Deno’s GardenMy Garden

Penstemon pachyphyllus

Thick-leaf Penstemon · Thickleaf Beardtongue

Family PlantaginaceaeGenus Penstemon

A blue-violet flower with purple lines running down a pale throat and a yellow-bearded tongue, beside thick blue-green leaves.
FlowerAndrey Zharkikh from Salt Lake City, USACC BY 2.0

About the plant

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

Habit
perennialPlants of the World Online
Habit
Perennial, Forb/herbPLANTS Database
Flower
Blue, purpleWikipedia
Native range
Arizona, Nevada, UtahGBIF Backbone Taxonomy

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; Wikipedia — Wikipedia contributors; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

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.

75% germination in 7–35 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. pachyphyllus germ. 70D GA-3(75% in 1-5 w), 70D(none), and 40(56% in 5- 10w).
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

Difficulty Moderate Rated by us, not by the source.

Start around January 25, 2027 for a May 3 last frost.

  1. Cold moist stratification

    Temperature: 40°F 4°C

Germination happens during step 1, in 70 days.

56% germination in 35–70 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. pachyphyllus germ. 70D GA-3(75% in 1-5 w), 70D(none), and 40(56% in 5- 10w).
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.

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

Add to My Garden

View species page