Plant primroses in rich, slightly acidic soil, fortified with plenty of organic matter and kept moist during the spring growth spurt and bloom periods. Though they’ll survive with less water in summer and fall, polyantha primroses do best in moist soil. You can help keep the ground moist and cool by mulching well with compost or another organic material. Divide crowded clumps after flowering in spring or in early autumn. If you notice snail or slug damage, go out on an early-morning foray and pluck off these munching pests. (Also see page 114.)
Polyantha primroses are a popular group of hybrids that have evolved from repeated crossings of several genera, including P. elatior, P. juliae, and P. vulgaris (the English primrose). They form tight, low clumps of crinkled and deeply veined leaves; many are evergreen but others die back in winter. All are glorious in full bloom, lighting up shadowy areas with their cheery flower clusters in radiant colors. Few other plants embody the essence of spring with the verve and gaiety of the polyantha primrose.
ZONES: 5–8
BLOOM TIME: Early to late spring
LIGHT: Filtered shade
HEIGHT: 6–12 inches
INTEREST: Multicolored blossoms with contrasting yellow eyes; easy to grow in moist, semi-shaded locations
The polyanthas are perfect primroses for beds in semishaded lawns, glorious either in formal masses or in small colonies. They tuck easily into rock gardens and are ideal in wide, shallow pots on covered patios and decks. The polyanthas are excellent edging plants along perennial borders in part sun, bursting into flower while late bloomers are just getting started with spring growth. When background plants mature later in the season, they shield the primroses from harsh summer sun.