With this flower you bring an alpine character into your rockery or planter. This is how you plant and care for the stemless gentian properly.
Profile of stemless gentian:
Scientific name: Gentiana acaulis
Plant family: gentian family (Gentianaceae)
Other names: trumpet gentian
Sowing time: autumn
Planting time: spring or autumn
Flowering period: May to August
Location: sunny to partially shady
Soil quality: stony to loamy, sensitive to lime, moderately nutritious, humus rich
These information are for temperate climate!
Use in: planters, dry stone walls, natural garden, rock garden, potted garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 3 (-37 °C / -35 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of stemless gentian
Plant order, origin and occurrence of stemless gentian
Gentiana acaulis is translated as stemless gentian, but this rock garden perennial full of character is also known as trumpet gentian. In former times also the name Clusius’ gentian (Gentiana clusii) was used as synonym, today both species are listed separately. They are considered as vicarious species, which are very similar to each other, but occur in geographically separate areas. While Gentiana clusii occurs exclusively on limestone, Gentiana acaulis is calcifugal. Its natural range of distribution is the Alps, the Jura mountain ranges, the Cevennes and the Pyrenees between 800 and 3,000 meters (2,626 and 9,840 ft) altitude. In these areas they grow preferably on acidic silicate soils. Gentians belong to the gentian family (Gentianaceae) and are under protection in some countries.
Characteristics of stemless gentian
As the name already reveals, this species has no distinct stem. Its flowers seem to grow directly from the ground. The leaf rosette of this perennial plant is wintergreen. With a height of 10 centimeters (4 in), it is indeed a tiny plant.
The broadly lanceolate, entire-edged and deep green leaves of stemless gentian are arranged opposite each other in a basal leaf rosette. The leaves are not quite as leathery as those of the closely related Gentiana clusii and are clearly softer.
The stemless gentian blooms between May and August, depending on the location. Even though it is hardly visible, the flowers are individually located at the end of a flower stalk. The bright gentian blue funnel-shaped flowers are formed by five fused petals, the five sepals are also attached like tubes. With exact look one discovers olive-green spots inside the blue flower tube. On the basis of this feature, Gentiana acaulis can be distinguished from the closely related species, Gentiana clusii. In bad weather and at night the calyxes close. They are pollinated by bumblebees and butterflies, but self-pollination is also possible.
From August onwards, the capsule fruits develop, in which the seeds ripen. They are lifted up by the flower stalk, which lengthens towards maturity, and the seeds are spread by the wind when they open.
Stemless gentian – cultivation and care
Gentiana acaulis prefers a sunny to partially shady place, but full sunny locations should be avoided.
As in nature, Gentiana acaulis requires a lime-free, fresh to moderately moist substrate. The substrate should be loose and humus rich. Heavy, compacted soils are unsuitable and should therefore be loosened with sand and gravel.
The best planting time for the stemless gentian is spring or autumn. Heavy soils should be made more permeable by mixing in sand or gravel.
Make sure that the soil is evenly moist, especially in the first period after planting. Fertilization is not necessary, it would even reduce the flowering of Gentiana acaulis.
A division of the stemless gentian in early spring is possible, but not necessary.
Gentiana acaulis can be propagated quite easily by division in early spring. Sowing is also possible, but please note that it is needs cold and dark to germ. It is best to seed in autumn in bowls which are left outside during the winter.
Diseases and pests
Watterlogging can cause stem rot, otherwise leaf spot diseases like gentian rust can occur.
In natural habitats, a blanket of snow usually protects the perennial plant. If there is no snow in the garden and it is freezing cold, Gentiana acaulis should be covered with brushwood as a precaution.
Use in the garden
With its bright blue color, the stemless gentian is an eye-catcher in every natural garden and rock garden. It looks especially naturally if you place the perennial between stones and rocks. Suitable partners are houseleek, bitterroot, cinquefoil as well as Alpine rock-jasmine. The gaps of dry stone walls or alpine arranged trays can also be planted with the perennials.
Well known is the white flowering variety Gentiana acaulis ‘Alba’, while ‘Vierlanden’ has a particularly intense blue color.