Primula
Family: Primulaceae
Genus: Primula
Intro/Brief Description
Primula comes from the Latin prima which means first. Primula are among the first flowers to bloom in the spring. Its common name is primrose.
There are more than 500 species in this genus. The genus Primula is believed to have originated in many parts of the world including China and France. Species within the genus have originated in many parts of the world. It is a popular house and garden plant in Europe, where many of the species originated in alpine meadows. Although most Primula are perennials there are a few biennials.
Primula quickly became a favored house plant because it can be unearthed and transplanted into pots easily.
Examples
Primula auricula is 2”-8” tall. Its leaves are 2”-3” long and are paddle shaped. Flowers are 1” wide and appear in early to late spring. Zones 2-8.
Primula denticulata is known as Drumstick primrose. It is 8”-12” tall. Its leaves are 4”-6” long and sharply toothed. The flowers grow on a thick stalk. They are a cluster of lilac or white flowers. Zones 3-8.
Primula elatior is known as Oxslip. It’s 10”-12” tall. Its crinkled leaves are 8” long. It has 1” wide soft yellow flowers. With winter protection elatior will survive in zone 3. Generally, zones 4-7.
Primula japonica is known as Japanese primrose. It is 1’-2’ tall with 1’ long leaves. The leaves are shaped like a paddle; sharply toothed. Flowers are clustered, 1/2” wide, are white, pink or red, and appear in late spring and early summer. They sit upon a long, narrow stem. Japonica is not as cold hardy as other species. Zones 5-8.
Primula sieboldii is Siebold’s primrose. It’s 4”-8” tall with 2”-4” wide leaves. Siebold is a bit different from the other primulas listed. Its leaves are fuzzy, have rounded teeth along the edge, and are heart shaped. Siebold has large flowers for its small size. They’re 1-1 1/2” wide. The flowers are flat and have noticed petals.
Special Features
Primulas are undemanding plants excellent for beginners. They require little care . Some species’ leaves are edible. The smaller leaves of late winter/early spring are favored for use in salads. They have a mild flavor. Moths, butterflies and bees are welcome pollinators though Primulas are self pollinators.
Hardiness
Hardy in zones 2-8. Growers in the coldest climates should mulch well. Primula stands up to cold weather and light frost without becoming dormant. It is one of the first plants to emerge in a spring garden, usually about the same time as daffodils.
Growth Habit
Primula are spring flowers. They are non-invasive plants perfect for woodland and rock gardens. The average height of Primulas is 10”-12”. Low-growing species can be used in empty spaces to create a pretty ground cover.
Primula do well when tucked into crevices in shady rock and cottage gardens.
Bloom Time
It flowers in early spring, around the time most bulbs bloom. Primula produces seeds by mid summer. You might occasionally see small autumn blossoms but Primula usually blossom only once, in the spring.
Propagation
Primula can be seeded in autumn for spring germination. Home growers might benefit from sowing seeds in coldframes in late autumn for earlier than usual germination. Soil should be loose and well drained but able to hold enough moisture to be lightly damp.
Mother plants also generate smaller plants from their main roots. The plants can be unearthed, divided and replanted in fall. If plants are blooming in fall, wait until blooms are finished. Roots should be carefully checked for pests and disease at this time.
Transplanting
Primula should be transplanted into the ground when the soil has warmed sufficiently and there are at least two leaves on the seedling.
Soil
Primula likes moist, humus-rich soil. Prone to go dormant if the soil becomes too dry. Will grow in sandy soil if it contains enough organic matter to nourish the plant.
P. japonica and P. denticulata require wet to boggy soil.
Irrigation
Water deeply to keep soil moist at all times. Watering is best done in early morning so that water has adequate time to sink into the soil before sun and wind/breeze speed up evaporation. Primula need more water in summer than in spring and autumn.
Sunlight
Primula do well in sunlight and partial shade. In hot climates, protect from long periods of direct sunlight.
Care
Primula are undemanding and need little care. You can either deadhead after bloom to let the blooms go to seed. Seed can be collected, chilled in the fridge for 2-4 weeks, and planted. Fertilize lightly in the spring and mulch for winter protection in late fall. Worn out leaves can be trimmed with clean, sharp scissors.
Pests
Wooly aphids attack the roots of the plant. You can unearth the plant and dip the roots in a 10% alcohol/water solution to try to gain control of this pest. Vine weevils also destroy the roots of Primula. The best control for these pests is healthy soil in the proper location. Pests usually do not attack Primulas unless they are already stressed.
Mice tunneling under the snow will eat the crown of the plant. They’re difficult to trap in winter unless your Primulas are in a greenhouse. If this is the case, set traps. Birds and mice will eat the seed pods. Birds, mice, caterpillars and earwigs can cause leaf damage. They generally do not devastate plants. Birds will eat some caterpillars and earwigs will eat wooly aphids. If you feel they are truly becoming pests you can physically remove them without chemical interaction.
Disease
Botrytis and gray mold are common diseases. They can be avoided by not over watering plants in spring and autumn, by not over crowding plants, and by allowing good air circulation. Clean out dead plant matter in the fall to reduce the chance of over wintering spores of these diseases.
If botrytis and gray mold do occur they can be treated with a fungicide.
Additional Info
Evening Primrose, used by women for pre-menstrual symptoms, is not related to the Primula we commonly grow in our flower gardens. Evening Primrose is of the Onagraceae family.
There are some Primulas that have medicinal uses. Primula elatior root is used for cough, fever, insomnia and headaches.
Cowslip primulas were used to make wine. The wine was then used as a sedative. Cowslip water used to be considered good for one’s memory. It was also credited for rinsing away years of ages from one’s face.
References
Perennials A Dorling Kindersley Book
Rodale’s Illustrated Encyclopedia of Perennials
Ellen Phillips & C. Colston Burrell