Description & Overview

Penstemon grandiflorus, Large Beardtongue as it’s commonly known, is native to the dry prairies of Wisconsin. Many bees love this species, and watching them wriggle their way up the tube of Penstemon’s flowers will put a smile on anyone’s face, especially after a long winter. Mint-green basal leaves add a nice contrast to other plants in the garden and give this perennial an overall special somethin’. If you are looking for a plant with beautiful flowers that bloom in the spring, prefer dry soil, and attract pollinators, then look no further.

You may also know this plant as Large-flowered Beardtongue, Large Penstemon, Canterbury Bells, or Wild Foxglove.

Core Characteristics

Category: Perennial

Wisconsin Native: Yes

USDA Hardiness Zone: to zone 3

Mature Height: 24-36 inches

Mature Spread: 12-24 inches

Growth Rate: Fast

Growth Form: Upright

Light Requirements: Full Sun

Site Requirements: Sandy, dry soil

Flower: Lavender, tubular, 24"-36" stalk

Bloom Period: May, June

Foliage: Blue-Green Ovate Leaves

Fall Color: N/A

Urban Approved: No

Fruit Notes: Capsule containing many seeds

Suggested Uses

Large Beardtongue has large blue-green leaves, up to six inches long, in its first year. In the plant’s second year, another unique rosette of leaves is produced, followed by a three-foot flowering stalk sporting lavender/white alternating flowers with bilateral symmetry. Anyone would stop a walk through the garden to kneel down and take a good look. It is unique and beautiful.

Restoration: As a native resident of our local prairies, Large Beardtongue would be a great addition to any prairie restoration project. This plant will thrive in an open, dry, full sun location.
Pollinator Garden: Large Beardtongue adds pollinator power and a nice pop of color to any wildflower garden in the early summer. Its unique, large, mint-green basal leaves add contrast when planted in a mixed bed.
Rock Garden: As a lover of well-draining, dry soil, Large Beardtongue would do very well in a rock garden.

Penstemon grandiflorus, Large Beardtongue as it's commonly known, is native to the dry prairies of Wisconsin. Many bees love this species and watching…
Penstemon grandiflorus, Large Beardtongue as it's commonly known, is native to the dry prairies of Wisconsin. Many bees love this species and watching…

Wildlife Value

Bumblebees, as well as several long-tongued bees, Syrphid flies, and skippers, readily visit many Penstemon species. Notably, Osmia distincta, a type of Mason Bee, relies heavily on Penstemon as they are most active in the early summer months, coinciding with the bloom time of many Penstemon species. At this point, it is worth talking about the structure of the flowers for a moment so that we can all fully appreciate the way Penstemons have evolved with bees to ensure pollination.

The petals of Penstemon flowers are fused, creating two lips, one on top and one on the bottom with the bottom lip serving as a sort of landing pad, while the top lip acts as a low roof. The fusion of the petals creates a closed tubular shape baited deep inside with delicious nectar. When the bee lands on the bottom lip, not only is it hit with the scent of the nectar but also with visual cues in the form of contrasting streaks leading down the tunnel that can only be seen in UV (the way a bee sees). The bee then follows these cues, wiggling its way inside the tube, at which time the back of her abdomen brushes against a pollen-producing anther that is fused to the top of the structure, resulting in a sort of forced pollination as the bee makes its way from flower to flower. So cool, right?!

Birds also enjoy what Penstemon has to offer. Hummingbirds can be seen visiting the flowers. Songbirds and sparrows of the dry prairies of Wisconsin feed on the seeds.

Maintenance Tips

The flower stalk can be cut off after the flowers are spent if keeping the garden neat and tidy is a priority. This will leave only the basal leaves which still offer a contrasting color that would stand out in a garden. Or… leave the stalks up and let the flowers go to seed to help sustain the birds through the winter!

Large Beardtongue may not do well if planted in typical garden soil as it often holds too much moisture for too long. Do not overwater as it will lead to root rot. It grows a big taproot, and so is well adapted to dry soil. As such, avoid poorly draining, clay soils as this will likely lead to root rot.

Spread seeds to propagate.

Penstemon grandiflorus, Large Beardtongue as it's commonly known, is native to the dry prairies of Wisconsin. Many bees love this species and watching…
Penstemon grandiflorus, Large Beardtongue as it's commonly known, is native to the dry prairies of Wisconsin. Many bees love this species and watching…

Pests/Problems

Occasional leaf spot and rust may occur but can be lessened by watering the base of the plant and avoiding overhead watering.

Short-lived, but do not let this deter you from planting. Use seed capsules to propagate so that it appears year after year!

Leaf Lore

Native American tribes used leaves and roots to treat several ailments. Roots were chewed and applied against sore teeth to relieve toothaches as well as used to cure stomach and chest pains. Leaves were made into a tea to treat fever, as well as pounded to release juices that were believed to treat rattlesnake bites.

Name: Penta is derived from the Greek word meaning, “five.” Stemon is a Greek word referring to the stamens, of which all Penstemons have five. The epithet grandifloras means “large-flowered”.

Companion Plants

Penstemon grandiflorus, Large Beardtongue as it's commonly known, is native to the dry prairies of Wisconsin. Many bees love this species and watching…
johnsons nursery menomonee falls horticulturist julia feltes

Written by Julia Feltes