Rolland Asley

Gentian

Gentiana

While I tried to include most Gentians found in horticulture, additional species of potential in cold climates may be found on this external link.
http://www.efloras.org/florataxon.aspx?flora_id=120&taxon_id=113422

Gentiana acaulis ( Trumpet Gentian )
A short, mat-forming, clumping, evergreen perennial, reaching up to 4 inches x 2 foot ( reports of 6 inches x 3.5 feet ), that is native to the European Alps from Spain to the Carpathians and Balkans.
The elliptic, basal leaves, up to 1 inch in length, form a basal rosette.
The foliage is glossy deep green.
The brilliant, deep blue ( with green spots ), bell-shaped flowers, up to 4 ( rarely over 2 ) inches in length, are borne during late spring into early summer.
Hardy zones 2 to 8 in full sun to partial shade on on moist, deep, acidic, fertile, humus-rich, very well drained soil. It does not enjoy sandy or very light soils.

* excellent photo link found on internet
http://plants.nature4stock.com/?page_id=2664

subsp clusii
Also called Gentian clusii. Similar but smaller, reaching up to 4 x 12 inches, with large, purplish-blue flowers.
Tolerant of limestone soils.

subsp dinarica
Similar except for having broader foliage and abundant flowers that are not spotted.
Tolerant of limestone soils.

Gentiana andrewsii ( Bottle Gentian )
A perennial, reaching a maximum size of 3 x 2 ( rarely over 2 ) feet, that is native to the northeastern United States. It is threatened with extinction in New York State and Maryland.
The lance-shaped leaves, up to 6 inches in length, are luxuriant glossy deep green.
The deep blue flowers, up to 1.6 inches in length, are borne on terminal clusters during late summer to mid autumn lasting a month of more.
Hardy zones 3 to 7 in full sun to partial shade on moist, fertile, acidic to neutral soil. Easy to grow.

Gentiana asclepiadea ( Willow Gentian )
An arching, herbaceous perennial, reaching up to 3.3 x 3.3 ( often under 2 in height ) feet, that is native to Eurasia especially central and southern Europe.
The paired, tapered, lance-shaped to ovate leaves, up to 3.2 inches in length, are glossy bright to mid-green.
The deep blue to purplish-blue, narrow bell-shaped flowers, up to 2 ( rarely over 1.3 ) inches in length, are borne from the leaf axils in clusters of 2 or 3, from mid-summer into autumn.
Hardy zones 5 to 9 in partial to full shade on moist, fertile, humus-rich, well drained soil. It is alkaline soil tolerant.
Propagation is from seed, basal cuttings and division.

Alba
The flowers are white with a bright green throat. It is otherwise identical to the species.

Gentiana clausa ( Closed Gentian )
Also called Bottle Gentian. A perennial, reaching a maximum size of 2 x 2 ( rarely over 1 ) feet, that is native from Quebec south through the Appalatians into Tennessee and North Carolina.
The paired, lance-shaped leaves are luxuriant bright green.
The rich blue flowers are borne during late summer to early autumn.
They are never open completely, hence the name Closed Gentian.
Hardy zones 3 to 7 in partial shade on fertile, consistently moist, very well drained soil. They prefer cool summer climates, especially enjoying cool summer nights.

* photo taken on Aug 25 2013 @ University of Maryland, College Park


Gentiana cruciata
A perennial, reaching a maximum size of 16 inches x 1.5 feet.
The leaves, up to 5 x 2 inches, form basal rosettes.
The deep blue flowers are borne mid summer to early autumn.
Hardy zones 3 to 7 in full sun to partial shade.

Gentiana dahurica
A perennial, reaching a maximum size of 16 inches x 2.5 feet.
The leaves are up to 12 inches in length. The foliage is glossy deep green. The stems are leafy.
The purplish-blue, tubular flowers are borne during late summer.
Hardy zones 3b to 7 in full sun to partial shade. It is easy to grow on acidic soils, however it does not enjoy alkaline soil.

Gentiana dinarica
A vigorous perennial, reaching a maximum size of 6 inches x 2 feet, that is native to Yugoslavia.
The showy, blue flowers are borne during late spring.
Hardy zones 3 to 7 in full sun to partial shade. It loves limestone soils.

Gentiana farrari
A prostrate perennial, reaching a maximum size of 4 inches x 1 foot, that is native to Tibet.
The leaves are very narrow. The intense, mid-blue ( throated white ) flowers, up to 2.4 inches in length, are borne during late summer into autumn.
Hardy zones 5 to 8 in full sun to partial shade on moist, fertile, humus-rich, very well drained soil. It is tolerant of alkaline soils.

Gentiana frigida
A low, upright but spreading perennial, reaching height of 6 inches, that is native to the Carpathian Alps in Europe.
The leaves are up to 3 inches in length.
The yellowish ( with blue stripes ), bell-shaped flowers are borne 1 to 3 at the stem tips during late summer.
Hardy zones 3 to 7 in full sun to partial shade.

Gentiana gracilipes
A rosette-forming, tufted perennial, reaching size of 1 foot x 16 + inches.
The linear leaves, up to 1.2 inches in length, are bright green.
The purplish-blue, bell-shaped flowers are borne atop arching stems, during mid to late summer.
Hardy zones 3 to 7 in full sun to partial shade on moist, acidic, fertile, humus-rich, very well drained soil. It does not enjoy alkaline soils.

Alba
Pure white flowers, otherwise identical.

Gentiana grombezewskii
An erect but spreading, tufted perennial, reaching a maximum height of 1.5 feet.
The leaves are up to 12 inches in length.
The yellow, tubular flowers are borne on terminal clusters during late summer.
Hardy zones 3 to 7 in full sun to partial shade.

Gentiana lutea ( Yellow Gentian )
A strong growing perennial, reaching a maximum size of 6.6 x 2 feet, that is native to mountainous areas in central and southern Europe.
The thick stems bear broad lance-shaped to elliptical leaves, up to 12 x 4.7 inches in size.
The bright yellow, starry flowers are borne on whorls.
Hardy zones 5 to 8 on full sun to partial shade on moist, fertile, humus-rich, well drained soil. It requires cool summers.
Propagation is from seed, basal cuttings and division.

Gentiana makinoi ( Makinois Gentian )
A perennial, reaching up to 2 feet in height, that is native to Japan.
The bright blue to deep purplish-blue, tubular flowers are borne on a leafy stem during late summer into early autumn.
It requires consistently moist, acidic, well drained soil.

Gentiana paradoxa Blue Herold
A perennial, reaching a maximum height of 2 feet. G. paradoxa is native to western Asia from Turkey to the western Caucasus Mountains.
The large, intense mid-blue flowers are borne late summer to early autumn.
Hardy zones 3 to 7 in full sun to partial shade on moist soil. It is easy to grow from seed.

Gentiana saxosa
A prostate perennial, reaching up to 8 inches x 1 foot, that is native to New Zealand.
The spatula-shaped leaves, up to 1.3 inches in length, are deep green.
The purple ( with white veins ), bell-shaped flowers are borne during summer.
Hardy zones 8 to 9

Gentian saponaria ( Soapwort Gentian )
A perennial, reaching up to 28 inches in height, that is native to the eastern U.S. ( from Illinois to Pennsylvania; south to Louisiana to far northern Florida ).
The blue flowers are borne late summer into autumn.
Hardy zones 5 to 9 in light shade.

Gentiana scabra
A rarely seen but spectacular perennial for the landscape border.
The trumpet-shaped flowers are borne early to mid autumn.
Hardy zones 4 to 7, it is easy to grow in full sun on just about any well drained soil though preferring light and peaty. They are not prone to insect pests or disease.

* photos taken on Aug 30 2012 in Columbia, MD

True Blue
Forms a stifly upright ( rare for Gentians ) clump, reaching up to 2.5 x 2 feet in size.
The lance-shaped leaves are luxuriant glossy mid-green.
The intense deep blue flowers, up to 2 inches across, are borne mid summer until autumn frost.

‘Zuikorindo’
Forms a spreading clump, reaching only 6 inches in height, bearing deep pink flowers at the stem tips during early to mid autumn.

Gentiana septemfida ( Crested Gentian )
A dense, tufted, spreading perennial, reaching a maximum size of 20 inches x 2 feet ( rarely over 1 foot in height ), that is native to western and central Asia.
The pointed oval leaves, up to 1.7 inches in length, are mid-green above, bright green beneath.
The abundant, mid-blue to purplish-blue, bell-shaped flowers, up to 2 inches in length, are borne in clusters of up to 8 over a long season from mid-summer to early autumn.
Hardy zones 2 to 9 in full sun ( cool climates ) to partial shade on moist, acidic, fertile, humus-rich, very well drained soil. It is easy to grow, even from seed.

* photos of unknown internet source



Gentiana sino-ornata
A rapid spreading, spreading, carpet-forming perennial, reaching a maximum size of 8 x 18 inches, that is native to Tibet and western China. The stems will root as they spread.
The narrow lance-shaped leaves, up to 1.3 inches in length, form rosettes.
The abundant, intense blue, funnel-shaped flowers, up to 2 inches in length, are borne during autumn.
Hardy zones 6 to 9 in full sun to partial shade on moist, acidic, fertile, humus-rich, very well drained soil. It is easy to grow where the soil is acidic and the summers are cool. It does not enjoy hot humid summers.
Clumps should be divided every 2 to 3 years to propagate and maintain vigor.

Alba
The flowers are pure white, it is otherwise identical to the species.

Angels Wings
The flowers are bright blue with white feathering and striping.
It is otherwise identical to the species.

var lagodechiana
Prostrate in habit, reaching a maximum size of 15 inches x 2 feet. It makes a great plant for the rock garden. The intense mid-blue flowers are borne solitarily late summer to early autumn.
Hardy zones 2 to 7

Gentiana tibetica
A perennial, reaching a maximum height of 3 feet, that is native to the Himalayas.
The leaves are up to 12 x 2 inches in size.
The creamy-white or greenish flowers are borne during late summer.
Hardy zones 5 to 7 in full sun to partial shade. It is more drought tolerant than most Gentians.

Gentiana verna ( Spring Gentian )
A prostrate perennial, reaching up to 4 inches x 1 foot, that is native to the British Isles ( very rare and protected ) and the Alps in Europe where it is much more common.
The oval leaves, up to 1 inch in length, are bright green.
The intense blue, starry flowers, up to 1 inch across, are borne during early spring.
Hardy zones 4 to 9 in full sun to partial shade on on moist, fertile, humus-rich to sandy, very well drained soil. It requires cool summers. Propagate yearly from seed as plants are often short-lived.

Alba
Pure white flowers, otherwise identical.

subsp angulosa
Larger growing, reaching up to 4 inches x 1 foot, with tufts of shiny mid-green leaves, up to 0.8 inches in length. The flowers are borne during late spring. It is otherwise similar.