Stephen Albert
Primrose is a large genus of popular garden plants. There are at least 425 species of hardy and tender perennials commonly called primroses or primulas.
Primroses are usually semi-evergreen. They produce rosettes of narrow to broadly rounded leaves and clusters of tubular, bell-shaped, or funnel-shaped flowers.
The name primrose is believed to come from the Latin primus (first); primroses are among the first flowers to bloom each year; they bloom in spring along with crocus and early tulips.
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Primroses, depending on the species or cultivar can produce single blossoms or umbels of up to 20 flowers; flowers can appear in tiers or whorls. Flowers appear above leafy rosettes; some flower on tall stems, and some are stemless. Primrose blooms in a wide array of colors—pink, red, blue, purple, and orange in many shades.
Generally, primroses grow best in shady places, humusy soil, and cool temperatures. They are used in natural and wild gardens, in rock gardens, containers, and formal bedding designs.
Get to know primrose — Primula
- Plant type: Perennial or annul
- Growing Zones and range: 5-8; grow as an annual or perennial depending on the climate; grow as an annual in Zones 3-7
- Hardiness: Varies from hardy to tender depending on species and cultivar; all types can survive to 35°F (1.7°C); few can survive temperatures of 90°F (32°C) or greater.
- Height and width: 3 to 12 inches (7.6-30cm) tall; 6 to 12 inches (15-30cm) wide
- Flowers: Flat or ruffled flowers about 1 inch (2.5cm) wide in small stemless clusters or in found or elongated racemes on tall leafless stems depending on the variety.
- Flower color: All colors in pastels and brilliant hues
- Bloom time: Early spring until early summer in most regions; some rebloom in autumn; winter blooms in mild winter regions; bloom time is about 6 weeks
- Uses: Winter and early spring bedding
- Common name: Primrose
- Botanical name: Primula
- Family: Primulaceae
Where to plant primrose — Primula
- Plant primroses in full sun in Zones 3-6; plant in light shade in Zones 7-10.
- Grow primroses in humus-rich, moisture-retentive but well-drained soil.
- Primroses prefer a soil pH of 6 to 8, depending on the variety.
When to plant primrose — Primula
- Set primroses in the garden when the soil is workable in spring. In mild-winter regions set plants in the garden in winter.
- Plant in early spring in Zones 3-7. Plant in late autumn in Zones 8-10 for winter bloom.
- Start seed indoors; seeds germinate in 3 to 6 weeks.
- If seeds do not germinate, put seeds in the freezer (still planted) for 4 to 8 weeks, then place them in a warm outdoors.
Planting and spacing primrose — Primula
- Sow seeds indoors by pressing the seed into a seed starting mix; do not cover the seed.
- Cover the seed starting container with glass or plastic and keep seeds at 65° to 70°F (18°-21°C) until seeds germinate. Do not give seeds direct sunlight; give them bright light.
- Sow seed outdoors in nursery beds in warm spring weather (around 70°F/21°C). Sow seed outdoors less than 1/8 inch deep and about 2 inches (5cm) apart.
- Thin seedlings to their permanent spacing when they are about 1 inch (2.5cm) wide.
- Set plants outdoors in spring after all danger of frost has passed; harden off plants in the shade several days before planting out.
- Space primroses 8 to 12 inches (20-30cm) apart.
How to water and feed primrose — Primula
- Keep the soil evenly moist but not wet. Water primroses regularly during dry spells. Do not let primrose dry out.
- Fertilize primroses with a slow-release, all-purpose fertilizer added to the soil at planting time.
Primrose care
- Mulch around primroses with aged compost to conserve soil moisture.
- Mulch primroses in summer with 2 inches (5cm) of peat moss or aged compost.
- Remove spent blossoms to encourage new blooms.
- Discard spent plants when hot weather arrives.
- Protect primroses in winter by mulching around crowns with 2 inches (5cm) of peat moss or aged compost. Pull back the mulch in spring after the danger or frost has passed.
Growing primroses as a houseplant
- Indoors primrose prefers a spot where the temperature is cool, light is bright, and humidity is high.
- Plant in rich, soilless medium and keep it evenly moist.
- Fertilize every two weeks in spring, summer, and fall.
- Plants can be moved outdoors into a shaded garden after they bloom.
Primose pests and diseases
- Primroses are susceptible to attack by aphids, spider mites, mealybugs, whiteflies, weevils, and slugs.
- Spray plants infested with insects with insecticidal soap. Deter slugs by sprinkling diatomaceous earth around plants.
- Diseases that attack primrose include gray mold, root rot, crown rot, rust, and leaf spots.
- Avoid wetting foliage and flowers; gray mold and rust can attack plants with wet foliage and flowers.
Primrose propagation
- Primula malacoides: Seeds germinate in 7 to 10 days at 60° to 65°F (15-18°C). Plants will be large enough for transplanting in 18 to 25 days. Flowers usually appear 12 to 13 weeks after sowing.
- Primula obconica: Seeds germinate in 7 to 14 days at 72° to 74°F (22-23°C). Plants will be large enough for transplanting in 18 to 25 days. Flowers usually appear 18 to 20 weeks after sowing.
- Primula x polyantha: Seeds germinate in 7 to 15 days at 60° to 65°F (15-18°C). Plants will be large enough for transplanting in 25 to 35 days. Flowers usually appear 20 to 25 weeks after sowing.
- Primula vulgaris: Seeds germinate in 8 to 12 days at 62° to 66°F (17-19°C). Plants will be large enough for transplanting in 22 to 35 days. Flowers usually appear 17 to 20 weeks after sowing.
Primrose species
- Primula acaulis, English primrose, same as Primrose vulgaris, see below.
- P. alpicoia, moonlight primrose. Grows to 20 inches tall and 12 inches wide; wrinkled medium green leaves and clusters of yellow sometimes white or purple bell-shaped flowers.
- P. auricula, Auricula. Hardy perennial with vivid flowers that may include contrasting zones; grows to 8 inches (20cm) tall; blooms in early spring. Zones 3-8.
- P. denticulata, Himalayan primrose, drumstick primrose. Perennial bears clusters of pink, lilac, or white flowers with yellow eyes to 2 inches (5cm) across on 12-inch (30cm) stems; prefers wet zones; grows best in Zones 3-8.
- P, beesiana grows to 24 inches tall and wide; leaves to 14 inches long; bears tired blossoms with 2 to 8 dense whorls per stem; flowers are usually reddish-purple with yellow eye; need deep watering,
- P. bulleyana grows to 24 inches tall and wide; blooms mid to late spring; tiered flowers with 5 to 7 whorls pr some; blooms are bright yellow, opening from orange buds.
- P. denticulata, drumstick primrose, grows to 12 inches tall and wide; spoon-shaped, medium-green leaves; dense ball-shaped flowers on stout stems in early spring; colors from blue-violet to purple, also pinkish lavender and white.
- P. elatior, oxlip primrose. Evergreen to semi-evergreen species blooms early to mid spring dainty clusters of tubular yellow flowers. Zones 4-8.
- P. florindae, grows to 3 feet tall and 2 feet wide; yellow bell-shaped, nodding flowers in clusters; long-stemmed, medium green leaves; hybrid varieties bloom in red, orange, and yellow; flowers lates in spring to summer; ill grow in a few inches of water.
- P. japonica, Japanese primrose. Perennial species in Zones 5-8; red, white, or pink flowers on ball-shaped umbels that open in tiers or whorls on 12 to 24 inch (30-61cm) stems; blooms in late spring; foliage disappears in late summer, fall, and winter; pre-chill seeds before planting; naturalizes well in moist, boggy soil. This is a favorite of gardeners because it is easy to grow.
- P. juliae, Juliana primrose, grows just 3 to 4 inches high and 10 inches wide; magenta, yellow-eyed flowers borne singly on long stak in spring; ‘Wanda’ is a white-flowered old-time variety.
- P. malacoides, Fairy primrose. Tender annual with frilly flowers; blooms in spring; blooms are pink, white, or violet; flowers appear above attractive leaf rosettes; start plants indoors in winter for blooms the following spring and summer.
- P. obconica, German primrose. Tender perennial grows 9 to 16 inches (22-40cm) tall with tiers of whorled, 1- to 2-inch (2.5-5cm) wide flowers sometimes with frilled petal edges; flowers come in shades of pink, red, lilac-blue, and white. Touching foliage can cause a skin rash.
- P. x polyantha, Polyanthus primrose. This is a group of hybrids, Popular polyanthus hybrid primroses, crosses between very hardy primroses; hardy in Zones 3-8; blooms in spring at the same time as daffodils, earlier indoors; prefers humus-rich soil. Plants grow 8- to 12-inches (20-30cm) wide, rosettes of evergreen to semi-evergreen, rough-textured leaves. Clusters of 1- to 2-inch (2.5-5cm) wide flowers in a wide range of colors including yellow, red, orange, violet-blue, white, and pink, sometimes with yellow eyes.
- P. prolifera (P. helodoxa) grows 2 to 3 feet tall and 2 feet wide; tiered blossoms with up to 7 whorls per stem; fragrant, light to bright yellow inch-wide flowers; blooms late spring into summer.
- P. pulverulenta grows 3 feet tall and 2 feet wide; wrinkled leaves; tiered blossoms with several whorls per stem; blooms red to purple with purple eye. Bartley hybrids have flowers in pink and salmon hues.
- P. sieboldii, Siebold primrose. Clusters of delicate, lacy-looking 1-inch-wide flowers on 12-inch (30cm) stems; flower colors are pale pink, rose, white, pale purple, and purple-red. Zone 3-8.
- P. sinensis, Chinese primrose. Grows to 12 inches tall; hearts-shaped, lobed, hairy leaves; flowers are all colors; ‘Filicifolia’ has crisped leaves; ‘Fimbriata’ has fringed flowers; ‘Stellata’ has star-shaped double flowers.
- P. x tommasinii grow 6 to 12 inches tall and 18 inches wide; green tongue-shaped leaves; a single flower emerges from the center; types include Hose-in-hose and You and Me series; flower colors are yellow, cream, maroon, red, rose, white, purple, apricot, and blue.
- P. veris, English cowslip. Bright yellow in the wild with hybrids in many other colors; grows to 8 inches (20cm) tall; hardy in cool, shady gardens in Zones 3-8. ‘Grandiflora’ is used in the names of large-flowered cultivars.
- P. vialil (P. littoniana) grows 1 to 2 feet tall and 1 foot wide; oblong, irregularly toothed leaves; dense , narrow spikes of fragrant flower to 5 inches; blooms late spring into early summer; flowers are violet-blue, opening from red buds.
- P. vulgaris (synonm P. acaulis), English primrose. Very popular primrose bloom in early spring; hardy if grown in cool, moist shade in Zones 3-8; flowers available in bright colors; foliage remains partly evergreen in winter; produces 6- to 8-inch (15-20cm) wide rosettes of evergreen to semi-evergreen 9- to 10-inch (23-25cm) long leaves and clusters of 1-inch (2.5cm) wide, pale yellow flowers in clusters. Cultivars are available with single or double flowers in white, orange, magenta, purple-pink, and yellow.
Primrose Frequently Asked Questions
Q: What primroses can I grow indoors in winter?
A: Chinese primrose, Primula sinensis, can be grown indoors. Fairy primrose, P. malacoides, has small, violet blossoms throughout winter grown indoors. Giant fringed primrose, P. grandiflora fimbriata can be grown indoors as can P. obconica. Keep these primroses in a cool window with a dish of water nearby or provide humidity.
Q: What can I do to make my primrose bloom indoors?
A: Indoor primroses like a cool temperature, bright light, and high humidity. Fertilize plants every two weeks in spring, summer, and fall. Nip off spent blooms. Plants are usually discarded after the flowers have faded, but they can be moved into a shaded outdoor garden and they may bloom again.
Also of interest:
How to Grow to Grow English Primrose–Primula vulgaris
How to Grow Polyanthus Primrose
