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Penstemon ‘Sour Grapes’ (Beardtongue)

Penstemon 'Sour Grapes' M. Fish , Penstemon 'True Sour Grapes', Beardtongue 'Sour Grapes', Penstemon 'Sour Grape', Penstemon hartwegii 'Sour Grapes'

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Penstemon 'Sour Grapes', Penstemon 'Sour Grapes' M. Fish , Penstemon 'True Sour Grapes', Beardtongue 'Sour Grapes', Penstemon 'Sour Grape', Penstemon hartwegii 'Sour Grapes'

Penstemon ‘Sour Grapes’ doesn’t disappoint with its unusual name or its unique aesthetic. This perennial plant, known for its distinct, dusky grape-purple flowers, doesn’t bear the typical Penstemon look, offering instead a more exotic, almost tropical appearance.

Penstemon ‘Sour Grapes’: An In-depth Look

Native: This variety isn’t a native species but rather a cultivated hybrid developed for its enhanced ornamental appeal and garden performance, a testament to the versatility and adaptability of the Penstemon genus.

Plant Type and Habit: ‘Sour Grapes’ is a semi-evergreen perennial with an upright, bushy clump-forming habit. Its growth pattern is moderately compact, with the plant’s energy devoted to showcasing a lavish display of flowers.

Size: ‘Sour Grapes’ maintains a manageable size, generally reaching about 24-36 inches (60-90 cm) in height and spreading approximately 18-24 inches (45-60 cm) wide. This controlled growth makes it a suitable candidate for various garden applications.

Flowers: The flowers are the main event, with their intriguing grape-purple coloration that seems to change under different light conditions, sometimes appearing more blue or gray. Their tubular shape and white-marked throats are a beacon for pollinators and a visual delight for gardeners.

Bloom Time: Expect a spectacular show from early summer into fall, especially in milder climates or with adequate deadheading.

Foliage: The foliage presents a glossy, bright green that forms a lovely contrast with the dark-toned flowers. Leaves are lance-shaped and arranged oppositely on the stem, contributing to the plant’s overall lush appearance.

Uses: ‘Sour Grapes’ is versatile, suitable for border plantings, container gardens, rock gardens, and as part of pollinator-friendly landscapes.

Award: Recipient of the prestigious Award of Garden Merit of the Royal Horticultural Society.

Hardiness: This plant boasts commendable hardiness, capable of thriving in USDA zones 7-10.

Pollinators: Penstemon is attractive to various pollinators, especially bees, and hummingbirds, drawn to their nectar-rich flowers.

Toxicity: Penstemons are not known to be toxic to humans or pets. However, it’s always prudent to prevent ingestion of any non-edible plants.

Deer and Rabbit: An added bonus is its resistance to deer and rabbits, a characteristic attributed to the texture and taste of the foliage that these animals generally find unappealing.

Drought: Once established, ‘Sour Grapes’ shows a good level of drought tolerance. While it prefers consistent moisture levels, it can endure short periods of dry conditions, a boon for gardeners in more arid climates.

Invasiveness: ‘Sour Grapes’ is not known for being invasive. It’s a well-behaved garden resident that stays within its allocated space, making it a reliable and predictable perennial option.

Penstemon Growing Tips

Light: Full sun (at least 6 hours of direct sun per day). Tolerates light shade.

Soil: Well-drained soil is crucial. Penstemons prefer rocky or sandy lean soils rather than rich garden loam. Avoid overly moist, poorly drained soils.

Water: Water well until plants are established. Once established, Penstemons tolerate some drought. Allow the soil to dry out between waterings. Over-watering or wet soils can lead to root rot.

Fertilizer: Penstemon plants generally do not require heavy fertilization and can thrive in relatively lean soil conditions. However, providing them with a light application of an organic fertilizer in the fall can help boost their growth and flowering potential.

Pruning: Deadhead spent flowers to encourage continuous blooming. Cut back plants in late autumn or early spring to promote vigorous 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.

Propagation: Propagate by softwood cuttings in early summer or semi-ripe cuttings in midsummer.

Pests and Diseases: No serious pest or disease issues, but watch for slugs, snails, and nematodes. Fungal diseases can occur in overly wet conditions; ensure good air circulation and avoid overhead watering to prevent issues like powdery mildew, leaf spot, and root rot. Rust can cause small, rust-colored pustules on leaves and stems, leading to defoliation and stunted growth.

Penstemon: How to Grow and Care with Success


Properly growing Penstemon ensures robust, vibrant blooms and foliage, enhances garden biodiversity by attracting pollinators, prevents disease, and maintains plant health. Thriving plants provide longer-lasting beauty and environmental benefits, contributing positively to local ecosystems and the aesthetic value of your landscape.

Requirements

Hardiness 7 - 10
Heat Zones 7 - 10
Climate Zones 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Perennials
Plant Family Plantaginaceae
Genus Penstemon
Common names Penstemon, Beardtongue
Exposure Full Sun, Partial Sun
Season of Interest Summer (Early, Mid, Late),
Height 2' - 3' (60cm - 90cm)
Spread 1' - 2' (30cm - 60cm)
Spacing 18" - 24" (50cm - 60cm)
Maintenance Low
Water Needs Low
Soil Type Chalk, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Well-Drained
Characteristics Showy, Plant of Merit, Semi-Evergreen
Tolerance Drought, Deer
Attracts Bees, Hummingbirds
Garden Uses Beds And Borders, Patio And Containers
Garden Styles Gravel and Rock Garden, Informal and Cottage
How Many Plants
Do I Need?
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Penstemon (Beardtongue)
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Alternative Plants to Consider

Penstemon pallidus (Pale Beardtongue)
Penstemon pseudospectabilis (Desert Beardtongue)
Penstemon parryi (Parry’s Beardtongue)
Penstemon heterophyllus ‘Electric Blue’ (Foothill Beardtongue)
Penstemon ‘Evelyn’ (Beardtongue)
Penstemon ovatus (Eggleaf Beardtongue)

Recommended Companion Plants

Salvia (Sage)
Achillea (Yarrow)
Echinacea (Coneflower)

Find In One of Our Guides or Gardens

35 Flowering Shrubs That Thrive in Full Sun
42 Best Perennial Flowers and Plants to Brighten Your Garden Every Season
Penstemon and Pollinators: A Harmonious Dance in the Garden
Thriving in Thirst: Colorful Penstemons for Water-Wise Landscapes
Penstemon: How to Grow and Care with Success
Penstemon (Beardtongue)
For the Love of Bees: Best Flowers to Attract them to Your Garden
How to Cultivate a Thriving Bee-Friendly Garden
Best Flowers to Attract Hummingbirds
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.
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Requirements

Hardiness 7 - 10
Heat Zones 7 - 10
Climate Zones 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Perennials
Plant Family Plantaginaceae
Genus Penstemon
Common names Penstemon, Beardtongue
Exposure Full Sun, Partial Sun
Season of Interest Summer (Early, Mid, Late),
Height 2' - 3' (60cm - 90cm)
Spread 1' - 2' (30cm - 60cm)
Spacing 18" - 24" (50cm - 60cm)
Maintenance Low
Water Needs Low
Soil Type Chalk, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Well-Drained
Characteristics Showy, Plant of Merit, Semi-Evergreen
Tolerance Drought, Deer
Attracts Bees, Hummingbirds
Garden Uses Beds And Borders, Patio And Containers
Garden Styles Gravel and Rock Garden, Informal and Cottage
How Many Plants
Do I Need?
Explore Great Plant Combination Ideas
Penstemon (Beardtongue)
Not sure which Penstemon (Beardtongue) to pick?
Compare Now

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