With their easy-going nature and jewel-like flowers, many penstemon varieties are a top favourite in my garden. I know that once established they will be drought tolerant, thrive with no extra feeding, won’t need staking and are never nibbled by slugs, snails, rabbits or deer.
The 250 species are mostly from North and Central America and are sometimes called beardtongues, as some have a hairy sterile stamen protruding from each flower. Plant breeders have raised many named cultivars perfect for borders and containers.
Earlier breeding concentrated on large-flowered but rather tender plants prized for labour intensive Victorian bedding schemes. Older plants would be scrapped in autumn and replaced the following year by young stock raised from cuttings the previous summer. Modern breeding has concentrated on hardier, natural-looking cultivars with a long season of flowering. Most are under 3ft (1m) tall, semi-evergreen and perennial with a slightly woody base.
The majority of penstemon varieties flower from midsummer to the autumn and old stems are left in place as protective cover for winter; only when new shoots are growing from the base in spring are they pruned away.
Given a sunny position and well-drained soil, penstemons are long-lived and hold their own well in mixed flower beds and borders. In my garden they occupy a raised bed, growing alongside a prostrate rosemary and shrubby salvias. Further down the garden and in surprisingly heavy soil, a group of ‘Andenken an Friedrich Hahn’ has been flowering reliably every summer for seven years alongside rambling rose ‘Phyllis Bide’ and a young variegated holly.
The shorter species find a home on the rock garden or alpine sink and some, such as ’Schoenholzeri’ have a lax habit suiting prairie plantings with grasses and perennials.
16 penstemon varieties to add to your plot
To help choose which penstemon varieties to grow, there are several excellent series with specific characteristics. The vibrantly colored Rock Candy Series are shorter than usual at 12in (30cm) tall. For containers look to the Patio Bell Series, while the easy-going Elgar Series are particularly long-flowering, and for colder gardens the Riding Hood Series have been bred to withstand chilly winters.
Our selection of 16 penstemon varieties highlights their color range, flower size and usefulness in the garden. Enjoy their bright colors in borders, container gardening ideas and vases.
1. ‘Andenken an Friedrich Hahn’ AGM
- Hardiness: USDA 8b/9a
- Height: 30in (75cm)
- Spread: 30in (75cm)
Named for an 18th century German astrologer, this hardy penstemon bred in 1918 is better known by the old name ‘Garnet’. The small but abundant tubular flowers are, like the gemstone, a rich wine-red.
Blooms open from midsummer to fall and show well against silvery-leaved Artemisia ‘Powis Castle’ and the golden foliage of Ribes cockburnianus.
2. ‘Bredon'
- Hardiness: USDA 8b/9a
- Height: 30in (75cm)
- Spread: 18in (45cm)
One of the Village Series bred at Pershore College in the UK, ‘Bredon’ is a strong, upright cultivar whose large mauve-pink flowers are marked with patterns of dark maroon in the throat. Plants usually overwinter well, flowering from midsummer into autumn.
When thinking about planting partners for your garden border, good choices include the dark leaves of Persicaria microcephala ‘Red Dragon’ or perhaps Eupatorium rugosum.
3. Dakota Burgundy
- Hardiness: USDA 6a-1
- Height: 2ft (60cm)
- Spread: 18in (45cm)
Bred in Oregon, USA, this compact form of P.digitalis is showy and very hardy in well-drained soil. Flowers 1in (2.5cm) long open from mid summer in great profusion, their pale pinkish-violet contrasting handsomely with foliage reddish purple when young but maturing to darker shades.
For a striking combination, plant with airy Gaura lindheimeri ‘The Bride’ and Echinacea purpurea ‘White Swan’.
4. P. davidsonii var.menziesii AGM
- Hardiness: USDA 7b/8a
- Height: 6in (15cm)
- Spread: 20cm (8in)
Known as Menzies penstemon, this subshrub is a great choice for you're currently planning how to build a rock garden, scree or alpine sink. Creeping and mat-forming, semi-evergreen plants with toothed, rounded leaves will hug rocks and produce sprays of violet-blue flowers from late spring into summer.
Mix coarse grit into the soil for improved drainage, and mulching with gravel will help water drain from the necks of plants.
5. P.fruticosus var.scouleri AGM
- Hardiness: USDA 8b/9a
- Height: 16in (40cm)
- Spread: 16in (40cm)
From Western Canada and NW USA , the Scouler penstemon or shrubby beardtongue is a durable evergreen shrub for rock, dry garden or alpine container.
From summer to fall, short racemes of characterful 2in (5cm) long funnel-shaped flowers open in profusion. Both pale and deep purple they are a great plant for pollinators and extend the season after spring-flowering bulbs, pulsatilla and arabis.
You'll find more of the best plants for rockeries in our dedicated guide.
6. P.heterophyllus ‘Catherine de la Mare‘
- Hardiness: USDA 8b/9a
- Height: 2ft (60cm)
- Spread: 2ft (60cm)
I know poor Catherine has had her RHS AGM rescinded for poor performance but when on form, the sheen of pink, purple and blue flowers is remarkable. Typical of a Californian foothill penstemon (P.heterophyllus) these iridescent, nectar-rich blooms open in early summer as accompaniments for peonies, bearded iris and the first flush of roses.
7. ‘Pensham Avonbelle’ AGM
- Hardiness: USDA 8b/9a
- Height: 3ft (1m)
- Spread: 2ft (60cm)
There are over 50 Pensham cultivars in this famous Series bred by Edward Wilson who studied at Pershore College in the 1960s. This one produces blooms of a warm, reddish pink with white throats on tall yet compact plants.
The anise hyssop Agastache ‘Black Adder’ makes a good planting partner, providing soft, aromatic spikes of long-lasting purple.
8. Pensham ‘Czar’
- Hardiness: USDA 8b/9a
- Height: 30in (75cm)
- Spread: 18in (45cm)
Large, white-throated bright purple flowers open over a long period on neat, upright plants. For a lovely planting scheme, set alongside groups of sneezewort with its yellow flowers, or perhaps sunny Helenium ‘Double Trouble’ whose cones of disc florets are surrounded by layers of ruffled petals. Long-flowering H. ‘Autumn Lollipop’ makes bold drumsticks of yellow and brown above collars of small yellow petals.
9. ‘Pensham Just Jayne’ AGM
- Hardiness: USDA 8b/9a
- Height: 3ft (1m)
- Spread: 2ft (60cm)
Cerise purple flowers with darker magenta and white throat markings make an abundant show above neat, pointed leaves.
Tubular blooms will stand out amongst the aromatic grey-green foliage and misty panicles of violet blue Russian sage Perovskia atriplicifolia ‘Little Spire’ a compact type standing at 2ft (60cm) tall. Add white-flowered Agapanthus ’Polar Ice’ for a classic garden color scheme.
10. ‘Pensham Plum Jerkum’
- Hardiness: USDA 8b/9a
- Height: 3ft (1m)
- Spread: 2ft (60cm)
The Bredon and Pershore area in Worcestershire, UK, is famous for its penstemon breeding and of course, also for plums and this purple-flowered cultivar is named after a local plum liqueur.
Strong, upright plants produce dramatic purple blooms with white throat markings. Partner with the flat pink flower heads of Achillea ‘Pretty Belinda’ for contrasting shape and hue.
11. P.pinifolius AGM
- Hardiness: USDA 8b/9a
- Height: 8in (20cm)
- Spread: 10in (25cm)
Perfect for the rock, dry garden or a sunny raised garden bed, the pine-leaved penstemon from Southern USA and Mexico is a low, shrubby plant whose pale, evergreen needle-like leaves make a fine backdrop for narrow scarlet-orange flowers 1in (2.5cm) long.
Although good garden drainage is important, this penstemon tolerates clay soil well. Mulch with grit or fine shingle.
12. ‘Raven’ AGM
- Hardiness: USDA 9b/10a
- Height: 3ft (1m)
- Spread: 18in (45cm)
The blooms of this most dramatic of penstemons are a purple so deep that buds almost appear to be frosted with a slaty bloom. Opening reveals white throat markings flanked by a reddish glow.
From the famous Bird Series, this is not the hardiest of penstemons, so use as bedding plants and always strike a few summer cuttings to overwinter.
If you love the look of this dark flower, our guide to the best black plants has plenty of other suggestions you could add to your planting scheme.
13. ‘Schoenholzeri’ AGM
- Hardiness: USDA 8b/9a
- Height: 3ft (1m)
- Spread: 24in (60cm)
Better known as ‘Firebird’, this well-loved penstemon has been around since 1939 and makes a fine border plant whose 3in (8cm) long carmine flowers with magenta throats are perched above narrow leaves.
Flowers are borne over a long period and plants cope well with wetter soil types. A good one for late summer, perhaps alongside mauve-blue Agapanthus ‘Radiant Star’.
14. ‘Stapleford Gem’ AGM
- Hardiness: USDA 8b/9a
- Height: 30in (75cm)
- Spread: 18in (45cm)
My favourite penstemon varieties are those where pinks, blues and lilacs wash and merge. This one dating back to the 1930s bears tubes moody mauve on the outside but lit by paler tips and throats marked with pale lilac and darker stripes.
Use this vigorous penstemon as an accompaniment to the fragrant, repeat flowering pink shrub rose ‘Gertrude Jekyll’.
15. 'Strawberries and Cream’
- Hardiness: USDA 8b/9a
- Height: 2ft (60cm)
- Spread: 18in (45cm)
We don’t always need subtle and from the large-flowered Ice Cream Series, this penstemon is a confection of pale and rich pink, with strong throat markings and a long flowering period.
Go mad and set with pink and white Penstemon ‘Melting Candy and darker P.‘Blackberry’, or place with dark-leaved, white-flowered Dahlia ‘Twyning’s After Eight’.
16. ‘White Bedder’
- Hardiness: USDA 9b/10a
- Height: 30in (75cm)
- Spread: 18in (45cm)
If you're searching for white flowers for a white-themed border or to complement bright colors, white-flowered cultivars are always useful.
This is a large-flowered penstemon dating from 1912 and has been known as ‘Snowstorm’. Buds are tinged pink but open to white and would make a creamy-pink mass with rosa ‘Pink Gruss an Aachen’. Plants need a well-drained soil and full sun to establish well.
What's the best penstemon variety to grow from seed?
If you're growing flowers from seed, penstemon plants usually bloom in the same year from seed sown thinly and evenly into a pot or tray in spring.
Place seeds in gentle warmth around 60-65˚F (15-18˚C) and they should germinate within three weeks. Transplant seedlings singly to 3.5in (9cm) pots and grow on ready for planting out.
P. ’Sensation Mixed’ delivers a wide range of colors at 2ft (24in) high or for smaller flowers in pink, purple and rose, choose P ‘Miniature Bells’. From unusual P.digitalis ‘Mystica’ expect bronze leaves followed by stems of lavender pink flowers.
Can all penstemon varieties be propagated by cuttings?
Penstemons root readily from slightly riper stems taken in mid to late summer. The plants resent disturbance, so to expand or start a new group, raising new plants from cuttings is the best method. Rooted cuttings are also good insurance against winter losses in colder regions.
Take non-flowering side shoots (or remove flower buds), trim to 3-4in (8-10cm) by cutting under a leaf node, remove lower leaves and cut any larger ones by half. Insert five into a 3.5in (9cm) pot of 50:50 multipurpose compost and grit, water in and cover with a lid, or ventilated polythene and place out of full sun to root.
There are more tips on how to take cuttings from plants in our dedicated guide.
