Myriam, I think the existing checkbox "Suitable for xeriscaping" already covers drought-resistant plants, and perhaps we could assume that plants thriving in shade or dappled shade are suitable for woodland gardens, but I do agree that we need a category "suitable for bog gardening." I've done a lot of searching on the Web for bog plants through the years and it would be nice to mark all of them as such in our database.
With the combination of "suitable for xeriscaping" and "suitable for bog gardening" categories, we could safely assume that anything not included in either of those categories has average moisture needs.