Zone: 3 to 7
Soil: Sand to loam
Light: Full sun to part shade
Bloom colour: Usually blue to violet
Bloom period: August - October
Height: 2 feet
Moisture: moist to partly dry
Attracts: Bees and maybe a hummingbird
Notes: Closed bottle gentian is a commonly sold perennial that is native to Central and Eastern Canada and as far south as the mid-west and mid-Atlantic states in the USA. It grows about 2 feet high in moist prairie and in sandy areas prone to flooding. Its ability to survive periods of dryness as well as flooding means that it is a versatile plant that is easily grown in the garden.
The flowers are distinctive, with the petals forming a closed corolla with a tiny hole at the apex. This bars most pollinators from entering, but tiny bees can still get through the hole and hummingbirds can insert their beaks all the way to the base of the flower. Bumblebees are important pollinators of bottled gentian because they are strong enough to force the hole open and enter the flower. They will completely disappear inside the flower for a minute or two but you can still see some movement as they bump around in the interior.
Generally, this plant is not fussy about where it is planted and it will grow even in full shade, albeit slowly. The best conditions are full sun, but ensure that watering is regular. This plant will combine well with early blooming goldenrods and will grow in rock gardens or containers.
The deep blue colouration, the flower shape and the interactions with pollinators will provoke curiosity as well as brightening up a fall garden.
There are several other gentians that are native to the region with closed flowers. They include G. linearis shown here which naturally grows on floodplains where the soil is much wetter. It will not tolerate dryness and it requires a greater amount of care. Whether closed or open, gentians are a beautiful and intriguing group of plants that are rarely seen in gardens. |
