How to Propagate Rocky Mountain penstemon?
Propagate by seed in late winter or spring, softwood cuttings in early summer or semi-ripe cuttings in midsummer

Rocky Mountain penstemon · Penstemon strictus
Also known as: stiff beard-tongue
Grow in fertile, well-drained soil in full sun or partial shade. In cold areas, protect plant overwinter with dry winter mulch. See penstemon cultivation
Propagate by seed in late winter or spring, softwood cuttings in early summer or semi-ripe cuttings in midsummer