Overview and Description of Primrose Plants
Primroses are woodland flowers that come in vivid colors you might not expect from spring blooming perennial flowers. Unlike the subtle pastels associated with spring, primroses shout out in bold yellows, reds, pinks and blues. In many species, the flowers are fragrant and they are all popular with pollinators and butterflies.
- Foliage: Primrose leaves form a basal rosette and remain evergreen, although they get rather disheveled in cold, snowy climates.The leaves can be smooth, wrinkled, thick, narrow, fuzzy and just about anything in between
- Flowers: There's a lot of variety in primrose flowers. The candelabras hold their flowers high above the foliage, on long stalks. Some varieties have umbrella-shaped clusters of flowers. Other primulas have one flower per stem, and the stems create clusters of flowers that skim the rosette of leaves. There are also pin-eyed flowers where the stigma can be seen in the center of the petals, resembling a pin head. And thrum-eyed flowers where the stigma only reaches half way up the flower tube, creating a yellow/orange central disk.
You can grow primrose in USDA Hardiness Zones 3 - 9. Most varieties of primrose are extremely hardy and adaptable, however the primrose plants forced early in the season as gift plants don't seem to have the strength to survive outdoors.
Primrose thrive in partial shade and look perfectly at home when planted in large swaths near a tree.
If they have to, they can tolerate full sun, but they'll need more frequent watering to remain cool and moist.
The primrose plants themselves remain low, but the flower stalks can double their height. Most varieties fall between 6 - 30 inches tall x 8 - 20 inches wide.
Primrose flowers have a long season of bloom, staring in early to mid-spring (Primula is from the Latin for early) and continuing for 6 weeks or more, depending on the temperature and weather.
Garden Design with Primroses
Primroses will brighten any shady corner. They look especially good massed under a tree or in a natural setting like a rocky cliff or woodland area. Primroses are a good choice for the north side of a house or as an early spring ground cover under foundation shrubs.
Suggested Primrose Varieties
Primula denticulata (Drumstick Primrose) - These grow about 1 ft. high with a clustered ball of flowers atop a sturdy, upright stem. Good from seed.
Primula x polyantha (Modern hybrids) - There is a lot of variety in this grouping, but most of what you will find in local garden centers would be included here. Easy to grow.
Growing and Caring for Primrose Plants
Soil: As woodland plants, primrose prefer a moist soil with a slightly acidic soil pH. They also welcome copious amounts of organic matter. While primrose plants like moist soil, most varieties do not like to sit in wet soil and need the well draining texture a rich, organic soil can provide. (Both Primula japonica and Primula denticulata can handle wet feet.)
Starting Plants from Seed: Primroses are not suitable for USDA Zones above 9 and up because they require a winter chill to survive and bloom.
When starting plants from seed, a temperature between 40 - 50 degrees F. Is required from sowing to first bloom, which is next to impossible to attain indoors. You'd be better off allowing the plants to self-sow.
Dividing Primrose: It's easy enough to lift and divide primrose plants, after flowering. This is the best way to multiply your batch, since it guarantees you can maintain specific cultivars.
Once established, primroses need very little care, other than occasionally dividing the expanding clumps. Just be sure they get regular water, which shouldn't be a problem in spring, and some shade during the hottest hours of the day. If you plant them in a suitable site, you should have not problems. They don't even require winter protection.
Pests and Problems of Primroses
Primroses are generally pest free.
Occasionally spider mites can be a problem, especially when the plants are heat stressed.
Primroses are also prone to a leaf spot disease, which manifests as brown lesions on yellowing leaves. Remove infected leaves and make sure your plants are getting adequate air circulation.
Tip: To guarantee you get the flower color and style you want, buy your primroses while they are in bloom. They should still remain in bloom for several weeks, when you take them home and plant them.