A potpourri (below) of primrose/cowslip/Primula species information as a supplement to other articles.
A plant-based page rather than our usual topic-based page. It's a pivot point, one list of links to ours and others' articles that involve Primulas.
They're called primrose, primula, cowslip, or oxlip, with various modifiers (purple, spring-, English-, Turkish- etc.) The prim in both common- and scientific name refers to prime, first -- a nod to their early blooming time.
Excluded here, the plants in genus Oenethera that are called primrose -- day primrose, evening primrose, sundrops primrose, etc.
The Primula primroses are spring blooming cuties in every color, the flowers held close like a posey against evergreen foliage as in P. vulgaris or held high as on candleabra type (P. japonica is one). All they need is moist, well drained soil, a few hours of sun each day, a reasonably long cool spring and perhaps some slug protection.
Primula polyanthus, perhaps the most commonly sold hybrid primrose, is supposed to be hardy only to zone 7 but we see it perennialize often enough in zone 5 to be pretty sure that there must be quite a few zone 4 P. vulgaris genes in some varieties. That, or it's not cold but dry summers or exposed winters that kill P. polyanthus. Where they persist over winter we can divide these plants (below) repeatedly to create the proverbial primrose path.
Various Primulas hold their flowers high and are called candleabra- and drumstick primroses. Hardy species (zone 4) in the group are P. beesiana, P. japonica (below), and P. denticulata. Where they're well sited they can become impressively large clumps and the flower stalks may be 24" tall.