Penstemon 

(pen' ste-mon)

Common name: Penstemon, Beardtongue

Family: plantain family (Plantaginaceae, formerly listed under figwort family, Scrophulariaceae)

Height x width: 6-36" x 6-18"

Growth rate habit: moderate; upright spikes in clump

Foliage: opposite, lanceolate to ovate-lanceolate, 2-4" long, usually entire, occasionally dentate

Flowers:  2-lipped tubular in terminal racemes, 1-2" long, scarlet to pink to various

Hardiness: zones vary with species

Soil: well-drained, most tolerate drought

Light: sun

Pests and Problems: leaf spots, rusts, root rots from wet soils, aphids, mites (problems seldom serious)

Landscape habit, uses: borders, naturalized, cutting

Other interest: name means 5 (pente) stamens (stemon) refering to its 5 stamens, 4 of which are fertile and the other is often bearded giving rise to the common name; mostly native to western North America and Mexico; popular in England

Other culture:

Propagation: seeds (32,000 seeds per ounce), spring division, mid-summer stem cuttings

Species:

Of the many species available, the following are the more common, cold hardy to at least zone 6.
 
Species height flower color bloom zones other
ambiguus 18-24" pink fading white summer 3-8  
angustifolius 8-12" pink fading blue summer 3-8  
barbatus 36-42" red summer 3-8  
bridgesii 12-36" scarlet summer 4-8 subshrub
cyananthus 12-24" bright blue late summer 4-8  
davidsonii 4" violet purple summer 6-8 creeping
digitalis 48-60" white, purplish summer 3-8  
eatonii 18-24" scarlet late summer 4-8  
eriantherus 4-8" purple summer 3-8  
fruticosus 15-18" lavender, purple early summer 4-8  
gracilis 12-18" pale violet summer 3-8 basal rosette
grandiflorus 30-36" pink, lavender summer 3-8  
hirsutus 15-30" purple, white  late summer 3-8 rhizomatous
humilis 4-12" blue to purple late summer 4-8 rhizomatous
linarioides 12-18" purple summer 4-8  
palmeri 18-48" white, pink tint summer 5-8 scented
procerus 4-12" blue purple summer 3-8 small flowers
rydbergii 12-18" indigo blue summer 4-8  
secundiflorus 12-18" blue, violet summer 3-8  
serrulatus 12-24" blue, purple late summer 5-8 subshrub
smallii 36-42" pink purple summer 6-8  
strictus 24-30" blue, violet summer 3-8  
subulatus 24-30" scarlet early summer 6-8  
utahensis 12-24" red early summer 4-8  
whippleanus 18-24" dull purple summer 4-8  

(species photos courtesy Missouri Botanical Gardens plantfinder)


Cultivars:

Most are hybrids of several species. Those below include the most popular and available in the U.S.
 
Cultivar species flowers other
'Albus' barbatus white  
'Alice Hindley'   pale lavender, white inner 2' tall
'Apple Blossom'   white, pink blush  
'Catherine de la Mare'   bluish fading purple 18" tall
'Charles Rudd'   cherry red, white inner, tubular  
'Chester Scarlet'   scarlet 2' tall
'Coccineus' barbatus scarlet 15-18"
'Elfin Pink'   pink 12" tall
'Evelyn'   pale pink 18" tall, hardy
'Firebird'   deep red  
'Garnet'   wine red, late, long flowers less hardy
'Hewell's Pink'   pink, white spotted inner  
'Hidcote Pink'   light pink, nodding 3-4' tall
'Husker Red' digitalis white maroon leaves
'Mersea Yellow' pinifolius bright yellow 12" tall
'Midnight'   deep purple, bell shape 18" tall
'Papal Purple'   pale purple, tubular 12-15" tall
'Port Wine'   wine red 18" tall
var. praecox f. nana barbatus red, early short
'Prairie Dusk'   purple  
'Prairie Fire'   lilac-red, white mottled inner evergreen in south
'Prairie Splendor'   pink 24" tall
'Rose Elf'   shell pink, many  
'Rubicundus'   scarlet, white inner, wide, tubular  
'Schoenholzeri':'Firebird'      
'Schooley's Yellow'   bright yellow 2' tall
'Sissinghurst Pink'   light pink  
'Sour Grapes'   blue violet, bunched 24" tall
'Stapleford Gem'   blue, bunched 30" tall, vigorous
'White Bedder'   white, tubular 12-15" tall


©Authored by Dr. Leonard Perry, Professor, University of Vermont as part of PSS123 course.

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