around but not so it touches the plant. The new cultivars can take a lot more sun than the plant's more traditional species, so be careful to read the tags but feel free to use almost everywhere. And if they stop growing, it's because it's too humid. Don't worry, though: They'll start again when things cool down.