Japanese Primrose
Primula japonica

Family: Primulaceae
Genus: Primula (PRIM-yew-luh) (Info)
Species: japonica (juh-PON-ih-kuh) (Info)

Category:

Alpines and Rock Gardens

Perennials

Height:

18-24 in. (45-60 cm)

Spacing:

15-18 in. (38-45 cm)

Hardiness:

USDA Zone 3a: to -39.9 C (-40 F)

USDA Zone 3b: to -37.2 C (-35 F)

USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

Sun Exposure:

Light Shade

Danger:

Seed is poisonous if ingested

Handling plant may cause skin irritation or allergic reaction

Bloom Color:

Pink

Red

Purple

White/Near White

Bloom Time:

Late Spring/Early Summer

Foliage:

Deciduous

Other details:

Requires consistently moist soil; do not let dry out between waterings

Soil pH requirements:

5.6 to 6.0 (acidic)

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

Patent Information:

Non-patented

Propagation Methods:

By dividing the rootball

From seed; winter sow in vented containers, coldframe or unheated greenhouse

From seed; sow indoors before last frost

Seed Collecting:

Allow pods to dry on plant; break open to collect seeds

Regional

This plant has been said to grow in the following regions:

Juneau, Alaska

Grayslake, Illinois

Mount Prospect, Illinois

Winnetka, Illinois

South China, Maine

Littleton, Massachusetts

Minneapolis, Minnesota

Saint Paul, Minnesota

Hilton, New York

Ithaca, New York

Hendersonville, North Carolina

Glouster, Ohio

Molalla, Oregon

Sherwood, Oregon

Allentown, Pennsylvania

Wilkes Barre, Pennsylvania

show all

Gardeners' Notes:

3
positives
2
neutrals
0
negatives
RatingContent
Positive

On Feb 19, 2014, wakingdream from Allentown, PA wrote:

I have grown a dark pink Primula for about 6 years. Placement is on the shaded north side of the house, getting a bit of early morning sun, and near a gutter runoff which keeps the area moist. I collected seeds in late summer, stored them dark-dry-cool and planted them in Winter Sowing Jugs the following February. I was abundantly rewarded with over 100 seedlings inside a plastic milk jug. I separated them out in groups of 2 and 3 in 3" pots, losing a few in the process of course, but upsizing was necessary. I transplanted the potted specimens in fall.They are currently under about 3 feet of snow, placed in an empty vegetable bed until spring when I will offer them to other gardeners at my spring plant sale. Very rewarding to be able to propagate the Primula with Winter Sowing.

Neutral

On Jan 29, 2007, bluespiral from (Zone 7a) wrote:

Following are germination details for this plant:

1) Sow @ 18-22*C [~64-71*F] for 2-4 wks; then move to -4 to 4*C [24-39*F] for 4-6 wks; then move to 5-12*C [41-53*F] for germination.

2) Sow at 4*C [~40*F] for 3 months, then place at 20*C [~70*F] for 3 months.

3) from the 2nd edition of Norman C. Deno's book, Seed Germination Theory and Practice -

-- Deno found that fresh seed germinated best at 70*F within 2 - 4 days (compare to Clothier in #1)

-- However, he found that seed dry-stored at 70*F germinated better when sowed first at 40*F for 3 months & then moved to 70*F for 3 months (compare to #2). Seed dry-stored for less than 6 months did worse than that stored at 6 month. Seed dry-stored a... read more

Positive

On Feb 11, 2005, DonnaMack from Elgin, IL (Zone 5a) wrote:

I put in 4 purchased primula japonica (pink and burgundy) in 1998. I have clay, highly alkaline soil, and at the time had few trees so the only shade available was on the north side of the house. If you compost them every spring and fall the results are spectacular. I allow some of them to go to seed and then sprinkle the seeds around. Without any further assistance they form little rosettes which are easily tranplanted, and in fact can be hacked in two and transplanted in spring. I now have at least 25, and they grow in excess of 1 1/2 feet tall. I water them perhaps once a week even during 90 degree temperatures in Zone 5A. Highly recommended. And try athyriam felix femina (lady fern) as a companion plant.

Positive

On Feb 24, 2004, ton4lu from Hendersonville, NC (Zone 6b) wrote:

I have been collecting primulas and have found the japanese to be easy to grow. I grow them in moist shade.They only get two hours of sun in the morning and they bloom beautifully.

Neutral

On Aug 30, 2002, Baa wrote:

A perennial Primula from Japan.

Has rosettes of light green, oblong, toothed leaves. Bears 1 or more whorls of salverform, deep reddish purple to white flowers sometimes with an eye.

Flowers April-June

Loves a constantly moist, fertile, neutral to acid soil in light shade, it will tolerate some sun if the soil never dries out.

Very easy plant to grow and looks great in a group.