The Yellow Gentian, Gentiana lutea, is an imposing 4 foot (1.2 metre) high perennial native to pasture and mountain meadows of Southern Europe and Asia Minor. According to the Roman botanist Pliny, King Gentius of Illyria introduced the root and rhizome of the plant to medicine as a digestive tonic in the 2nd Century BC. It is from this still continuing usage that the plant gained its popular names of Bitter Root or Bitterwort, and from its promoter, the family gained the name Gentiana.

Almost unique among its kind, G lutea will tolerate summer drought, and gardeners who must cope with these conditions should try it. However, it will still require a deep, humus-rich soil. But it is the exquisite sapphire-blue treasures of the high Alps for which the genus is most appreciated. The cultivation of these can be undeniably difficult. Each species has evolved to exploit a specialised niche, and generally will wither quickly if it is subjected to a different cultural environment.

There is no such thing as a 'typical' gentian, but a standard is required against which the others may be compared, and G sino-ornata may best serve this purpose as it and related varieties are among the best known examples of the genus. General comments below are therefore typical of the autumn-flowering G sino-ornata and kind, and specific deviations from the norm are mainly restricted to individual entries in 'Selected Species and Varieties'.

Britain's sole true Gentian is the handsome, blue-flowered marsh gentian, G pneumonanthe, an increasingly rare find in bogs and wet heaths.

Habit

Generally lax stemmed, they range from the ground-hugging, contorted, narrow-leaved mats of the autumn-flowering varieties to broader-leaved, more upright clumps and rosettes usually flowering earlier in the year. The rich blue trumpets of most varieties unfurl from curiously spiralled buds. The somewhat Aspidistra-like G lutea is a glorious exception.

Cultural Requirements

The optimum pairing of sun and a deep, cool, moist root-run throughout the year, is often difficult to provide. Most will succeed in partial shade.

Preferred Soil Conditions

Gentians can be very fussy. Many are calcifuges (lime-haters) and require acidic conditions. Summer-flowering varieties often tolerate some lime if the soil is deep and humus-rich. A few high Alpine rarities demand special mixes of limy grit and organic material, and the care of an enthusiast's Alpine house.

Propagation

Autumn-flowering varieties and G clusii are prone to root congestion, and should be divided and replanted in fresh soil every three years. Other varieties may be propagated by division of offshoots in spring. Propagation of species by seed in autumn often requires a period of refrigeration, and specialist advice should be sought.

Selected Species and Varieties

(Click on external links for photographs.)

• G acaulis - Acaulis meaning 'without a neck', the stemless gentian is less fussy about soil acidity than most, and often provides an Autumn repeat of the Spring showing of green-spotted deep-blue trumpets on short stems.

• G asclepiadea - The willow gentian. One of the easiest gentians to grow, with arching 3-foot (1-metre) lax stems terminating in sprays of deep-blue trumpets. Suitable for a moist perennial border.

• G clusii - The trumpet gentian has low rosettes of oval, glossy leaves that bear azure-blue trumpets in early summer. Less choice than others, but tolerant of alkaline soils.

• G lutea - The yellow gentian. Erect unbranched perennial with whorls of tubular yellow flowers in pale green bracts. Imposing and unusual for those who can manage to get it established.

• G septemfida - The crusted gentian is the first to try for those with a heavy, clay soil, provided drainage is reasonable. Irregular hummocks of foliage become smothered in mid-blue trumpets in late summer.

• G sino-ornata - Classic, evergreen, prostrate and spreading perennial from South-West China that yields the richest of blue trumpets among the fallen leaves of late October and early November. It needs moist soil and acidic conditions.

• G verna - Tubular bright-blue flowers held above small rosettes in spring. Given very gritty, humus-rich soil, this little gem can still be sulky and short-lived.

Garden Virtues

Automatic choices for the Alpine rock garden, troughs, scree gardens etc, for colour late in the year. Elsewhere in the garden, the beauty and intensity of the floral display is worth the effort of cultivation.

Versatility

• Under-plant deciduous ferns with a 'Gentian Lawn' of G sino-ornata. Quietly serene until it turns blue beneath the autumn tints.

• Many high Alpine gentians are extremely tolerant of cold and wind.

Pleasing Associations

In the main Gentians mix most comfortably with stone and gravel.

Botanical Details

Many so-called 'gentians' belong to the closely related genera such as Gentianella.

Family

Gentians give their name to the Gentianaceae, a family defined as consisting of 'sympetalous dicotyledons with corolla twisted in bud and unilocular ovary'. It contains about 80 genera and 900 species, though few are widely known.

Related Genera

• Eustoma - Prairie Gentian
• Exacum
• Gentianella - Felworts
• Menyenthes - Bog Bean, Buckbean