Jenkins’ Seed Packets: Foxglove Beardtongue

Foxglove Beardtongue
Penstemon digitalis

Beardtongue is a native, perennial wildflower with purple-striped, white flowers that appear in late spring. After blooming, some gardeners choose to cut back flower stalks to encourage growth of attractive basal leaves. Others enjoy the structural element that the tall seed pods lend to the garden. The seed pods are also a great addition to flower arrangements. 

Natural Habitat: Meadows, open areas
Light Requirements: Full to part sun
Soil Requirements: Dry to average
USDA Hardiness: Zones 3-8
Size: Height of 2’ to 4’
Wildlife Value: Butterflies, bees, hummingbirds
Deer Resistance: Resistant

 Penstemon digitalis seeds require 30 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 are quite small, so cover the seeds lightly when you sow them. A general rule is to cover seeds to a depth equal to their height.

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 30 days. If you choose to hold them there longer than 30 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 30 days, sow them by spreading out the contents of the baggie on the surface of your medium and cover lightly.