Crown jewels of the cool season: primroses shine in the garden or in containers, from winter into spring

Sunset, Jan, 1997 by Jim McCausland

Like bright jewels spilled over the dark earth, primroses add sparkle to the winter garden. The flowers come in shades of amethyst, citrine, garnet, sapphire, and pink tourmaline; some are even edged with gold or silver. Yet for all their delicate beauty, not even frost and rain can take the luster off these garden gems.

Most gardeners grow primroses from plants, not seeds. In mild-winter areas of California and the Southwest, the plants are on the market from October through early spring. Early in the season, you can buy them in flats, six-packs, or 4-inch pots.

In mild parts of the Pacific Northwest, primroses show up mostly in 4-inch pots from New Year's through early spring. In snowy-winter areas, plants appear in late February or March.

As bedding plants or in containers, primroses look great. Regular feeding promotes bloom. Bedding plants do best with an application of complete, controlled-release fertilizer every three months or so. For container plants, apply a complete, half-strength liquid fertilizer twice a month.

THE STARS OF PRIMROSE LANE

Plants are often sold simply as English primroses, fairy primroses, or obconicas. English types take more sun (in warmer climates, give them filtered sun in the hottest part of the day); fairy primroses and obconicas do best in light shade. The chart on page 52 shows you which kinds grow best in your Sunset climate zone.

English types have outsold other primroses for decades, and their flowers come in a wide range of brighter colors than you'll find in fairy primroses or obconicas. English primroses come in two types: acaulis and polyanthus.

Acaulis primroses usually have just one flower per stem, and the stems are only about 3 inches long. Breeders are concentrating on acaulis types, and their work shows: the flowers are very large, and the colors are exquisite. There are many hues of burgundy, red, pink, bronze, brown, yellow, apricot, white, and blue.

In the landscape, acaulis primroses tend to make a big splash of bloom early, then follow with more sporadic flowers throughout the season. They'd bloom more heavily and longer if it weren't for a rain-induced mold called botrytis. You can limit it by faithfully deadheading faded blooms.

Because of the botrytis problem and because acaulis blooms aren't tall enough to be seen easily from a distance, we recommend them for container plantings. Given protection from rain, they're perfect in wide bulb pots and front porch flower boxes. They also make good indoor plants if you can give them plenty of light.

Polyanthus hybrids flower on 8-inch stems and thrive just about anywhere. Look for Concorde, Pacific Giant, or Santa Barbara hybrids. The color range is almost unlimited.

Because polyanthus bloom stalks stand tall in the landscape, they show up well in flower beds.

Fairy primrose (Primula malacoides), a frost-tender species, likes mild-winter climates. It bears delicate whorls of bloom on 15-inch stems. The widely available Prima series has especially clear colors.

Because of fairy primrose's susceptibility to snails, slugs, and frost (28 [degrees] is its lower limit), the popularity of this plant is declining in parts of the West.

P. obconica, sometimes called German primrose, is a rising star among the primroses sold in mild-winter parts of Arizona, California, and Texas. Sunset's head gardener, Rick LaFrentz, raves about this plant. "Of all the primulas we've grown, the obconicas are the most resistant to snails and slugs, and flower the longest. They start in October and bloom until we dig them up in May."

The obconicas come mostly in white and pastel shades of pink, salmon, magenta, orange, and blue.

Until recently, growers didn't like obconicas because their leaves give some people an itchy rash. But Goldsmith Seeds, a wholesale grower in Gilroy, California, came up with Libre, a nonallergenic obconica series that's free of primin (an alkaloid); these plants are easier to handle.

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