Gentiana x intermedia ‘True Blue’ / Bottle Gentian 3 stars/ Good
Gentiana ‘True Blue’ is a 2008 introduction from breeder Darrell Probst who, in his quest for a longer flowering gentian, crossed a Gentiana makinoi hybrid with a Gentiana scabra hybrid.
Flower description/bloom time
Purple-blue to true-blue, upward facing vase-shaped, 1.5-inch long flowers. Blossoms appeared in evaluators’ gardens anywhere from mid-July to Mid-October. At peak bloom, flowers covered the entire plant.
Dark green, medium textured ovate leaves.
Habit and growth rate observations
Plants produced a strong bushy, tight-clumping habit that ranged from 10 inches tall and 8 inches wide to 17 inches tall and 23 inches wide.
Site preference—soil and light
Clay loam, well-drained soil. Prefers full sun to part shade. Protect from the afternoon sun. Plants do not like water-logged soil.
Successes and possible drawbacks
‘True Blue’ bottle gentian attracts butterflies and hummingbirds, is deer resistant and can be used as a cut flower. Evaluators noted that while plants began as healthy specimens, the foliage turned yellow with a bronze or purple cast in mid-July. Some plants died by the third year of the evaluation. Plants may need supplemental water during drought. Cut the foliage back in spring or fall to produce new growth. Spent flowers turned brown.
Notes from growers/retailers
‘True Blue’ bottle gentian can be used as a border plant in perennial and cottage gardens. Pair gentians with other moisture-loving plants such as Carex and Iris for beautiful color and texture combinations. (However, do not place them in areas where they will be water logged.) Gentians can also be used in rock gardens, alpine beds, containers or perennial borders.
Parting “shot”—the overall evaluation results were Good. ***
Although some plants disappeared by the second year of the evaluation and foliage was marred by mid-season, evaluators felt the flowers rated a “4” because of their true-blue color and continuous bloom.