How to grow penstemon?

How to grow penstemons

Penstemons are valuable garden plants for their long-flowering qualities. They’re also popular with bees.

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Penstemons vary, with some being suited to the alpine garden while the majority are at home in the heart of a herbaceous border. Border penstemons are praised for their tubular late summer flowers in an array of dramatic colour. The flowers look very similar to those of a foxglove.

While often described as hardy perennials, in a wet and cold winter plants can be lost. To offer them protection plants are not cut back until spring.

Discover how to grow penstemons in our comprehensive guide, below.

Take cuttings of your favourite penstemons every few years to ensure you have the next generation in place.

Where to plant penstemons

Penstemon ‘MacPenny’s Pink’

Border penstemons are perfect for the middle of a mixed border. They enjoy a fertile, reasonably moist soil that is free-draining. Full sun or light shade is ideal.

How to plant penstemons

Purple-blue penstemon ‘Catherine-De-La-Mare’

Plant in spring so that new plants get a foothold before having to face the winter. Stems are strong so it’s only in very exposed garden that plant supports will be required.

How to propagate penstemons

Taking penstemon cuttings

Penstemon cuttings can be taken in late summer or early autumn. Select soft growth without a flower. Cut each cutting back to below a leaf joint and remove the lower leaves. More than one cutting can be put into a pot of cutting compost as long as the leaves don’t touch.

Place them in a sheltered spot in the garden or a cold frame. All being well they’ll be ready to plant out the following May.

Penstemons: problem solving

Topping a pot of newly-planted penstemon cuttings with gravel

Penstemons are fairly short-lived plants. Take cuttings of your favourite penstemons every few years to ensure you have the next generation in place.

To prevent plants from failing to make it through winter, don’t cut faded stems back hard until spring.

If you continue to fail with penstemons ensure that the soil is not waterlogged. Dig in horticultural grit to improve drainage.

How to care for penstemons

White and purple-pink flowers of penstemon Laura’

In spring apply a general purpose fertiliser to your mixed borders. Water freshly planted penstemons for the first summer to help them establish on a dry soil.

In autumn cut back the faded foliage by just a third to prevent windrock and then cut the remaining foliage back hard in spring after the last frost.

Penstemons for quick colour

If you’re looking at your border in late summer and need to add some instant colour, penstemons are the answer. Plant in groups of three or five for impact. Most border types will continue to flower up until the first frosts.

Deep-purple flowers of penstemon ‘ Sour Grapes’

Great penstemon varieties to grow

  • Penstemon ‘Andenken an Friedrich Hahn’ (formerly known as ‘Garnet’ ) – wonderful crimson flowers from June to September with narrow dark green leaves. Height 75cm

  • Penstemon ‘Raven’ – dark maroon flowers from June to October. Reaches a height of 100cm
  • Penstemon ‘Sour Grapes’ (pictured) – stunning, almost aluminous pale purple flowers from June to October. Reaches a height of 60cm
  • Penstemon ‘Osprey’ – pink and white flowers from June to October. Height of 90cm
  • Penstemon linarioides subsp. sileri – bright yellow flowers on a lower growing plant of only 45cm. A half-hardy type for the front of a border with flowers in July and August. Not widely available

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Find many more great varieties of penstemon to grow here

Penstemon

Traits

  • Sun
  • Birds

Flowering Season

Summer

Genus

Found mainly in the Americas from Alaska to Guatemala, the 250 species of perennials and subshrubs in this genus range from tiny carpeting plants to rapid growers that can exceed 4 ft (1.2 m) tall. In recent years many new garden varieties have become available, generally with increased hardiness and increased flower production. In favourable conditions, these are reliable plants, suitable for border planting, rock gardens, woodland gardens, and “wild” gardens. The pretty flowers resemble those of the foxgloves (Digitalis), and, indeed, they belong to the same family the family Scrophulariaceae. Native Americans used several species, primarily for their analgesic and styptic properties but also to control stomach disorders.

Appearance

Some Penstemon species are mat-forming, others are shrubby, but most form clumps of simple linear to lance-shaped leaves that grow in opposite pairs on the stem. The foxglove-like flowers appear mainly in summer, borne at the end of erect flower spikes; they are slightly hanging and tubular to bell-shaped, with 2 upper lobes and 3 larger lower lobes. They come in blues, reds, white, and bicolours. Many cultivars have been bred, selected for their generous numbers of flowers.

Cultivation

Of variable hardiness, penstemons are best grown in a position in full sun or half-sun with moist well-drained soil. Alpine species and those from southwestern USA often prefer gritty soil. Cut plants back hard after flowering has finished. Certain species may need protection over winter with a layer of mulch. Gardeners in cold areas should try the new hardy types. Propagate by division or from cuttings of non-flowering stems. The species may be raised from seed.

Gardening Australia suggests you check with your local authorities regarding the weed potential of any plants for your particular area.

© Global Book Publishing (Australia) Pty Ltd from Flora’s Gardening Cards

List of Tubular Flowering Plants

Tubular flowers are known to botanists as one of a group called sympetalous. This means that the petals are joined, either wholly, or partly. Hummingbirds are particularly attracted to tubular-shaped flowers, especially if the flowers are red. Scientists at Bellarmine University suggest that in the Jurassic period, the long, tubular mouth-parts of pollinating insects and birds evolved in response to feeding on tubular flowers. If you are planning on planting tubular flowering plants in your yard, get ready for a beautiful flower show and lots of birds and insects as well.

Turk’s Cap

Popular in Texas gardens, the turk’s cap is a herbacious mostly perennial shrub that will grow to a height of 4 feet. In warmer climates, it will bloom year-round with deep, red or white flowers that are twisted, like a turk’s cap, and tubular. Turk’s cap is drought-tolerant and grows well in the shade. A heat-loving plant, it is hardy in USDA Zone 7.

Scarlet Salvia

Another red-flowered hummingbird favorite is the scarlet salvia, also called red salvia. Native to Brazil, this plant is frost-sensitive but otherwise easy to care for. The striking, red tubular flowers bloom in clusters on tall spikes in the summer, and will last until the first frost. Scarlet salvia does like a moist soil so regular watering is important.

Cape Honeysuckle

Cape honeysuckle can be planted in partial shade, although it prefers full sun. This is a very fast-growing shrub and is considered invasive in some areas. Cape honeysuckle is a low-maintenance plant that requires very little water once it is established and, in mild weather areas, will bloom all year. The flowers are tubular and bright orange. The cape honeysuckle is hardy to USDA zones 9a to 11.

Penstemon, Penstemon: “Beardtongue”

Whenever I teach schoolchildren about the symbiotic relationship between plants and pollinators, I show penstemons as the perfect example of a flower hummingbirds frantically search for because it has deep, nectar-rich tubes. Similarly, when I am searching for a hardy, long blooming perennial for a planting design, I reach for penstemons.

Please keep reading to learn why the hummingbirds and I use Penstemon.

Photography by Britt Willoughby Dyer for Gardenista.

Above: Penstemon ‘Raven’ is a good choice for floral arrangements with its dramatic purple flowers and long-lasting habit as a cut flower.

I’d like to begin by thanking the plantain family for giving us some pretty amazing flowers including foxgloves, snapdragons, and penstemon. With more than 300 species, there is a variety of Penstemon every garden theme, design, location, and size.

Penstemon is a herbaceous perennial that characteristically has slender leaves and showy spikes of tubular flowers, in a range of mostly saturated colors including pink, white, purple, red, and occasionally yellow.

In North America, penstemons are used frequently in xeriscape or rock garden designs because many are native to desert areas and can handle the harsh, dry conditions while also providing a colorful impact. But Penstemon also looks right at home in a cottage garden when mixed with perennials such as cosmos, hydrangeas, and roses.

Above: Penstemon’s tubular flowers are a rich source of nectar for pollinators

A few favorites include Penstemon ‘Midnight’, with dark purple flowers and deep green leaves (an evergreen variety) and Penstemon ‘Apple Blossom’, with large, trumpet-shaped, pink flowers with a white throat. It is very showy but short lived and needs to be replanted every three to five years.

Above: Penstemon ‘Sour Grapes’.

Cheat Sheet

  • Bloom time for Penstemon typically begins in late spring through early summer, so try combining with plants that start blooming in mid summer, such as coneflower and black-eyed Susan, to fill the gap.
  • In addition to hummingbirds, bees also adore the pollen and nectar; Penstemon is a smart addition to a pollinator or meadow garden.
  • Try planting penstemons in groups of three or five plants for a massed appeal (but avoid crowding them).

Above: Penstemon ‘Sour Grapes’ is a reliable repeat bloomer if deadheaded throughout the summer season.

Keep It Alive

  • Being prairie natives, penstemons like fast-draining soil. Sandy or rocky (not clay) is best, and they like to be watered deeply but infrequently once established.
  • Situate penstemons in full sun for a more upright and less saggy appearance.
  • While sounding fussy, penstemons prefer to be mulched with gravel (not bark) so their crowns don’t rot over the winter.
  • Penstemon ranges in height from 1 to 3 feet, depending on the species, and will perform best if the spent flowers are pruned to promote re-blooming and tidiness. Cut the entire plant to the ground in the spring.

Read more growing tips in Penstemon: A Field Guide to Planting, Care & Design in our curated guides to Perennials 101. See more of our favorite hardy perennials:

  • Perennials: A Field Guide to Planting, Design, and Care.
  • 10 Easy Pieces: Tough Perennials for City Gardens.
  • Native Perennials for a Shade Garden: 9 Favorites for Cold Climates.
  • 10 Garden Ideas to Steal from Superstar Dutch Designer Piet Oudolf.

Penstemon Care And Maintenance – How To Grow Beard Tongue Plants

Penstemon spp. is one of our more spectacular native plants. Found in mountainous areas and their foothills, the herbaceous species is a temperate zone darling and thrives in most areas of the western United States. Also called Penstemon beard tongue, the plant produces dozens of tubular flowers arranged on a tall stalk. Learn how to grow beard tongue plants and you will have the birds, bees and butterflies doing summersaults to get at the plentiful blooms and their sweet nectar.

Penstemon Beard Tongue Information

If you have gone hiking in areas of Mexico to western North America from May to August, you will have seen these attractive flowers. Penstemon plants are related to snapdragons and come in a variety of cultivated hues for the home gardener. The flowers are perfectly shaped to accommodate hummingbirds, who spend their nesting period at the Penstemon snack bar.

Each flower has five petals and they come in hues of lavender, salmon, pink, red and white. The stems are triangular and the leaves are arranged opposite

with grayish green tones. Several different species exist and more are in cultivation. The exact shape of the leaves varies in each cultivar of Penstemon plants. They may be oval or sword shaped, smooth or waxy.

Penstemon beard tongue is a commonly found perennial, which may also grow as an annual in chilly or excessively hot regions.

How to Grow Beard Tongue Penstemon

The best location for your Penstemon is in a full sun area with well draining soil. Penstemon care and maintenance is minimal if the site and moisture requirements are met. Poorly draining soils and freezing temperatures while the plant is still active are the biggest causes of plant mortality.

The perennial is remarkably tolerant of drought conditions and is a stalwart presence in even low nutrient soils. It has had to be adaptable to thrive in windy, exposed areas of mountain foothills.

You can grow Penstemon from seed. They begin as rosettes low to the ground before forming the characteristic flower stalk. Indoor sowing should begin in late winter. Seedlings are ready to transplant when they have a second set of true leaves.

Space Penstemon plants 1 to 3 feet apart and mix in a little compost at planting time to help conserve water and increase porosity.

Penstemon Care and Maintenance

Water the young plants at least once per week as they establish. You can reduce watering as the plant matures. Mulch around the plants to help protect the roots from winter’s cold and prevents spring weeds.

The flower spire will produce seed in late summer to early fall and the petals fall away from the seeds. In my opinion, the remaining seed head has interest and appeal and I leave them until the rain smashes them down or cut them in late winter to make way for new growth.

Penstemon beard tongue makes an excellent cut flower, which will last for at least a week. Go native and plant some Penstemon plants in your sunny perennial garden.

New gardener? Try Mexicali penstemons

It’s understandable why gardening with annual flowers is so popular – they bloom all summer long and are relatively easy to care for. But in order to produce all these flowers, most annuals need heavy amounts of water and fertilizer to stay looking so lush and beautiful. On the other hand, gardening with perennials (plants that die to the ground but come back every year) sometimes seems too complicated… they bloom at different times, they come in different sizes, and they last many years so planning ahead is even more important.

Where to start with perennials? For westerners, Mexicali penstemons may be great plants for beginning perennial gardeners (they’re great for most gardeners, actually!) because they bloom nearly all summer, are adaptable to a wide range of garden conditions but also do well in containers, and don’t need a lot of water to stay looking healthy and full. The added bonus is that they’re great pollinator plants, too!

Penstemons are one of the west’s most abundant native wildflower species. With over 250 species in North American, the greatest percentage of these are native to the west. Here’s a breakdown by state (courtesy American Penstemon Society):

  • AZ- 43 species
  • CO – 62 species
  • ID- 46 species
  • MT- 32 species
  • NM- 42 species
  • NV- 45 species
  • UT-71 species
  • WY- 39 species

Mexicali penstemons are a group of penstemons with mixed parentage; hybrids of less-hardy Mexican species with large, showy flowers crossed with native American species that exhibit vigor and cold-hardiness. Bruce Meyers (White Salmon, WA) was one of the earliest and most prolific breeders of these beautiful and adaptable plants, and the first two penstemons introduced by Plant Select®, Red Rocks® and Pike’s Peak Purple®, came from some of Myers’ best selections.
Plants grow to be bushy, mounded plants that are ideal for mass plantings, drifts, raised beds, perennial borders, rock gardens or naturalistic gardens. They begin blooming in early summer in earnest, and will often bloom sporadically through August. Flowers are tubular, often with white-striped throats. Once pollinated, most will set seed which can be left intact to self-sow in the garden, or removed (deadheaded) to encourage further blooms.

Wildlife benefits: Mexicali penstemons attract bees, moths and butterflies. Plants are also considered deer-resistant.

Growing tips: Though adaptable to a wide range of conditions, they do best in well-drained, loamy soils with moderate water. All need at least 6 hours of sun a day to produce full plants with strong flowers.

At a glance: Penstemon x mexicali. Watch the video here.

Red Rocks®: Rosy-red flowers with white throat

    • Pike’s Peak Purple®: Violet-purple flowers with white throat
    • Shadow Mountain®: Lavender-blue flowers with white throat and purple-red lines
    • Windwalker® Garnet: Reddish to purplish flowers with white throat
    • Carolyn’s Hope: rich pink buds fade to medium pink flowers with white throat
      *Funds raised through sales of Carolyn’s Hope will benefit breast Cancer research at University of Colorado Cancer Center. Watch the video Carolyn’s Hope: here.

Height: 12-18” tall
Width: 12-14” wide
Growth habit: clumping perennial
USDA Hardiness Zones: 4b-8
How to Use: containers, perennial borders, mixed flower beds, naturalistic gardens
Culture: Sunny spots with moderate to dry conditions in most soils

Thanks to Pat Hayward, Plant Select, for writing this piece.

  1. Richard Swearingen says:

    San Joaquin Vaiiey, Visalia.——- wondering about growing in pots ?
    Also would like different varieties and colors.
    Have 6 in 2.5 acre yard all same color, pink or nearly coral pink.
    Suggest other color options and availability.
    Local Nurseries/Lowe’s/Home Depot seem to have only pink color plants.
    Hope to hear from you.

    • Ross Shrigley says:

      The big box stores mostly carry the most common varieties of plants available. Plant Select promotes 5 varieties of Penstemon mexicali. The colors do not vary much from darker pinks, corals and light pinks with white accents. There is one that offers a shade of lavender, Shadow Mountain. Try a local garden center and you should find more varieties. Penstemons are great plants, try others for more unique colors like orange/yellow. Enjoy!

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