The soapwort gentian grows to about 1 ½ to 2 feet in height. I have heard 3 feet in a garden, but not in mine. Stems begin the season upright, but as they get longer, the stems arch over to lie on the ground. As the buds form stems arch back up to keep the blooms off of the forest floor, forming an 'S'. The 'S's radiate out to from a central root stock. Up to 8 flowers are carried in clusters at or near the end of each stem.
 Gentiana saponaria |
Blooms are more toward the purple side of blue in color. As the blooms age, the veins darken to a violet-purple, giving the clusters a two-toned effect in color. Blooms are about 1 ½ inch in length. Each bloom is shaped like an old fashioned GE Christmas tree bulb in my mind's eye. Some call the blooms club-shaped. The blooms do not open so there is always an air of expectancy about the plants. Perhaps the appearance is of always a bud, but never a bloom.
Blooms have an amazing internal structure. The 'closed' end of the flower is not sealed, but overlapped. There are pleats, or folds, toward the top of the flower as in an accordion. Darwinism definitely at work here, for only the most fit need attempt to enter. It takes a rather large and strong bee to force the folds apart and make an entrance for the nectar at the bottom of the bloom. After feeding, the bee must then force its way back out. Occasionally they will spend overnight in the blooms. I have picked up trays of plants in bloom in the nursery in early morning hearing the flowers give a buzz-buzz as bloom stems sway to my steps.
Generally, the plants are found along the outside edge of a wood, or if inside, located in openings. They can also be found in woody thickets. Usually the areas will be in or near seepage areas, or lowlands that flood on occasion. Success in the garden with soapwort gentian is dependant upon mimicking Mother Nature. Give your plants high open shade, preferably an eastern exposure. Too little light and bloom production is reduced. Too much sun causes the foliage to yellow and the blooms to wash out in color. Extra moisture is not an absolute if transplanted into a decent soil containing compost, mulching with chopped leaves or hardwood fines to retain moisture levels. Know your soil pH, for the soapwort gentian wants to be free of lime.
Most gardening literature ignores the range of this native plant when assigning a hardiness rating of 6 to 9. I know for certain it is hardy to zone 5 and probably well into zone 4.
In my garden I see the soapwort gentian come into the bloom the latter part of August and will still be flowers in mid-December. It is not unusual to see the blooms with snow on them. Imagine if you will, those intense blue gentian blooms with the fall colors of foliage drifting down to frame the plants in shades of red, yellow, and russet. Add companions of the great blue lobelia, or cardinal flower (L. cardinalis, siphilitica), turtlehead (Chelone), ferns, and grass of parnassus (P. glauca).