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For Your Garden - September 2020

Native plants provide beauty as well as food and shelter for wildlife. Native species are adapted to the Illinois climate. They require little or no watering and are resistant to drought, insects and most diseases. Because they are perennials, you can welcome their presence year after year.

closed gentian (Gentiana andrewsii)
Photo © John Hilty

Closed gentian is a perennial herb. Its sessile leaves are oval to lance‐shaped with a point at the tip. The simple, entire leaves are arranged opposite each other on the stem. The flowers have deep‐blue to violet petals that remain closed or nearly closed. The petals are connected by a white membrane that sticks out slightly beyond their tips. Flowers are arranged either in a cluster at the stem tip or in the upper leaf axils. The fruit is a capsule that contains seeds. Closed gentian may grow to a height of one to two feet. This species may be found statewide, although it is more commonly seen in the northern one‐half of Illinois than in the southern one‐half. It grows in moist woods and wet prairies. Flowers are produced from August through October.

Classification and taxonomy are based on Mohlenbrock, Robert H. 2014. Vascular flora of Illinois: A field guide. Fourth edition. Southern Illinois University Press, Carbondale. 536 pp.

Illinois Range

Native Plant Information

For more information about Illinois native plants, visit our Native Habitat Descriptions, Requirements, and Plant Lists page. The following publications are available from the IDNR on our publications page.


​Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Gentianales
Family: Gentianaceae

Illinois Status: common, native