American Penstemon Society
Collects and shares details on species identification, propagation, successful growing methods, and native locations. Includes images and library.
Personal website of Bob Davies aimed at fostering interest and appreciation of penstemons in the United Kingdom.
Looks at three of the penstemon varieties - P. cardwellii, P. deustus, and P. venustus. By Andrea D. Wolfe.
Explores the penstemon seed germination methodology. Details on the prescribed germination environment for each variety.
Plant Encyclopedia: Penstemon
Information from Better Homes & Gardens includes requirements, appearance, uses, special features, top varieties, compatible plants, and propagation.