What cottage garden perennials will reseed (like black-eyed susans)?
* Echinacea and gaillardia reseed in my garden.
* Dianthus barbatus (Sweet William) reseeds and acts as a biennial, perennial or annual, depending on the season and other variables.
* Black Eyed Susans are annuals in my garden.
Foxglove and Hollyhocks which are considered biennials but act as perennials in my gardens. Malva sylvestris(sp), violas which are shortlived perennials, an oldfashioned petunia, ruellia, Formosa lily, shasta daisies, all the coneflowers, rudbeckias and gillardias, columbine. I am sure they are more....
Foxgloves, Lady's Mantle, Euphorbia, Lithadora, Welsh Poppies, Campanula, Columbine, Violets, Geraniums, Ornamental Grasses, Astrantia, Hellabore and I'm sure there are more, just can't think what at the moment.
Platycodon (Balloon Flowers) reseed. Good multipliers that you can easily divide in time - Asiatic and Oriental lilies, daylilies, tall garden phlox, Siberian Iris.
These freely re-seed for me:
Salvias ( all varieties)
I don't know what zone you are in, but these all re-seed for me in zone 8.
These are the easy ones for me:
Scabiosa especially the yellow
Chinese Forget Me Not
In my garden:
Rudbeckia goldsturm, hirta, laciniata, and I'm sure many other ruds
Chives, and other alliums
and many others...
These are self seeders for me:
Rudbeckias (both a and p)
verbena bonariensis (tender perennial)
salvias (annual and perennial)
Ageratum (Leilani I now have both blue and white)(a)
oriental poppies (p)
garden heliotrope (valerian)
I included the annuals because they self-seed so well they act like a perennial....I don't have to replant.
Ones that haven't been mentioned yet (I think) that re-seed for me:
Potentilla / cinquefoil (perennial type, not shrub)
Blue flax / linum perenne