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Penstemon speciosus

Royal Beardtongue · Royal Penstemon · Showy Penstemon

Family PlantaginaceaeGenus Penstemon

Pale pink-lilac bells with white streaked throats, hanging in a row down one side of an upright stem.
FlowerKurt Stüber [1]CC BY-SA 3.0

About the plant

What it is and where it grows — not part of any germination protocol.

The plant

Habit
perennialPlants of the World Online
Habit
Perennial, Forb/herbPLANTS Database
Height
2.5 ft75 cmPLANTS Database
Flower
BluePLANTS Database
Blooms
Mid SummerPLANTS Database
Native range
California, Idaho, Nevada, Oregon, Utah, WashingtonGBIF Backbone Taxonomy

Growing conditions

Sun
Shade tolerance: HighPLANTS Database
Soil
Adapted to coarse, medium textured soilsPLANTS Database
Soil pH
6.4-8.0PLANTS Database
Moisture
Moisture use: LowPLANTS Database
Watering
Drought tolerance: HighPLANTS Database

Toxicity is noted only where a source states it. No note here is not a finding of safety.

Sources: Plants of the World Online — Royal Botanic Gardens, Kew; PLANTS Database — USDA NRCS; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

Worth knowing

  • The royal penstemon is food for the caterpillars of two butterflies, the variable checkerspot and the anicia checkerspot. Wikipedia: Penstemon speciosus

This source reports two treatments. Both are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Low Rated by us, not by the source.

Start around March 1, 2027 for a May 3 last frost.

  1. Gibberellic acid soak

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing. Then 35 days to germinate.

70% germination in 14–35 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. speciosus ssp kennedyi germ. 70D GA-3(70% in 2-5 w) and none in 40 or 70D.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 2

DerivedN. C. Deno, 1993

  1. Cold moist stratification

    Temperature: 40°F 4°C

Germination happens during step 1.

0% germination.

Nothing germinated at 40.

This source doesn't state how long step 1 lasts.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. speciosus ssp kennedyi germ. 70D GA-3(70% in 2-5 w) and none in 40 or 70D.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. Quoted exactly. Every value on this card comes from this record; the step names come from a fixed list.

How each step is done, in Deno’s words, and what Verified and Derived mean.

Germination trials

Readers’ own records of sowing this species, published after review. Share your trial · All trials

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