Minnesota’s Native Gentians

Bottle gentian
(Gentiana andrewsii)

Bottle gentian grows one to two feet tall in wetter places, but the stems may sprawl on the ground so that the plant looks shorter than it is.  Bottle gentian blooms August through September, its petals fringed at the tip with white and so tightly overlapped that bumble bee pollinators must fight their way inside. The flowers bloom in clusters like deep blue bouquets on the tops of the plants and sometimes in the leaf axils (where leaves meet stem).  Leaves grow in pairs, each pair at right angles to the ones above and below it, which helps us identify most gentian plants even when they aren’t in bloom.

Stiff gentian 
(Gentianella quinquefolia)

Stiff gentian makes us think of bottle rockets, with its unmistakable pointed, purplish-blue, tube-shaped flowers, often in clusters of five. As with bottle gentian, pollinators such as bumblebees must fight their way into stiff gentian’s almost-closed blossoms. Leaves grow in pairs, each pair at right angles to the ones above and below, and often clasp the stem.  Found mainly in southeastern Minnesota, stiff gentian grows from 9 to 30 inches tall in wetter places (and, surprisingly to us, sometimes drier places, too) and blooms from August to October.

Downy gentian 
(Gentiana puberulenta)
While most gentians prefer wetter places, you might find downy gentian in drier parts of the prairie and on hillsides.  Downy gentian can grow up to 18 inches tall (although its stems often sprawl, making it look shorter), and blooms from August to October with five-petaled flowers at the top of the stem like a cluster of upturned bells.  Part of its scientific name, puberulenta, means covered with fine, soft, white hairs, and both the stem and bases of the narrow leaves, which grow in pairs, are softly downy. If you want to see downy gentian open and blooming, be there when the sun shines–flowers close at sunset, something we sadly discovered when we waited too late in the day to photograph one.  While downy gentian might be mistaken for pleated gentian because both have connected petals, when you look down into a downy gentian you’ll see white stripes down into the throat.  Pleated gentian has white dots inside and is much less common (we know, we looked hard to find it). 

Greater fringed gentian (Gentianopsis crinita)
Greater fringed gentian grows 12 to 30 inches tall in wetter places, and its flowers, one to a stalk, have four deep blue fringed petals. The flowers, which bloom in August and September, open with the sun and twist closed at sunset. We misidentified greater fringed gentian as lesser fringed gentian when we first saw it, since the differences between the two are subtle.  Greater fringed gentian can grow taller and has longer fringes, but even now we are not always sure which one we’re seeing.  Greater or lesser, we’re always grateful for blue among late summer grasses.  

Lesser fringed gentian (Gentianopsis virgata)
When we first saw a greater fringed gentian, it seemed so diminutive that we were sure it was the lesser fringed gentian. It wasn’t, but lesser fringed gentian is equally as beautiful and fun to find, blooming in August and September in wetter places and ditches. While a single plant may produce several deep blue four-petaled blossoms, usually only one blooms at a time. Lesser fringed gentian grows 3 to 18 inches tall, although its spindly stem might sprawl, making the plant look shorter than it is.  How to tell lesser fringed gentian from greater fringed gentian?  The plant itself, the leaves, and the fringe on the petals are all said to be smaller than greater fringed gentian, but since we’ve never seen them side by side to compare, we still scratch our heads a little when we encounter any fringed gentian.  

Great Lakes gentian
(Gentiana rubricaulis)
A flower of northeast to north central Minnesota, Great Lakes gentian might be mistaken for the more common bottle gentian—we puzzled over it when we first saw it alongside a boardwalk at Sax Zim Bog.  Great Lakes gentian’s color is a little lighter than bottle gentian, sometimes edging into pink, and its unfringed petals are a little less tightly closed What made us sure it was Great Lakes gentian were the bumblebees easily flying in and out of the almost closed flowers instead of having to wrestle their way in like they do with bottle gentian. Smooth glossy leaves grow opposite on a smooth stem, which is often red-colored (part of the scientific name, rubricaulis, literally means red stemmed or stalked). Great Lakes gentian grows 1 to 2 feet tall and blooms August through September in moist places that have at least some sun. True to its name, it mostly grows in states or provinces that border the great lakes.

Pleated gentian
(Gentiana affinis )
Pleated gentian is a flower of special concern in Minnesota, where it grows in the northwestern part of the state at the eastern edge of its range.  Of the true blue gentians, this is the last one we tracked down, finding it, after much searching, nestled in a saline prairie. (Saline prairie itself is rare in Minnesota, with its patches of saltier, white-coated ground and foxtail barley grass bending in the breeze.) Pleated gentian has opposite leaves, each pair at right angles to pairs above and below it, and grows six to sixteen inches tall, blooming in August and September. The five-petaled flowers look similar to downy gentian with pleats of tissue between the petals, but the inside of a pleated gentian flower is dotted with white to greenish spots–unmistakable once we saw it. We’ve only ever found pleated gentian once, but when we did, jubilation ensued.

Yellow gentian
(Gentiana flavida )
Yellow gentian is a flower of southeastern Minnesota and except for the color looks very much like bottle gentian, its petals almost closed in a tube. Its lovely cream-to-pale-yellow flowers bloom in a cluster at the top of the plant like a little bouquet between August and October.  Like many gentians, cream gentian’s leaves grow in pairs at right angles to each pair above and below.  We’ve seen a whole hillside of cream gentian blooming along a roadside in southern Minnesota, and we’ve also seen them scattered in a prairie at Great River Bluffs State Park, a delicate delight

American spurred gentian (Halenia deflexa )
Even though its scientific name is different from other members of the gentian family, American spurred gentian actually does belong to the same family as most gentians. It’s also known as green gentian, since everything about it is green, blending into the forests where it grows. Clusters of small, light green, distinctively shaped flowers on long stalks in a whorl at the top of a single stem look like space capsules blasting off. A spur at the base of each flower gives the plant its name.  Pairs of opposite leaves are widely spaced on square stems, and the fruits, when they form, look like little horns protruding from the flowers. American spurred gentian grows up to 30 inches tall in Minnesota’s northern forests and blooms in July and August. 

Horse Gentian’s

Why are horse gentians called gentians when they actually belong to the honeysuckle family?  We don’t know, maybe because they are bigger (like horses?) growing up to four feet tall. We do know that outside of the gentian name we don’t see much resemblance to gentians (but then, we’re not botanists). We’ve seen early horse gentian in the fall, identifying it by its bright orange-red fruits, and we’ve yet to see late horse gentian at all. Both bloom in May and June, so we’ll look for them in this spring (2023). When we do see them blooming we’ll be sure to let readers know. Here’s what we’ll look for:

Early horse gentian (Triosteum aurantiacum)

We haven’t seen either horse gentian in bloom, but we thought perhaps early and late referred to their bloom times.  Nope. Minnesota Wildflowers website lists both as blooming in May and June, growing 2 to 4 feet tall.  Both grow in hardwood forests, although we’ve seen early horse gentian in a prairie as well.   Early horse gentian’s velvety, purplish-red, five-petaled flowers may shade toward pink and open up more than late horse gentian.  Leaves are large, hairy (especially underneath), opposite, and stalkless on an unbranched stem.  Like many gentians, each pair of leaves grows at right angles to the pairs above and below.  Early horse gentian fruit look like little red-orange eggs with the five flower stamens sticking up from the top like a spiky crown or a wild hair day.

Late Horse Gentian (Triosteum perfoliatum)

Like early horse gentians, late horse gentian grows 2 to 4 feet tall in the shade of dry woods and on dry prairies and blooms in May and June with reddish brown, velvety-looking, tube-like flowers that ripen into yellow fruits.  Late horse gentian’s large leaves are opposite, wavy at the edges, and hairy, especially underneath, each pair at right angles to the one above.  Unlike early horse gentian, these leaves join at the base and look like a single leaf punctured by the stem.  How to tell early horse gentian from late horse gentian in bloom? We’ve read that besides the leaf edges and shape one difference is the soft hairs that cover petals and stems, which are only half a millimeter long on late horse gentian and a whole millimeter long on early horse gentian.  In case we forget our millimeter ruler, we’ll look at the leaf shape to help us tell the difference when we find them.

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