Cardinal flower is a native wildflower that thrives in wet sites. Its tall spikes of late summer flowers attract hummingbirds and butterflies. Individual plants are not long-lived, but this species will spread by seed and maintain its presence in in your garden. This is a Jenkins Arboretum & Gardens Green Ribbon Native Plant® selection.
Natural Habitat: Wetlands, meadows
Light Requirements: Sun to part shade
Soil Requirements: Moist to wet
USDA Hardiness: Zones 3-9
Size: Height of 2’ to 4’
Wildlife Value: Hummingbirds
Deer Resistance: Not preferred
Cardinal Flower 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. Cardinal Flower seeds 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 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 or fine vermiculite in a baggie and place it in a refrigerator for 60 days. 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. After chilling the seeds for 60 days, sow them by spreading out the contents of the baggie on the surface of your medium.