How to grow Gentiana
Named after Gentius, King of Illyria who first used the plant medicinally (Gentianaceae). Gentian. A large genus of hardy perennials. Most of those in cultivation are dwarf plants suitable for the rock garden, but a few are more at home in the border. Some of them are lime-haters.
Species cultivated G. acaulis (now considered to be a hybrid), gentianella, 4 inches, glossy green tufts of pointed leaves, stemless, deep blue trumpet flowers, spring; vars. alba, white; alpina, compact form; coelistina, pale blue; dinarica, short-stemmed, clear blue flowers. G. angulosa, 2-5 inches, deep lilac, May and June. G. asclepiadea, 2-3 feet, willow gentian, dark blue flowers, July and August; var. alba, white. G. brachyphylla, 2 inches, deep blue flowers, spring. G. cachemirica, 4-6 inches, pale blue, August. G. clusii, 1-4 inches, deep blue, spring. G. dahurica, 6 inches, dark blue, August. G. farreri, 4 inches, Cambridge blue flowers, August and September. G. fetisowii, 6 inches, purplish-blue, August. G. gracilipes, 6 inches, deep blue, summer; var. alba, white. G. freyniana, 4 inches, pale blue, July to September. G. grombezewskii, 9 inches, pale yellow, August. G. hascombensis, 1 foot, blue, summer. G. x hexa-farreri, 3-4 inches, deep blue, August, hybrid. G. hexaphylla, 3 inches, pale blue flowers heavily marked on the outside with darker bars, July and August. G. x Inverleith', prostrate, clear blue, August and September, hybrid. G. lagodechiana, 9 inches, blue, white spotted, August and September. G. lutea, 4-6 feet, pale yellow in tall, unbranched spikes, June to August, bog garden. G. x macaulayi, 4 inches, deep blue, September and October, hybrid. G. pneumonanthe, 6-9 inches, heather gentian, bog gentian or marsh gentian, a native, deep blue, heavily speckled outside with bands of greenish spots, August and September; var. depressa, shorter, more prostrate; 'Styrian Blue' is upright (1i feet) with larger, paler flowers. G. saxosa, 4 inches, ivory-white, summer. G. septemfida, 6-12 inches, bright blue, July. G. sino-ornata, 3 inches, deep blue, September. G. stragulata, 2-3 inches, deep purplish-blue, August. G. verna, 3 inches, deep blue, April and May.
Cultivation It is impossible to generalize about the cultivation of gentians. Some, such as G. cachemerica, hexa-farreri, hexaphylla, 'Inverleith', macaulayi, pneumonanthe, saxosa, sino-ornata and stragulata, will not tolerate lime. Most require a well-drained, gritty soil containing leafmould or peat, but both G. lutea and G. pneumonanthe are bog garden plants. These two, together with G. asclepiadea, will grow in partial shade. Others require sunny positions and although they like ample moisture in summer, they dislike winter wet, hence the need for good drainage. All should be planted firmly. Propagation is by seed sown in March in a cold frame or in pans in a frost-free greenhouse. Seed sometimes takes a year or so to germinate so the compost must be kept moist. G. sinoornata and G. acaulis can be divided in spring, but many other species resent this kind of disturbance.