Alphabetical Plant Listing

Penstemon serrulatus (Cascade Penstemon)

Serrulate Penstemon, Serrulate Beardtongue, Cascade Penstemon, Cascade Beardtongue, Coast Penstemon, Coast Beardtongue, Penstemon diffusus


Penstemon serrulatus (Cascade Penstemon) is a semi-evergreen subshrub with several ascending to erect stems boasting dense, one-sided clusters of deep blue to purple, trumpet-shaped flowers in early to late summer. The blossoms attract bees, hummingbirds and numerous pollinators. Arising from a woody base, the stems are clad with glossy, oval to lance-shaped, dark green leaves that are conspicuously toothed on the margin. Cascade Penstemon is native to moist woods and rock faces of the humid transition zone west of the Cascade Mountain crest. It is considered to be one of the most adaptable penstemons, and is cold tolerant.

  • Grows up to 12-24 in. tall (30-60 cm) and 10-12 in. wide (25-30 cm).
  • Performs best in full sun in moist, well-drained soils. The soil should not be too dry.
  • Provides a charming impact in beds and borders, cottage gardens or along ponds and streams.
  • Keep an eye out for slugs, snails, aphids, gray mould, powdery mildew, fungal leaf spot.
  • Deadhead after flowering.
  • Take softwood cuttings in early summer or semi-ripe cuttings in midsummer. Divide in spring or propagate by seed in late winter or spring.
  • Native to Alaska, Oregon, Washington and British Columbia.

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Requirements

Hardiness 3 – 9
Heat Zones 1 – 9
Plant Type Shrubs
Plant Family Penstemon - Beardtongues
Exposure Full Sun
Season of Interest Summer (Early,Mid,Late)
Height 1' – 2' (30cm – 60cm)
Spread 10" – 1' (25cm – 30cm)
Spacing 12" (30cm)
Water Needs Average, High
Maintenance Low
Soil Type Chalk, Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained
Characteristics Showy, Semi-Evergreen
Native Plants United States, Alaska, Pacific Northwest, Oregon, Washington
Attracts Birds, Butterflies, Hummingbirds
Garden Uses Beds and Borders, Ponds and Streams
Garden Styles Informal and Cottage

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By Andrey Zharkikh, Brewbooks, Flickr

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.


Requirements

Hardiness 3 – 9
Heat Zones 1 – 9
Plant Type Shrubs
Plant Family Penstemon - Beardtongues
Exposure Full Sun
Season of Interest Summer (Early,Mid,Late)
Height 1' – 2' (30cm – 60cm)
Spread 10" – 1' (25cm – 30cm)
Spacing 12" (30cm)
Water Needs Average, High
Maintenance Low
Soil Type Chalk, Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained
Characteristics Showy, Semi-Evergreen
Native Plants United States, Alaska, Pacific Northwest, Oregon, Washington
Attracts Birds, Butterflies, Hummingbirds
Garden Uses Beds and Borders, Ponds and Streams
Garden Styles Informal and Cottage

Great Plant Combination Ideas with Penstemon - Beardtongues

Guides with Penstemon - Beardtongues

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