Common Names: Kurinso, Japanese Primrose, Candelabra primrose, Valley Red, Japanese Cowslip, Queen of Primroses
Family: Primulaceae
Life form: Perennial forb
History & Introduction
Kurinso derives its name from its native range in Japan, where it is primarily found on the Kuril Islands. Given its attractive inflorescences, Japanese primrose was most likely introduced to the states through the horticulture trade, where it would later be recorded in New York gardens during the 1980’s. Albeit spread sporadically throughout various regions of the United States, it is most concentrated in the Mid-Atlantic, North-Eastern, and North-Western parts of the country.
Identification & Biology
Japanese primrose is deciduous and typically grows between 1-2 feet in height in the spring and summer months. Its vegetative parts are yellow-green. Stems arise from a rosette of basal, spoon-shaped leaves that are unevenly serrated around the margin. These leaves, almost resembling lettuce, have a white midvein and can reach up to 10 inches in length.
Flowering stems produce clustered blooms (also known as inflorescence) in whorls around the stem, with flowers ranging in color from white, pink, purple, and red. The blooming period for Japanese primrose lies between April and June. Individual flowers are tube-like at the base, with the petals initially being fused before dividing into five parts at the tip. Each flower contains five stamens.
Fruits are round capsules, turning brown at maturity. Each capsule contains many individual seeds that are dark brown to black in color. As the capsule matures and dries out, it will split open, allowing for seed dispersal.
In its native range, Japanese primrose thrives in bog environments. In the United States, lacking native competitors or its local geographical barriers, this preference has widened to include any woodland or meadow habitat that is wet and receives some shade. Wetlands, river or lake-beds, and the edge of ditches may therefore be suitable habitat for finding Japanese primrose.
Damage & Concern
Often remarked upon for its habit of escaping gardens, Japanese primrose is a species with significant invasive potential. It can produce dense colonies given the right conditions, readily re-seeding if allowed to reach maturity. There is not yet research to suggest whether or not seeds can be spread by water, however its preference of growing near water bodies suggests this may be a possibility. Additionally, in gardening communities, Japanese primrose is known to propagate by root-cuttings or divisions.
Management & Control
There are a few things you can do to help prevent the spread of Japanese primrose in your area, such as choosing to exclude it from your garden. Likewise, in the event that you happen to be in an area that you know to have Japanese primrose, brush your boots before leaving to prevent the transport of seeds elsewhere.
If you are managing existing populations and performing manual removal, it is important to remove the entire root system to prevent it from coming back next year. Removing flowering heads before they go to seed can also help to limit the spread of this species.
Monitoring & Reporting
As Japanese primrose is a Tier 2 species in LIISMA’s Early Detection and Rapid Response program, we urge you to please report any sightings of the plant to iMap or iNaturalist. Your observations are key to our mission, as they allow us to respond to emerging populations before becoming a larger threat to New York.
iMap is a network for invasive species reporting, allowing concerned parties like LIISMA to discern where invasive species may be popping up, or their geographic extent. Similarly, iNaturalist functions as a biodiversity reporting platform for all kinds of living things—native or non-native—and can help anyone identify and share what species are inhabiting a given area.
If you are interested in playing a bigger part in protecting our local flora and fauna, consider joining LIISMA’s Invasive Species Spotter Program! This program teaches you how to spot emerging invasive species as they arise, giving you valuable detection skills against occurrences of invasive species that were not previously on LIISMA’s radar.
Sources
Bates, C. (2025) Is Japanese primrose invasive? Green Packs. https://greenpacks.org/is-japanese-primrose-invasive/
Glattstein, J. (1982) Immigrants of the plant world came and almost conquered. The New York Times. https://www.nytimes.com/1982/06/27/arts/immigrants-of-the-plant-world-came-and-almost-conquered.html
Iannotti, M. (2024) How to grow and care for primroses. The Spruce.
https://www.thespruce.com/primula-the-primrose-is-no-shy-wallflower-1402858
Kew Royal Botanical Gardens. (2025) Primula japonica. Plants of the World Online.
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:702109-1/general-information
Klingaman, G. (2003) Plant of the week: Candelabra primrose, Japanese primrose. University of Arkansas System Division of Agriculture. https://www.uaex.uada.edu/yard-garden/resource-library/plant-week/primrose-candalabra.aspx
Native Plant Trust. (2025) Primula japonica, Japanese primrose. Go Botany. https://gobotany.nativeplanttrust.org/species/primula/japonica/
NY Natural Heritage Program. (2025) New York State Invasive Species Tiers. New York Natural Heritage Program.
https://www.nynhp.org/invasives/species-tiers-table/
Royal Horticultural Society. (2025) Primula japonica (Pf). The Royal Horticultural Society. https://www.rhs.org.uk/plants/13785/primula-japonica-(pf)/details
