just keeps getting better and better. While I'm not sure about his most recent edition of his book, arguably the bible of our age, but his website now offers a key to herbaceous plants. Here is an excerpt.
This coming year I'll officially have 5 different species of Solidago, hopefully 5 Aster, 2 Sunflower, and 3 Eupatorium. Ipomoea is a neat idea, but really only 5 or so are native to the North East. I'll have to look into adding a few of those. Certainly I. lacunosa or I. hederifolia might make it into my garden. Carex isn't my favorite but it seems I'll have to look into them too. Frankly though I'd rather establish a patch of Irises though. Lupinus I've tried before, but I believe my soil is just to clay like for them to establish. The Violets here were a weed well before I started gardening. Geraniums will be on the list next year for sure, maybe even a fall planting. Rudbeckia I'm taking care of in Spring for sure.
Common Name Plant Genus Butterfly/moth species supported Goldenrod Solidago 115 Asters Aster 112 Sunflower Helianthus 73 Joe pye, Boneset Eupatorium 42 Morning glory Ipomoea 39 Sedges Carex 36 Honeysuckle Lonicera 36 Lupine Lupinus 33 Violets Viola 29 Geraniums Geranium 23 Black-eyed susan Rudbeckia 17 Iris Iris 17 Evening primrose Oenothera 16 Milkweed Asclepias 12 Verbena Verbena 11 Beardtongue Penstemon 8 Phlox Phlox 8 Bee balm Monarda 7 Veronica Veronica 6 Little bluestem Schizachyrium 6 Cardinal flower Lobelia 4
Learn more about the study from which these numbers were derived or download the complete list of data from this study (an Excel spreadsheet).
So it's sounding like I'm doing things right.
There is also a list for Woody Plants as well.