By: Becca Badgett, Co-author of How to Grow an EMERGENCY Garden
Gentian wildflowers are sometimes hard to find in their native habitat, but once you’ve caught a glimpse and seen these plants budding or in bloom, you’ll likely be impressed by their showy beauty. If you’ve not heard of gentian flowers, you may be wondering, exactly what is gentian?
Gentian wildflowers grow all over the world, except on the continent of Antarctica, and have unusual pollination habits. More than 1,000 species have been identified, some in boggy forest areas and others in the desert. Plants in the Gentian species range from a small herb to a tree that grows in the rainforest.
Growing gentian is pollinated by moths, bees, birds, bats and flies. An unusual aspect of gentian flowers is that the buds on some types do not open until the right pollinator forces them to expose their inner pistils and stamens. Many gentian wildflowers have trumpet-shaped blooms.
Growing gentian can be found in a range of colors, depending on their location and species. Blue is the predominant color in the Northern Hemisphere, but blooms of red and white are common in other areas.
Gentians have been used for centuries for their medicinal properties and as cures for a range of ailments. A Croatian king of old, named Gentius, is thought to have first discovered the herbal properties of growing gentian flowers, hence the name. Some gentians are currently used as flavoring for liqueurs and beer; others are used as snakebite remedies and digestive aids.
Those attempting to grow gentians have learned that some of the varieties are difficult to propagate outside of their native habitat, while others adapt well to cultivation. Determine the conditions necessary for the type of gentian wildflower you wish to grow.
Choose an area that is as close to its native growing conditions as possible and plant at the appropriate time. A woodland garden, bog or rock garden may be the right area to experiment with how to plant gentian.
Lisianthus and Persian violet are members of the Gentian family, as are the marsh marigold, Texas bluebell and plants of the Centaury species.
Regular gentian care is necessary for the wildflower to grow and flourish. You’ll find the extra effort is worthwhile when your gentian wildflowers bloom in your landscape.
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Common Name: Gentian
Skill Level: Experienced
Exposure: Partial shade, Shade
Soil type: Well-drained/light
Time to divide plants: March to May
Many gentians are notoriously fickle plants, difficult to cultivate and in some cases reluctant to flower. However Gentiana sino-ornata is not only one of the easiest and most reliable, but also one of the loveliest with spectacular 5cm (2in) bright blue trumpet-shaped flowers. These appear in early and mid-autumn, protruding on very short stalks from the mat of almost mossy textured light green foliage. Lime free soil is essential for this desirable rock garden plant. The Royal Horticultural Society has given it its Award of Garden Merit (AGM).
The beauty of the mountains at home on your patio
As a late bloomer, gentian brings colour to your garden until well into the autumn, and it's also an easy companion: Mr Blue likes to be left alone.
Gentian (officially called Gentiana) is known for its deep blue trumpet-shaped flowers and narrow green leaves. There are also white, pink and yellow gentians, but blue is the most common and is also the best-known: painters have been waxing lyrical about it for centuries. It’s a strong plant that reaches a height of 10-30 cm and thrives in a challenging environment like a rock garden or sandy coarse soil. The more you treat it to fine soil and food, the more the plant will wane. So loving neglect is definitely the way to go.
Propagating wildflowers from seed is similar to propagating cultivated annuals and perennials. Many seeds will germinate as soon as they ripen or dry. Others may require a period of stratification consisting of moist, cool temperatures for six to 12 weeks at around 40 °F. Stratification satisfies the dormancy requirements of the seeds that cause germination to occur naturally during the winter.
Some seeds with hard seed coats need to be scarified prior to germination. This process consists of chemical or physical treatment that breaks down the seed coat to allow the seed to absorb water. Some wildflower species may require both stratification and scarification. Before seeding, learn about the specific germination requirements of the species.
Special care may be required for slow-germinating wildflower seeds, seedlings that are slow to develop, and species with only a few seeds available or rare expensive seeds. Sow these seeds in flats or other containers instead of directly into an outdoor bed. Select a well-drained, well-aerated medium that holds adequate moisture, such as a mixture of peat and sand or commercially available peat-perlite mixes. After seedlings reach several inches in height with a couple of sets of leaves or begin to outgrow the flat, move transplants to individual containers or directly to prepared beds.
It is best to start Prairie Gentian off indoors first.
The seeds should be sown on the surface of a moist soil in a peat pot, about ten weeks before they are due to be planted out in spring.
It takes about one to three weeks to germinate they require a steady temperature of 20 to 22 degrees Centigrade (68 to 72°F) and light to germinate.
Once the Eustoma plants have grown to a height of about 15 cm (6 inches) transplant them into a sunny part of the garden that has good drainage.
Space at about 30 cm (12 inches) apart.
One the the best 'blue' flowers for the gardener are gentians. Yet few people seem to grow them. Yes, some are finicky, but others are quite easy. For rock gardeners, they are indispensible but many lend themselves to woodland gardening as well. Read on to learn more about this ultimate alpine symbol.
(Editor's Note: This article was originally published on April 10, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
Ask a gardener to name a blue flower and gentians often spring to mind. Most gardeners have heard of them even if only a few actually grow them. They are symbols for alpine flora and as most hail from mountainous regions, they are ideal subjects for the rock garden. The ultimate example of their alpine nature is the fact that gentians grow on the slopes of Mt. Everest at an elevation of 18,000 feet! As a genus, they are indeed primarily alpine in nature, occurring in the mountains of western North America, Europe, Andes, Himalayas and Australia/New Zealand. However, with well over 200 species, there are actually some gentians which are better suited for the perennial border or woodland garden. They range from just a few centimeters to giants up to 2 m. The predominant colour is blue, but they do come in white, yellow, purple, red and even green. Strangely, while blue is the dominant colour, those which hail from Australia/ New Zealand are almost all white-flowered! Their trumpet-like flowers are primarily adapted to pollination by bees, which, as a rule, are attracted to blue flowers.
The genus got its name in honour of King Gentius of Illyria who created a remedy against plaque from the leaves and roots of a gentian. Extracts from gentians (in particular G. lutea) are still used in herbal medicines in the modern day. Gentian extract is used to increases the appetite, stimulates digestive juices, decreases intestinal inflammation, treats indigestion, heartburn, liver and spleen disorders, promotes menstruation, strengthens and builds the body, and is helpful for gout and arthritis.
Culturally, some gentians are easy while others are extremely difficult. Some need acidic soil, other alkaline, while others don't seem to care. They all require well-drained, yet evenly moist soil with a reasonable organic content. They detest hot, dry sites. In cool summer areas, full sun is best but in warmer climes, they should be shaded from hot afternoon sun. Oftentimes, the soil pH seems to be the most critical factor to success.
Despite some 200 species, only a handful are common in cultivation. As a rule, they are either spring bloomers or late summer-fall bloomers, but a few will bloom mid-summer to fill the gap. Let's start with the spring bloomers. The spring bloomers are divided into two groups the ‘acaulis' group and the ‘verna' group. The spring trumpet gentians are from the acaulis group and are characterized by low mats of evergreen foliage and large, nearly stemless, solitary flowers in the deepest, richest shades of blue. This group is composed of 7 species G. acaulis, G. alpina, G. angustifolia, G. clusii, G. dinarica, G. ligustica and G. occidentalis. All hail from the mountains of Europe. There are also several hybrids derived from these species. As a rule, all look quite similar but from a gardening perspective, the easiest to grow is G. acaulis (prefers slightly acidic soil), G. angustifolia (a lime-lover see picture above), G. clusii (either acidic or alkaline) and G. dinarica (a lime-lover). They are propagated from seed or by division. The other spring-bloomer, G. verna, forms tufted plants with smaller, more exquisite blue flowers. While charming, it is challenging to keep in cultivation. They require acidic, peaty soil and will wither at the slightest hint of drought.
The mid-summer blooming gentian species all look quite similar, making identification difficult. Even nurseries selling these gentians often get the species names incorrect. There most common species is G. septemfida (G. lagodechiana offered by some nurseries is now classified as G. septemfida). This one has the showiest blooms of the summer bloomers. Plants are herbaceous in nature, forming tufted plants with somewhat sprawling stems to 30 cm terminated by a cluster of bright blue flowers. Some dwarf varieties have solitary blooms. It is perhaps the easiest gentian to grow as they are not particular about soil pH. The most floriferous plants are those grown in full sun and such specimens can be extremely showy. They can be used in the rock garden or the perennial border. Less showy, but equally easy in cultivation is the cross gentian, G. cruciata. The plant habit is similar to G. septemfida but the flowers are a bit smaller, the stems more upright and the plant easy to identify since each flower has 4 petals rather than the standard 5.
Above are Gentiana cruciata and two pics of G. septemfida
Several look-alike species that are often confused are G. bigelovii, G. dahurica, G. decumbens, G. gracilipes and G. waltonii. These also have tufted growth 20-30 cm with upright to slightly arching stems with both terminal and axillary clusters of smallish, more star-shaped blue flowers. Again, these are generally easy in cultivation and while not as showy as some gentians, do provide a welcome spot of mid-summer blue. All of these mid-summer bloomers are best grown from seed.
Shown above are Gentiana dahurica, G. waltonii and G. decumbens
The fall-blooming gentians fall into two main groups the willow gentians and the Chinese gentians. One of the most spectacular and larger gentians is the willow gentian, G. asclepiadea. It blooms in late summer with arching stems up to 1 m in length. The upward-facing flowers are produced in pairs along the upper leaf axils. The flowers all open simultaneously, lending a spectacular blue fountain appearance to the plant. They also come in white or rarely, pink. Moist, peaty, acidic soil in part shade will result in the most lush plants. These have deep roots and resent transplanting so start with young plants and leave them, since like a great wine, they improve with age.
Above are the white and standard blue forms of G. asclepiadea
The Chinese gentians are very late blooming, sometimes blooming trough November! Plants are very frost tolerant. They generally produce solitary, quite large, brilliant blue flowers at the ends of trailing 20-30 cm stems. The outside of the flowers are exquisitely striped in various shades of blue, along with white. There are several species and hybrids included in this group G. sino-ornata, G. ornata, G. farreri, G. hexaphylla, G. ternifolia and G. veitchiorum are the species but the hybrids are often more spectacular than the species. Among the more common hybrids are ‘Kingfisher', ‘Drake's Strain' , 'Juwel', and ‘Delft'. These prefer full sun and demand acidic, moist soil. Unlike most gentians, these are easy to divide.
Above are Gentiana 'Kingfisher', 'Juwel', 'Drake's Strain and G. sino-ornata
Another fall bloomer which should be mentioned is G. paradoxa. This species was only recently discovered in a small region of the Caucasus Mountains. Plants are somewhat like G. septemfida but the relatively large flowers are solitary and the leaves are very narrow and crowded along the stems. They readily hybridize with G. septemfida and often, G. paradoxa offered in the trade are actually these hybrids.
There are a few miscellaneous gentians you may encountered in seed exchanges, specialty nurseries and even local nurseries. The North American native bottle gentian, G. andrewsii and G. clausa, produce upright stems to 50 cm with a terminal cluster of mid-blue, ‘bottle'-shaped flowers. The blooms never open fully. It is certainly not the showiest species, but suitable for a woodland or wildflower garden. Gentiana tibetica produces large rosettes of leathery lance-shaped leaves and stout stems topped by a cluster of greenish-white to greyish-white flowers. This one is grown mostly as a curiosity. Perhaps the most imposing species is yellow gentian, G. lutea. This is the giant of the gentians, with stout stems reaching up to 2m! The leaves are large, leathery and ribbed (somewhat like Veratrum spp.). Plants have a thick taproot and cannot be transplanted once mature. They must be grown from seed. It may take many years for a plant to bloom, but when it does, look out! The yellow flowers are produced in dense axillary clusters and while not as showy as their blue relatives, still make an impressive display just for their size. This species is not fussy about soil as long as it is well-drained and they are situated in full sun. They bloom mid-summer.
Above are Gentiana triflora, G. andewsii and G. lutea
This is just a taste of the gentians that exist. You may come across other species in seed exchanges and specialty nurseries. If you have not tried them, give them a shot. You will certainly enjoy their bright blue flowers and if growing a variety, you can have a splash of blue in the garden from spring through fall.
I would like to thank Bootandall for the use of Gentiana 'Drake's Strain', dpacifici for the Gentiana lutea pictures and kmenzel for the G. andrewsii picture. Your pictures helped complete the article!