Penstemon plants ( Penstemon ) are herbaceous perennials belonging to the snapdragon family ( Scrophulariaceae ) . The plant ’s name staunch from two Greek words meaning " five " and " thread , " referring to the fact that penstemon plants have five stamens . Penstemon typically prosper in dry , well - drained territory in fully cheery locations . accord to Southwest Colorado Wildflowers , more than 250 Penstemon coinage produce in North America .
Penstemon Barbatus
Penstemon barbatus , also promise southwestern penstemon , works well in rock garden and borderline . aboriginal to New Mexico , Arizona and Utah , this penstemon variety show is winter hardy in U.S. Department of Agriculture zones 4 to 8 . Penstemon barbatus typically grows between 2 and 3 foot in elevation with a 1- to 1 1/2 - foot spread . Tubular , red prime bloom in May and June . The narrow-minded , pointed leave attain up to 6 inches farsighted and look similar to willow tree leaves . This penstemon works once in a while stand from leaf spot disease .
Penstemon Caespitosus
The penstemon caespitosus plant , also called the beard glossa , is native to Colorado , Wyoming and Utah . This Master of Arts in Teaching - forming penstemon species only pass about 3 inches in height and 9 inches in width . fragile empurpled bloom bloom profusely from May through July . Hardy in USDA zones 4 to 7 , penstemon caespitosus is often used in native industrial plant gardens and rock-and-roll gardens .
Penstemon Canescens
Penstemon canescens , often shout out gray beard knife , is native to the Appalachian Mountain part of the eastern United States . This clump - forming penstemon change reaches between 1 and 3 feet in height with a somewhat smaller spread . Violet flowers bloom in May and June . This penstemon plant boast strong , gray stems and haired , dark-green leave . Leaf spot and root rot are sometimes problems . Winter hardy in USDA zones 5 to 8 , penstemon canescens works are commonly used in native industrial plant gardens and border .
Penstemon Cobaea
The penstemon cobaea plant life variety , also prognosticate the dew heyday , is a clump - forming industrial plant that reaches up to 2 feet in pinnacle and 1 1/2 foot in width . Winter hardy in USDA zone 5 to 8 , this penstemon mintage by nature fly high in North American prairies and jolting bluffs . The pink , purple or white heyday bloom in May and reach up to 2 in long . This penstemon plant feature stiff , downy stems and pointed , downy folio . Penstemon cobaea exercise well in wild gardens , aboriginal plant garden and careen garden .
Penstemon Digitalis
Penstemon digitalis , more commonly called beard tongue , is indigenous to the field , woods and prairie of the southeastern and easterly United States . These plants display tube-shaped , white flowers from April through June . Reaching between 3 and 5 feet in height and 2 foot in width , this penstemon variety is hardy in USDA zone 3 to 8 . The penstemon digitalis plant grows well when mass planted in borders , native plant gardens and naturalized country .
Penstemon Heterophyllus
Penstemon heterophyllus , also known as foothill penstemon , course grow in California ’s grasslands and woods . This penstemon flora thrives in USDA hardiness zones 6 to 10 . Blue blossom bloom from May through July on stems get through up to 1 1/2 feet in height . The penstemon heterphyllus works well when planted in teetotal soil on hillsides or in rock and roll gardens .
