Penstemon Guide: How To ID, Plant and Grow Types of Beardtongues Flowers

Image Credit: Ejohnsonboulder²⁶

How To Identify Penstemon

Penstemon plants are very distinct and grow in specific ways.

You can learn to identify the various plant parts to help harvest Penstemon seeds in the wild where allowed by local law.

How To Identify Penstemon Leaves

The leaves of the Beardtongue plants are oval, growing in whorls at the base. As more leaves develop further up the stem, they become long and slender, reaching 8 to 25 cm long and 4 cm wide, depending on the variety.¹⁹

They grow in opposite pairs directly from the main stalk and can have smooth or toothed edges. Leaves are typically blue-green or greenish-gray.

(Penstemon Seed Image: Andrey Zharkikh³³)

Due to some varieties being evergreen or semi-evergreen, they are considered a vital food source for grazers like deer and antelope. The leaves also have high moisture content, which makes them fire-resistant in areas that sometimes experience wildfires.²⁰

How To Identify a Penstemon Flower

Out of the mat-like ground cover, the flowers grow on stems that are stiff and about half an inch thick. They can grow upward of 1 to 5 feet depending on the variety.

Penstemon flowers are funnel-shaped,¹³ often with contrasting colors or guides inside the funnels that direct the pollinators to the nectar. The blooms grow in clusters of 3 to 10 depending on the variety, with each cluster developing 2 to 10 flowers.

Each flower is 1 to 2 inches long and up to half an inch wide. The tubular blooms have two lips, the upper with 2 lobes and the lower having 3 lobes.

Each bloom will have 5 stamens; 4 fertile pairs and a central stamen. Each pair of fertile stamens has an anther sac that is about 2mm long with an S-shaped opening at the tip.

The central stamen is sterile and covered with fine hairs. It protrudes half an inch from the center of the flower, giving the plant its nickname, Beardtongue, and also providing pollinators a safe place to perch while gathering nectar.

How To Identify Penstemon Seeds

Flowers drop off leaving behind seed heads, dried capsules that are about half an inch long. They are closed at the ends, resembling tiny tulip heads.

Seeds are small and black or brown.

Steps For Growing a Penstemon From a Seed, Cutting, or Seedling

If you have a patch of Penstemons already on your property and you want to incorporate their beauty into other parts of your garden, you can grow new plants from seeds gathered at the end of the season, about 6 weeks after the flowers have bloomed.¹²

The blooms will have dropped off, leaving tiny tulip-shaped seed heads. Both the stems and seed heads should be brown and appear dry.

Using sharp shears or a knife, cut 5 inches below the seed head to remove the stem and seed head from the plant. Store the harvested seed heads upside down in a paper bag for about a week or so to make sure there is no residual moisture left in the stem.

After the seed heads are thoroughly dried, pinch the tips of the heads to rupture the capsule. Briskly shake the seed head into the bag.

The seeds should fall freely from the head into the bottom of the bag. Pour the contents of the bag through a kitchen sifter to remove the chaff from the seed head, this will make sure you are only preserving seeds and not other organic material you don’t need.

To help the seeds sprout, you need to use cold stratification to jumpstart the germination process.⁹ The natural way to do this is to sow seeds between December and February and then let nature do the work.¹⁰

When you plant your seeds, sow them in garden areas that get at least 6 hours of bright sunlight in the normal growing seasons. Gently loosen the soil and bury the seeds only one-quarter of an inch deep.

The ground will naturally freeze and thaw throughout the winter months and the seeds will absorb rainwater and begin to germinate in Spring. Plants grown from seeds typically do bloom until the following year.⁹

If you plan on planting your seeds in Spring, you can mimic this process in the refrigerator. Label a plastic Ziploc bag with the date and name of the seeds you are planting.

Fill the bag with water and let the seeds soak for 4 hours. Drain excess water from the bag and add in perlite, measuring about 50/50 ratio of seed mass to perlite.

Store the bag with the perlite/seed mixture in the fridge for 4 to 5 weeks. Check occasionally to make sure the mixture is somewhat moist and inspect seeds for signs of sprouting.

Once the seeds have sprouted, you can plant them in their final location after the threat of frost has passed. For the first 2 weeks, water the seedling 2 times a week, then fall back to watering weekly.

Once the seeds are established the watering needs for Penstemon plants is relatively low, so you will only need to water when it is unseasonably dry.

To propagate Penstemons through cuttings select a healthy portion of a mature plant. Measure down 5 inches below the tip of the plant and snip off the stem, just below a leaf node.

A leaf node is a small bump in the stem where a new leaf or stem has sprouted. Trim off the bottom leaves from the cutting.

For best results, dip the cut end into a rooting hormone to encourage root development and place the cutting into a pot or bag filled with sandy soil.

Keep the cutting in a warm place where it can get dappled sunlight. Mist the soil occasionally to keep the roots moist.

In about 3 or 4 weeks, the cutting should have begun to develop roots. Once the roots are half an inch long, you can move the new plant to its final location in the garden.

Follow the same watering guide for seedlings.

How To Create the Best Growing Conditions for Penstemon In Your Garden

Once your seedlings or cuttings have been established, you want to make sure you have the ideal setting for your new Penstemon plants. You may have questions about when to plant Penstemon for the best yield, how much sunlight does Penstemon need each day, and how long it takes to grow Penstemon in your garden.

The best time to plant Penstemon is in the spring, which allows the plant to develop strong roots and acclimate to the environment. These plants require 6 to 8 hours of bright sunlight for a proper display of blooms.

Brighter areas also encourage plants to grow upright. The soil should be sandy, and can even be rocky.

In their natural habitat, they grow amongst rocks, mountains, and prairies; the drier the soil, the better. You can use compost to amend the soil but avoid heavy manure.

Penstemons are great for drought areas or where water use is monitored. You only need to water the plants during unseasonably dry periods.

If you choose to fertilize, do so once a year, during the fall season.¹⁸ Fertilizers designed to encourage more blooms stress the plant and can shorten its lifespan.

It can take 1 year for newly cultivated seeds to harden enough to bloom. Penstemons self-seed or spread via rhizomes.

It will spread yearly and should be divided every 3 to 5 years to maintain overall health and appearance.¹⁴

Popular Penstemon Varieties

This North American native boasts an impressive 250 or more varieties.²¹ Colorado alone has 62 native types while Utah has over 73 subspecies.^21,22

They come in various colors and attract many types of bees, butterflies, and hummingbirds. While not an exhaustive list, there are some popular varieties listed below and how you might use them in your landscape gardening.

It is often called a False Foxglove so that consumers will not confuse it with the European Foxglove, a toxic plant in the same family. Although both blooms are tubular and appear similar, the Beardtongue has a central stamen covered in fine hairs; resembling a fuzzy tongue, thus its name.

Foxglove Beardtongue works well in rock gardens and perennial borders.

Its leaves are evergreen and lance-shaped. While most Penstemons prefer craggy or loose soils, this particular variety can tolerate heavier soils that may hold a little more moisture than usual.⁶

Use the Rocky Mountain variety in border gardens or as fillers in cottage-inspired landscapes.

It is also the only variety without a bearded stamen.²³ Although considered the showiest of the Penstemons, the shell leaf’s blooms are short-lived and therefore not used as a focal point in gardens.⁷

Ideally, it is planted together in large groupings or mixed in among companion plants in cottage garden themes.

It maintains its semi-evergreen leaves throughout most of the winter. This variety works well in clay soils or gardens where drainage may be an issue.

It also is the variety that blooms the longest, so it is ideal as a focal point or backdrop beyond shorter plants.

Its flowering stem is shorter than other varieties, only reaching 10 to 12 inches while its shrubby base is more compact, spreading outward to 12 or 18 inches.⁸

Unlike most Penstemons, its flowers are red or orange, and occasionally yellow. They appear in late spring to mid-summer.

6. Green Rising Penstemon

Amusingly enough, you will not find this variety in any greenhouse or growing in the wild. Instead, this version is available only in the Peaceful Meadow level of the Disney game Dreamlight Valley.¹¹

That’s right, Disney loved these unique flowers so much that they used them as important collectibles in their adventure game.

In the game, it’s used in several recipes and crafts and can be traded with other members in the game to build friendships or sold for Star Coins, the currency within the platform.

How To Choose Companion Plants for Growing Penstemon

When choosing companion plants, look for plants that compliment the Penstemon’s flowering stalks. Ozark Sundrops and Purple Poppy Mallow both have large blooms with flat petals that contrast the tubular blooms of the Penstemon.⁵

Coneflowers and Butterfly Weed are also attractive plants with different flowering heads that add visual interest.

(Image: Meatle³²)

Ornamental grasses and succulents also provide contrasting texture and shapes. Penstemons grow well in large groupings, so you will need to plan how far apart to plant Penstemon plants.

Because of their shrub-like appearance, it is suggested to give them 12 to 18 inches between each plant.¹

How To Stop Penstemon Disease and Control Common Pests

Penstemons are hardy plants but they are susceptible to a few diseases.¹³ Root rot is very common and is caused by overwatering.

Too much water in the soil compacts the soil around the roots, making it difficult to absorb nutrients from the soil. In essence, your plant is drowning.

Other fungal infections like powdery mildew, rust, and leaf spot can occur. Powdery mildew leaves a white powdery substance on the leaves.

Rust is identified by small raised orange or brown spots on the underside of the leaves. Leaf spot leaves brown or black spots on the plant’s leaves.

These spots may have a yellow ring around them.

To prevent Penstemon disease, it is important to properly assess your garden’s water retention levels and your watering habits. Avoid overwatering; instead, only water when your region is experiencing unseasonably dry stretches.

Also, make sure to water at the ground level, and avoid letting water rest on leaves. Fungal spores take advantage of this layer of moisture on the leaves to germinate and infect the plant.²⁴

Make sure that there is adequate airflow between your plants. This regulates temperatures in the garden to bring down excessive humidity that encourages fungal growth.

In most cases, you can simply remove the affected parts of the plants, however, you may need to treat them with fungicidal sprays in extreme situations. It’s important to also remove and treat ground coverings around the plants as spores can grow on organic materials in the soil and mulch.

Common pests of the Penstemon are aphids,¹³ snails, slugs, and spider mites. Aphids and spider mites are small insects that suck juices from the plant.

Symptoms may be yellowing leaves or distorted growth patterns. You can use sprays, like miticides or insecticidal soaps to combat infestations.

Sometimes aphids, snails, and slugs will respond well to natural pest control for Penstemon plants. Ladybugs eat aphids and can help control populations.

Using bait traps and barriers can help reduce the amount of snails and slugs in the garden as well.

These plants are highly adaptive and beginner-friendly to new gardeners. Planting Penstemon is an easy way to diversify their native gardens and create a buzzing garden full of life and color.

Frequently Asked Questions About Penstemon