How to Grow Penstemon Strictus From Seed

Penstemon strictus, also called stiff beard tongue, are colorful perennials that develop bell-shaped blue flowers in summer. The inside of the blooms are lined with hairs, which is the characteristic that inspired their common name. Start the plants from seed by sowing them in a container during late fall and placing the container in a protected outdoor location for two to three months. This process, known as cold stratification, greatly increases the chances of germination.

Things You'll Need

• 4-inch plastic growing container
• Builder's sand
• Peat-based growing mix

Instructions

1. Fill a 4-inch plastic growing container with a combination of half builder's sand and half peat-based growing mix. Water until the mixture feels moist.

2. Press the Penstemon strictus seeds very lightly into the surface of the mixture.

3. Sprinkle a 1/4-inch layer of builder's sand on top of the growing mixture.

4. Place the container outdoors in a location that is protected from exposure to direct sunlight.

5. Examine the container regularly and add moisture any time the surface of the mixture is dry.

6. Move the container to a location that receives several hours of indirect sunlight each day when you notice the seeds beginning to sprout in spring. Continue to water any time the surface of the growing mixture feels dry.

7. Transplant the seedlings to their permanent location after they have developed two to four sets of leaves.

Tips & Warnings

• Penstemon strictus is hardy in U.S. Department of Agriculture zones 3 through 8.

• Penstemon strictus does best when planted in full to partial sun and well-drained soil.

References

• Michigan State University Extension: Penstemon Strictus--Stiff Beard-tongue
• Horticulture: How Do I Cold Stratify Perennial Seeds?
• Mountain States Wholesale Nursery: Penstemon Strictus
• Lady Bird Johnson Wildflower Center: Penstemon Strictus