Primula obconica
Primula obconica
German primrose
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Taxonomy
Family Primulaceae · Genus Primula
Description
Primula obconica, the German primrose, is a cool-loving, winter-to-spring bloomer that brightens windowsills with vivid clusters of flowers. Keep it cool, bright, and evenly moist for a long, cheerful display.
Common Names
German primrosePoison primrose
Context
nativeRegion
South-central and southern China
usdaZones
9–11 outdoors in frost-free areas; commonly grown indoors as a cool-season pot plant
companionPlants
Cyclamen, Pericallis (cineraria), Viola (pansies/violas), Helleborus, Heuchera, Ferns
culturalUses
Popular winter-flowering gift and windowsill plant; seasonal bedding in mild climates; used for festive displays in late winter/early spring.
Care
Care Requirements
LightBright, indirect light; gentle morning sun is fine. Avoid hot afternoon sun.
WateringKeep evenly moist but not soggy. Water when the top 0.5 in (1 cm) dries; bottom-water if possible. Reduce slightly after flowering.
SoilWell-drained peat/coir-based mix with perlite; rich in organic matter; slightly acidic (pH 5.5–6.5).
FertilizerFeed every 2–4 weeks in active growth with a balanced, low-salt fertilizer at half strength. Flush salts periodically.
HumidityModerate to high (40–60%). Provide airflow and avoid wetting foliage to prevent botrytis.
TemperatureIdeal 50–65°F (10–18°C); nights 45–55°F (7–13°C). Avoid heat above 75°F (24°C) and protect from frost.
Growth & Life Cycle
HabitRosette-forming herbaceous perennial, often treated as a cool-season annual indoors.
Mature Size8–12 in tall and wide (20–30 cm).
Growth RateModerate to fast under cool, bright conditions.
BloomingPrimarily winter to spring; umbels of saucer-shaped blooms in pinks, lilac, white, and red; longest-lasting in cool rooms.
DormancyNo true dormancy; may rest after flowering, especially in summer heat. Can be cut back and kept cool to encourage rebloom.
Propagation
MethodsSeed, Division of offsets, Tissue culture (commercial)
DifficultyModerate—seed needs cool temps and light to germinate; divisions only if multiple crowns form.
Best SeasonSow seed in late summer to early autumn for winter/spring bloom; divide offsets in spring after flowering.
Maintenance & Notes
PruningRegularly deadhead spent blooms and remove yellowing leaves to extend flowering and improve airflow.
RepottingUsually sold as a finished plant; if kept, repot after flowering into fresh mix, keeping the crown at soil level.
Pests & DiseasesAphids, spider mites, thrips, and mealybugs; crown/root rot from overwatering; botrytis in stagnant, humid air. Maintain cleanliness and airflow.
ToxicitySap contains primin, a strong contact allergen that can cause dermatitis—wear gloves. Mild GI irritation possible if ingested by pets or humans. Many modern cultivars are low-primin.
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