Gentians are hardy plants, renowned for their beautiful flowers in intense shades of blue. The name comes from Gentius, King of Illyria, said to have discovered the beneficial properties of gentians in boosting the immune and digestive systems. Today, as well as being used in herbal medicine, gentian is also used as a flavouring in bitters.
Belonging to the family Gentianaceae and with the botanical name of Gentiana, gentians originate from cooler climates around the world, with many found in mountainous regions. Several hundred species worldwide include annuals, biennials, and perennials. All those generally grown in gardens are perennial, blooming either in spring, summer, or autumn according to the species and bearing flowers that are trumpet, bell or urn shaped.
Several of the most popular species are the tiny spring gentian (Gentiana verna), the mat-forming and spreading autumn-flowering Chinese gentian (Gentiana sino-ornata), and the willow gentian (Gentiana asclepidea), 60-90 cm high. Flowers in shades of blue predominate, plus there are white, pink, and yellow-flowered varieties as well.
How to grow gentians
Gentians are fussy and need cool growing conditions, so it’s important to make sure your garden can really accommodate them. Plant in spring or autumn in rockeries, raised beds, shallow troughs or borders, depending on plant size. Apart from cutting back dead growth once plants are dormant, gentians are best left undisturbed.
Where to grow gentians
Gentians need cool growing conditions, ideally a site in partial shade out of the hottest midday sun, unless growing in cooler and moister regions where the sun is less strong. Soil is important, as some gentians – particularly autumn-flowering varieties – need neutral to acid soil, while others do best on limy (alkaline) soil. Knowing the pH of your soil before buying gentians is therefore important. What’s more, gentians need soil that’s free-draining yet moisture-retentive, with a high level of humus such as leaf mould or finely chipped bark. For containers, add a third by volume of horticultural grit to ensure thorough drainage.
How to plant gentians
Plant gentians in spring or autumn in well-prepared soil (see above). Take care to plant your gentian at the same depth it was growing in its pot so water doesn’t gather around the base of the plant. Firm the soil gently around the roots, water in, and keep watered until established.
How to care for gentians
Gentians need little care once established apart from an occasional thorough watering during dry spells. In pots, water gentians regularly to ensure the compost stays evenly moist. Use collected rainwater as much as possible for lime-hating species because tap water contains lime, especially in hard water areas. Trim back faded flower stems on carpet-forming varieties, leaving the basal rosette of foliage which is evergreen. Cut back taller border gentians in autumn, removing dead growth at ground level.
How to propagate gentians
Although gentians can be propagated by division of larger species, or removal of outer portions of mat-forming types, this should be done with care or avoided altogether as gentians dislike disturbance.
Growing gentian: problem solving
Gentians are prone to stem rots, one of the reasons why growing in well-drained soil is important, as wet conditions can lead to rotting.
Young growth may be susceptible to slug and snail damage. Surround plants with coarse grit as a deterrent, which also aids drainage.