Plant of the Week: Closed or bottle gentian, Gentiana andrewsii

As the flowering season progresses until the first hard frost, the number of excellent native plants suitable for show in the garden decreases. Oh sure, there are asters, goldenrods, and the native grasses, but few plants that are striking in color.  One of the best late fall plants in flower now is the closed or bottle gentian.  This species grows about 1 to 2' in height and arises from a single taproot, hence it is not prone to spreading because of the lack of an underground runner or rhizome.  It likes calcareous or limestone rich soils and flowers best in full sun to partial shade, with the shade coming at the end of the day.  The key to growing this long-lived perennial is to put it in suitable soil.  Since it is a wetland plant that is associated with prairies, forested wetlands, and fens; it does best in rich, moist soils.  There are some really neat things about this plant in that it has an extremely bitter taste and this means that deer might browse it early, which means you would get multiple flowering stems, but it is generally deer browse resistant.  Another interesting fact is that the primary pollinator is the bumblebee and they are big enough and aggressive enough to open up the end of the flower (or corolla) to pollinate it.  The tiny seeds are usually dispersed by the wind or occasionally water and germination is erratic with high seedling mortality; hence the best route to putting these in the ground is to use plants from a nursery and not seeds.  In addition, since it has one or a few stems arising from the taproot, it will take numerous plants to put on a show in the garden.  Using three probably won't cut it and it will take five or more plants clumped (and probably more) to get a really good show of color.  This would be an excellent choice for a rain garden. Another really positive feature of this plant is that it does not have much of a problem with foliar diseases or chewing insects. This is a more northern species and Kentucky is at the southern edge of its range which goes from Colorado over to the coast and up north into Canada. It is considered rare in Kentucky.  A strikingly similar plant is soapwort gentian, Gentiana saponaria, which also occurs in Kentucky and is infrequent. Most people would be hard pressed to tell the difference unless they actually key out the plants.  Why not try this in the garden to bring out a little blue during this time of the year when we mostly focus on the reds, yellows, and oranges in our trees, shrubs, and bushes.