Lol, just about all of the above mentioned plants are botanical perennials, though many are used AS annuals. I think that larkspur is a true annual. Many of our most popular 'annuals' are tender herbaceous perennials, which means that in colder parts of the world, they are killed by freezing temperatures and do not return though many of them reseed. That behavior still doesn't make them annuals in the botanical sense of the word. It makes them tender perennials. ;-) We'll see them labeled as annuals in catalogs and seed packets and on-line because that's how the vast majority of us use them. The annuals in your data base are perennials, with the exception of the genus Linaria, in which there are true annuals and perennials. Canna, for example, is a rhizomatous plant. It's not hardy where you are, but actually quite long lived warmer temperate zones. I'm only being a stickler on this because you seem to be taking great care in compiling your database. I know that you want it to be accurate. And you really couldn't be faulted by clumping many of these plants together because they are used AS annuals. You should do a search on true annuals so that you can add to your list. Zinnias and marigolds qualify. If you are collecting information on other categories of plants besides those known for their flowers, there are lots of grasses and food crops that are annuals, too.

I checked Hazzard's Greenhouse seed listing. They sell quite a few heuchera cultivar seeds but neither Georgia Peach nor Peach Flambe are listed on their website. Could be they're still too new for seeds to be commercially available but I think those two have been around a few seasons. Good luck!

One of the problems with using common names (Japanese Silver Grass) for plants is they are often catch-alls for lots of different cultivars. Japanese Silver Grass is a catch-all name for Miscanthus sinensis, and there's a wide variety of them out there in cultivation. In general, they are hardy to your zone, and most will set viable seed. However, seed from the cultivars which differ most dramatically from the species, like dwarf, variegated and so forth cultivars, are least likely to come true from seed. If you get good ripe seed, and get it to germinate, your chances of getting those unusual characteristics are slim, but you will get plants close to the species. There are a few named cultivars which are commonly grown from seed, and while they don't necessarily yield exact duplicates of the parent plants, they will grow into nice plants. M.s. 'New Hybrids,' 'Early Hybrids' and 'Late Hybrids' are the most recent additions to this group. Being hybrids, you can never tell just what you'll get from the seed, but they germinate well, and grow into nice plants. M.s. 'Gracillimus' is another variety which is often grown from seed, and has led to many new and exciting cultivars in Miscanthus breeding.

I'll knock this down because.... Since I last posted my question I've been reading up. In case anyone else would like an answer, KMOTGG is open-pollinated and will come true from seed. So it's worth it to collect the seeds for new plants. As far as I can tell, both the asters I asked about are hybrids, so they won't come true from seed. So while I might get some asters, I won't know how they'll look until I see them flower. If I want the same plants, it's better to divide the ones I'm already growing.