One is by spores, a sexual means of reproduction good for mass production. The second is asexually, by taking cuttings. Cuttings are great for species like the rabbit's foot fern that put out runners.
Penstemons are short-lived perennials that can suffer in winter. To avoid losses, pruning penstemon is best done in spring. It's also a good idea to take summer cuttings to prevent winter losses.
Allow the wound to dry out for a few days, then transfer the new plant into a new pot and water well. Keep in a warm spot. You can also propagate yuccas from 20cm stem cuttings in spring, in a similar ...