Create Your Garden

Penstemon (Beardtongue)

Penstemon, also known as beardtongue, encompasses a diverse group of plants highly regarded in the gardening world.

Penstemon, Beadtongue, Hummingbird

What is Penstemon?

Penstemon, also known as beardtongue, encompasses a diverse group of plants highly regarded in the gardening world.

Native: Penstemons are native to North America, with the highest diversity in the western United States. However, certain species extend into the northern regions of the Midwest and Canada, and some are native to the eastern United States. Their habitats are equally diverse, ranging from open plains and desert regions to alpine mountain zones.

Penstemon belongs to the Plantaginaceae family, which includes common flowers such as snapdragon and foxglove. There are approximately 250-280 species, making it one of the largest genera of flowering plants native to North America.

Description: Penstemon plants are recognized for their striking tubular flowers, each with a distinct, often bearded, fifth stamen. They exhibit a wide range of colors, from serene blues and purples to vibrant reds and pinks, often with contrasting throat markings.

Growth Habit: Most penstemons are herbaceous perennials, meaning they die back in winter and regrow in spring. However, the genus also includes some subshrubs and shrubs, particularly in its southern range. Penstemons generally have an upright growth habit with a clumping form. They produce dense spikes or loose racemes of flowers atop stems that can be either leafy or bare, depending on the species.

Size: Penstemon plants vary widely by species, ranging from compact forms only a few inches tall to robust species that can reach several feet in height.

Flowers: Penstemon flowers are tubular and bilaterally symmetrical, with five prominent stamens, one of which is usually bearded – the characteristic that gives them the common name “beardtongue.” The colors span nearly the entire spectrum and attract a host of pollinators.

Blooming Season: While blooming times can vary among species, most penstemons flower in late spring to early summer, with blooms lasting several weeks. Some species have a secondary bloom in late summer or early fall.

Penstemon venustus, Venus penstemonPenstemon venustus, commonly known as charming penstemon or Venus penstemon, is native to the western United States

Fruit: Penstemons produce small seed capsules containing numerous tiny seeds after flowering. Gardeners sometimes use these for propagation.

Foliage: Foliage among Penstemon species varies, but leaves are generally lanceolate to ovate, with entire or serrated margins. Some species feature evergreen foliage, while others are deciduous.

Hardiness: Penstemons are hardy plants, with different species adapted to different USDA zones. Most are suited for zones 4-9, though this can vary, especially with species native to higher elevations or southern latitudes.

Uses: Penstemons are widely used in ornamental gardening due to their beautiful flowers and ease of care. They’re also used in habitat restoration projects, native plant gardens, and xeriscaping due to their drought tolerance and low maintenance requirements.

Pollinators: The tubular flowers of penstemons are magnets for pollinators, particularly hummingbirds and various species of bees, which are attracted to the nectar and vibrant colors.

Toxicity: Penstemons are generally considered non-toxic to humans and animals, making them safe additions to gardens.

Deer and Rabbit: Most penstemons are resistant to browsing by deer and rabbits due to the slightly bitter taste of their foliage.

Drought: Many penstemon species are remarkably drought-tolerant, particularly those native to desert or prairie environments, making them suitable for water-wise gardens.

Invasiveness: While penstemons can self-sow, they are typically not considered invasive and are often encouraged in native plantings.

Guide Information

Hardiness 3 - 10
Climate Zones 1, 1A, 1B, 2, 2A, 2B, 3, 3A, 3B, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Perennials, Shrubs
Plant Family Plantaginaceae
Genus Penstemon
Exposure Full Sun, Partial Sun
Season of Interest Spring (Mid, Late)
Summer (Early, Mid, Late)
Fall
Height 1' - 6'
(30cm - 180cm)
Spread 1' - 5'
(30cm - 150cm)
Maintenance Low
Water Needs Low, Average
Soil Type Loam, Sand, Clay
Soil pH Acid, Neutral, Alkaline
Soil Drainage Well-Drained
Characteristics Showy, Cut Flowers
Native Plants United States, New Jersey, New Hampshire, New York, Pennsylvania, Rhode Island, Vermont, Delaware, Connecticut, Massachusetts, Maryland, Maine, Southeast, Pacific Northwest, Rocky Mountains, Midwest, Southwest, Northeast, Wisconsin, Michigan, Ohio, Kansas, Illinois, Indiana, Nebraska, North Dakota, Missouri, South Dakota, Iowa, Minnesota, Idaho, Oregon, Washington, South Carolina, Tennessee, Virginia, West Virginia, Arkansas, Alabama, North Carolina, Georgia, Kentucky, Louisiana, Mississippi, Texas, New Mexico, Nevada, Arizona, Oklahoma, Wyoming, Colorado, Montana, Utah
Tolerance Deer, Drought, Dry Soil, Rocky Soil, Rabbit
Attracts Bees, Butterflies, Hummingbirds
Landscaping Ideas Wall-Side Borders, Patio And Containers, Beds And Borders
Garden Styles City and Courtyard, Coastal Garden, Gravel and Rock Garden, Informal and Cottage
Penstemon pinifolius (Pine-needle Beardtongue)
Penstemon ‘Apple Blossom’ (Beardtongue)
Penstemon ‘Garnet’ (Beardtongue)

Why Should I Grow Penstemon?

Growing Penstemon in your garden, landscape, or natural area offers a multitude of benefits:

Aesthetic Appeal: With their vibrant, tubular flowers, Penstemons add a splash of color and visual interest to any garden. The variety in species offers a range of colors, sizes, and forms, allowing for diverse and creative garden designs.

Attract Pollinators: Penstemons are known for their ability to attract a variety of pollinators. Their nectar-rich flowers are favorites for bees, butterflies, and hummingbirds, which can help maintain the health of your garden and promote biodiversity.

Drought Tolerance: Many Penstemon species are particularly drought-tolerant, making them excellent choices for low-water gardens and xeriscaping. Once established, they require minimal water, suiting areas with water restrictions or those wishing to conserve water.

Ease of Care: Generally, Penstemons are low-maintenance plants. They don’t require complex soil amendments and, once established, can thrive with minimal care, making them suitable for both new and experienced gardeners.

Castilleja miniata, Penstemon cardwelliiPenstemon cardwellii & Castilleja miniata. Mount St Helens National Park, Washington State

Erosion Control: Certain species of Penstemon have a growth habit that makes them effective for erosion control. They can stabilize soil on slopes and in areas prone to erosion.

Adaptability: Penstemons can thrive in a variety of soil types and climatic conditions, making them adaptable to various environments. There’s likely a Penstemon that can thrive in your specific region and soil conditions.

Native Plant Benefits: Using native Penstemons enhances the natural ecosystem, providing food and habitat for local wildlife. Native plants often have a better survival rate in their local environment and contribute to the biodiversity and ecological health of their region.

Seasonal Interest: Many Penstemons have an extended blooming season, providing color and interest in the garden for a longer period compared to other perennials. Some even have attractive foliage or seed pods for fall and winter interest.

Versatility: Penstemons work well in various garden types, from formal and casual flower beds to wildflower meadows and naturalistic landscapes. They can be used as border plants, specimens, or ground covers, depending on the species.

Low Pest and Disease Issues: Penstemons are typically resistant to many pests and diseases, especially when planted in conditions that suit their growth needs.

Penstemon heterophyllus ‘Electric Blue’ (Foothill Beardtongue)
Penstemon digitalis (Foxglove Beardtongue)
Penstemon mensarum (Grand Mesa Beardtongue)

Popular Penstemon Varieties

There are numerous varieties of Penstemon, each with unique characteristics. Here are brief descriptions of some main varieties:

Penstemon digitalis (Foxglove Beardtongue): A remarkable perennial prized for its tubular white flowers and statuesque presence in the landscape. It is suitable for the perennial border, the natural landscape or prairie reconstructions.

Penstemon eatonii (Firecracker Penstemon): Recognizable by its bright scarlet-red flowers, this variety is extremely drought-tolerant and a hummingbird magnet.

Penstemon heterophyllus (Foothill Beardtongue): Offers electric blue to violet flowers, often with contrasting foliage. Drought-tolerant and vibrant, it’s a favorite for xeriscapes.

Penstemon palmeri (Scented Penstemon): Known for its large, fragrant, pale pink to rose-colored flowers, Penstemon palmeri, or Palmer’s penstemon, is a native desert species, attracting hummingbirds and providing a striking vertical element with its tall, erect stems.

Penstemon speciosus (Royal Penstemon): Boasts charming wands of royal blue flowers in late spring to mid-summer. It is a good plant for water-wise landscaping, rock gardens, desert gardens, and other ornamental plantings.

Penstemon spectabilis (Showy Beadtongue): Showcases vivid purple-blue flowers on erect spikes, a beacon for pollinators. It’s valued for drought resistance, making it a staple in water-wise gardens and native Californian landscapes.

Penstemon strictus (Rocky Mountain Beardtongue): Showcases deep violet-blue flowers. Hardy and beautiful, it’s native to the meadows and slopes of the Rocky Mountains.

Penstemon ‘Husker Red’: Popular for its white flowers and unique, reddish-purple foliage, providing dramatic color contrast in gardens.

Penstemon ‘Dark Towers: A hybrid prized for its pink flowers and dark wine-purple foliage, taller and more disease-resistant than ‘Husker Red’.

 

Penstemon palmeri (Scented Penstemon)
Penstemon speciosus (Royal Penstemon)
Penstemon strictus (Rocky Mountain Beardtongue)

Garden Design with Penstemon

Incorporating Penstemon in your garden design can add remarkable texture, color, and an attraction for wildlife like birds and butterflies. Here’s how you can design your garden with Penstemon:

Color Palette: Penstemons bloom in a variety of colors including pink, red, white, blue, and purple. Determine your garden’s color scheme first; then select the variety of Penstemon that complements it. For a warmer palette, go for reds and pinks. For cooler tones, choose blues and purples.

Borders and Beds: Penstemon plants are excellent for borders and flower beds, as they can add height and structure, especially the taller varieties. Plant them in groups or drifts for visual impact, or use them as a repeating element to create rhythm and coherence in your garden design.

Wildlife Attraction: Because they’re known for attracting pollinators, place Penstemons in a sunny spot where you can observe the birds, bees, and butterflies that they draw. They’re especially known for attracting hummingbirds.

Container Gardening: Some compact varieties of Penstemon are well-suited to container gardening. This is a great way to adorn patios, balconies, and entryways. Ensure the containers have adequate drainage and are large enough to support the plant’s growth.

Summer borders, Garden Ideas, Border ideas, Perennial Planting, Perennial combination, Prairie Planting, Echinacea Paradoxa, Yellow Coneflower, Penstemon barbatus, Red Beardtongue, Clary Sage, Stipa TenuissimaEchinacea paradoxa (Yellow Coneflower, Penstemon barbatus (Red Beardtongue), Salvia sclarea (Clary Sage)

Rock Gardens and Xeriscaping: Drought-resistant Penstemons are perfect for rock gardens and xeriscaping. Their ability to thrive in less-than-ideal soil makes them a fantastic low-maintenance choice for these types of landscapes.

Companion Planting: Penstemon plants are highly compatible with other perennials. Consider planting them with complementary species such as lavender, salvia, or ornamental grasses for contrasting textures. 

Vertical Interest: Taller varieties of Penstemon can add vertical interest to your garden. They can act as a colorful backdrop for shorter plants or be used as focal points.

Cottage Gardens: Penstemon works well in a cottage garden setting, offering a blend of shapes and colors that contribute to the overall charming effect. They can be mixed with traditional cottage garden plants like roses, foxgloves, and phlox.

Sustainable Landscaping: Native varieties of Penstemon are an excellent choice for sustainable landscapes due to their low water needs and attraction of beneficial wildlife.

Companion Plants for Penstemon

Achillea (Yarrow)
Echinacea (Coneflower)
Lavandula angustifolia (English Lavender)
Nepeta (Catmint)
Rosa (Rose)
Salvia (Sage)
Sedum (Stonecrop)
Rudbeckia hirta (Black-Eyed Susan)
Gaillardia (Blanket Flower)

Growing and Caring for Penstemon

Growing and caring for Penstemon involves understanding their needs for sunlight, soil, water, pruning, and general maintenance. Here’s how you can ensure your Penstemon thrives:

Planting Location: Most Penstemon species prefer a location with full sun but can tolerate partial shade, especially in hotter climates. Around 6-8 hours of sunlight is ideal. Ensure good air circulation around the plants to prevent fungal diseases.

Soil: Penstemons thrive in well-drained soil. They can tolerate a wide range of soil types, including sandy, loamy, or rocky soils, but they generally don’t do well in heavy clay or overly rich soils.

Watering: These plants are drought-tolerant once established but will need regular water until they reach that point. Water deeply when the soil is dry to the touch, but allow the soil to dry out slightly between waterings. Overwatering or constant soil moisture can lead to root rot, a common issue with Penstemons.

Fertilization: Penstemons generally do not require much fertilizer. Overfeeding can lead to lush foliage but fewer flowers and can also make the plants leggy and weak. However, providing them with a light application of an organic fertilizer in the fall can help boost their growth and flowering potential.

Pruning and Deadheading: Regular deadheading (removing spent flowers) can encourage a longer blooming period. In late winter or early spring, prune back any dead or damaged stems to make way for new growth. 

Mulching: Mulching Penstemon can help regulate ground temperature and suppress weed growth. Choose a mulch that does not hold water. Use organic materials like shredded bark, compost, or pine straw. Avoiding direct contact with the stems to prevent rot and pest issues.

Winterizing: While many Penstemons are perennials, they can be sensitive to harsh winters, especially in very cold climates. Mulching around the base can help protect the roots. In colder zones, consider winter protection such as straw or a frost cloth, especially for less hardy varieties.

Propagation: Penstemons can be propagated by division, cuttings, or seeds. Division should be done in the spring or fall. Cuttings can be taken in late spring or early summer, while seeds are often sown in the fall or spring, depending on the climate.

By paying attention to these aspects of their care, you can enjoy the beauty of Penstemon flowers in your garden for many years. Remember, the specific needs can vary slightly between different species and cultivars, so always check the requirements for the particular type of Penstemon you are growing.

Penstemon digitalis ‘Blackbeard’ (Beardtongue)
Penstemon Cha Cha Lavender (Beardtongue)
Penstemon ‘Midnight Masquerade’ (Beardtongue)

Pests and Diseases

Like all plants, Penstemon can be susceptible to certain pests and diseases, although they’re generally considered hardy and trouble-free when their basic growing conditions are met. Here are some of the potential issues you might encounter:

Pests

Aphids: These small, sap-sucking insects can cluster on the undersides of leaves or on stems, potentially transmitting diseases and causing distortion or stunted growth. They can be controlled by rinsing with water, introducing beneficial insects like ladybugs, or using insecticidal soaps.

Spider mites: These tiny mites can be hard to see but cause damage by sucking plant juices, often indicated by yellowing leaves and fine webbing. Mitigate them by ensuring good air circulation, occasional misting to increase humidity, or using miticides if necessary.

Slugs and Snails: These pests are attracted to the moist environment around the plants and can chew holes in the leaves or flowers. Barriers, baits, and manual removal at night can help manage their populations.

Diseases

Root rot: Usually a result of overwatering or poor drainage, symptoms include wilting, yellow leaves, and stunted growth. Prevent it by ensuring well-drained soil and avoiding overwatering.

Powdery mildew: This fungal disease causes a white powdery coating on leaves, stems, and flowers, often occurring in high humidity and moderate temperatures. Improve air circulation, avoid wetting the foliage, and treat with fungicides if necessary.

Rust: This fungal issue presents as orange or brown pustules on the undersides of leaves. Remove affected leaves, avoid overhead watering, and apply a fungicide if severe.

Leaf Spot: This is characterized by brown or black spots on the leaves, often with a yellow halo. Various fungi cause it and can be mitigated by ensuring good air circulation and avoiding overhead watering.

Penstemon ‘Sour Grapes’ (Beardtongue)
Penstemon Red Riding Hood (Beardtongue)
Penstemon ‘Stapleford Gem’ (Beardtongue)

Frequently Asked Questions

Can you overwater Penstemon?

Yes, you can overwater penstemons. They are drought-tolerant plants that prefer well-drained soils. Overwatering can lead to root rot, a condition that occurs when the plant’s roots sit in water for too long, depriving them of necessary oxygen. Symptoms of overwatering include yellowing leaves, wilting, and a stunted or mushy base. It’s best to let the soil dry out between waterings to prevent these issues.

Should I deadhead my Penstemons?

Yes, it would be best if you deadheaded penstemons. Deadheading, or removing spent flowers, encourages the plant to produce more blooms and extends the flowering season. It also prevents the plant from using its energy to produce seed, focusing more on vegetative growth and future flowers.

Why is my Penstemon floppy?

Penstemon stems can become floppy for several reasons. Overwatering, too much fertilizer, or not enough sunlight can lead to lush but weak, leggy growth. Lack of pruning can also result in long, overgrown stems that can’t support themselves. To prevent floppiness, ensure your penstemon is planted in well-drained soil, gets plenty of sunlight, and is not over-fertilized. Regular pruning, including cutting back in the early spring, can help promote bushier, more stable growth.

Should Penstemon be staked?

Staking penstemons is not usually necessary, as they are generally upright plants. However, if they are planted in a particularly windy area, have been over-fertilized leading to excessive growth, or if they’re flopping due to any of the reasons mentioned above, staking might be necessary to prevent breakage and keep them upright. Use a stake that is the height of the plant minus the flower head and tie the stem to the stake loosely with garden twine. Stakes should be inserted when the plants are small to avoid root damage. Regular pruning to encourage bushier growth can reduce the need for staking in the future.

Garden Examples

A Splendid Fall Border Idea with Penstemon, Asters and Grasses
A Fabulous Duo: Salvia ‘Caradonna’ and Penstemon ‘Rich Ruby’
A Fabulous Duo: Rose ‘The Mayflower’ and Penstemon ‘Stapleford Gem’
A Prairie Planting Idea with Echinacea, Penstemon and Salvia
A Prairie Planting Idea with Echinacea, Penstemon and Eryngium
An Eye-Catching Spring Path with Alliums, Tulips and Beardtongue
While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.

Guide Information

Hardiness 3 - 10
Climate Zones 1, 1A, 1B, 2, 2A, 2B, 3, 3A, 3B, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Perennials, Shrubs
Plant Family Plantaginaceae
Genus Penstemon
Exposure Full Sun, Partial Sun
Season of Interest Spring (Mid, Late)
Summer (Early, Mid, Late)
Fall
Height 1' - 6'
(30cm - 180cm)
Spread 1' - 5'
(30cm - 150cm)
Maintenance Low
Water Needs Low, Average
Soil Type Loam, Sand, Clay
Soil pH Acid, Neutral, Alkaline
Soil Drainage Well-Drained
Characteristics Showy, Cut Flowers
Native Plants United States, New Jersey, New Hampshire, New York, Pennsylvania, Rhode Island, Vermont, Delaware, Connecticut, Massachusetts, Maryland, Maine, Southeast, Pacific Northwest, Rocky Mountains, Midwest, Southwest, Northeast, Wisconsin, Michigan, Ohio, Kansas, Illinois, Indiana, Nebraska, North Dakota, Missouri, South Dakota, Iowa, Minnesota, Idaho, Oregon, Washington, South Carolina, Tennessee, Virginia, West Virginia, Arkansas, Alabama, North Carolina, Georgia, Kentucky, Louisiana, Mississippi, Texas, New Mexico, Nevada, Arizona, Oklahoma, Wyoming, Colorado, Montana, Utah
Tolerance Deer, Drought, Dry Soil, Rocky Soil, Rabbit
Attracts Bees, Butterflies, Hummingbirds
Landscaping Ideas Wall-Side Borders, Patio And Containers, Beds And Borders
Garden Styles City and Courtyard, Coastal Garden, Gravel and Rock Garden, Informal and Cottage
Compare All Penstemon (Beardtongue)
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Penstemon (Beardtongue)

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