Some first-year-flowering border perennials
Same-year blooming depends on early sowing, with a bit of heat, such as on a warm window sill.
Transfer seedlings to a cold greenhouse and pot as soon as they are large enough. Plant out in May.
Achillea millefolium (yarrow); Agastache, several (Mexican hyssop); Catananche caerulea (cupid's dart); Coreopsis, several (tickseed); Digitalis Camelot series (foxglove); Gaillardia, several (blanket flower); Gaura lindheimeri; Geum, several; Echinacea, some varieties (cone flower); Lupinus, Russell strains (lupin); Lychnis chalcedonica,
L. x arkwrightii; Malva moschata (musk mallow); Nepeta, several (catmint); Oenothera, several (evening primrose); Salvia nemorosa, S. pratensis (sage); Verbascum phoeniceum, V. blattaria, Verbena bonariensis, V. hastata