Bottle Gentian is a native wildflower with bluish purple blossoms that appear to remain closed. It can grow in the woods or in a sunny bed as long as there is adequate moisture. It blooms in late summer, providing a late season nectar source for bumblebees.
Natural Habitat: Moist woods, flower beds
Light Requirements: Part sun
Soil Requirements: Moist to wet
USDA Hardiness: Zones 4-7
Size: Height of 1’ to 2’
Wildlife Value: Bees
Deer Resistance: Not resistant
Bottle Gentian seeds require 60 days Cold Moist Stratification (abbreviated CMS in many reference guides). Stratification is the process of pre-treating seeds to overcome the seeds’ natural inhibitors that prevent germination in less-than ideal circumstances. They also require light to germinate, so they should be surface sown. This means you do not cover the seed when you sow it.
Cold Moist Stratification can be accomplished by sowing the seeds and setting them outside when temperatures are consistently below 40 degrees. Seeds can always be kept cold longer than the required number of days, so it is fine to sow these in December and leave them outside for the entire winter. They will germinate when the soil warms up in spring.
Alternately, you can mix the seeds with a small amount of moist (not wet) sand, perlite or vermiculite in a baggie and place it in a refrigerator for 60 days. You should see a small amount of condensation on the baggie walls. If you choose to hold them there longer than 60 days, check the seeds periodically. Some seeds will germinate in the baggie. You will see the first root, the radicle, poking out. This is fine if you catch it early. If you let it go too long, the roots will become entangled. After chilling the seeds for 60 days, sow them by spreading out the contents of the baggie on the surface of your medium.