Large beardtongue
Penstemon grandiflorus · Plantaginaceae
Waxy, blue-grey leaves that clasp the stem, and above them the largest flowers of any penstemon: lavender bells as long as a thumb.
- Size
- 3 ft tall, 12 in wide
- Zones
- 3 to 9
- Light
- Full sun
- Flowers
- Late May to late June
- Pets
- Not checked
- Job in a bed
- Accent
A bed built around large beardtongue
The planner designed this bed around large beardtongue when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, full sun. It chose the other plants from the 715 that suit those conditions and its dry soil, and says below why large beardtongue stands where it does.
The plants
- 1 Large beardtongue × 5, lavender
- 2 Candytuft × 5, white
- 3 Sedum 'Lidakense' × 19, pink
- 4 New England aster 'Alma Pötschke' × 3, pink
- 5 Leadplant × 1, purple
- 6 Red valerian × 3, pink
- 7 Star of Persia × 4, purple
- 8 Netted iris × 12, blue
Why this plant
- The only bold leaves here. The rest are fine and medium. A change of leaf keeps plants distinct when nothing is in flower.
- The only lavender.
Why here
- Anchors a back corner. At 3 ft it is one of the taller plants here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to leadplant (2½ ft) and New England aster 'Alma Pötschke' (3½ ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 5 plants in 3 places. An accent is a punctuation mark: the repeat along the bed gives it rhythm.
Why now
- In flower for five weeks. From late May to late June.
- Part of the bed's peak. With red valerian and star of Persia in late May: 3 kinds at once. No week has more.
Planned as a cottage garden: 29 of the 36 plants (81%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. The flowers stay on the cool side of the palette: lavender, pink, purple, blue and white. The back corners are held by large beardtongue and New England aster 'Alma Pötschke', the tallest plants on the plan.
The planner's own design check: 11 Excellent, 6 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where large beardtongue goes in a border
At 3 ft it belongs in the middle of a bed. In the planner's ten height classes it is medium tall (2½ to 3 ft).
Its job: accent. An upright plant used singly, like a punctuation mark, and repeated at intervals to give the bed rhythm.
A showpiece of the sand prairies. It is short-lived, needs sand or gravel, and seeds itself where it is happy. The blue leaves are worth having on their own.
- Sandy and gravel soils
- Prairie planting
- Blue foliage
What to plant with large beardtongue
Plants recorded as good partners for it, and what each pairing does:
- Little bluestem: its blue-green leaves are a setting for the flowers, before and after; fine leaves against its bold ones; happy in the same dry soil.
- Blue grama 'Blonde Ambition': takes over when it finishes, flowering from mid July; fine leaves against its bold ones; a low mound at the foot of its spires.
- Butterfly weed: medium leaves against its bold ones; happy in the same dry soil.
Questions about large beardtongue
Does large beardtongue need sun or shade?
Large beardtongue grows in full sun (6 or more hours of direct sun a day).
It wants dry, sharply drained soil, on the lean side, with no feeding, and little watering once settled.
What zones does large beardtongue grow in?
USDA zones 3 to 9. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does large beardtongue flower in my zone?
In zone 5 it flowers late May to late June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 3 | Mid June to early July |
|---|---|
| Zone 4 | Early June to early July |
| Zone 5 | Late May to late June |
| Zone 6 | Late May to late June |
| Zone 7 | Mid May to late June |
| Zone 8 | Early May to late June |
| Zone 9 | Early May to mid June |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should large beardtongue be planted?
12 in (30 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.
It grows 3 ft (90 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many large beardtongue plants do I need?
At 12 in apart, set out in staggered rows:
- 12 to fill 10 square feet (about 1 m²)
- 11 for a single row 10 ft (3 m) long
- 38 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one at a time, repeated along the bed at intervals; a slender one reads better as a clump of three.
In the bed above, the planner used five in three groups.
What flowers after large beardtongue?
Large beardtongue is over by late June. These start as it finishes and carry the same spot on, so it never goes flat:
- Butterfly weed: from late June to early August, 24 in tall, to stand in front of it and cover its fading stems (a recorded partner).
- Blue grama 'Blonde Ambition': from mid July to mid October, 2½ ft tall (a recorded partner).
- Black-eyed Susan: from mid July to mid September, 24 in tall, to stand in front of it and cover its fading stems.
What does large beardtongue look like in winter?
Large beardtongue holds some of its leaves into winter, more in a mild year or a sheltered spot, and they look tired by March. Cut the old ones off as new growth starts.
More Penstemon
- Beardtongue 'Dark Towers' Penstemon 'Dark Towers'
- Beardtongue 'Husker Red' Penstemon digitalis 'Husker Red'
- Beardtongue 'Prairie Dusk' Penstemon 'Prairie Dusk'
- Firecracker penstemon Penstemon eatonii
- Foxglove beardtongue Penstemon digitalis
- Hairy beardtongue Penstemon hirsutus
- Pineleaf penstemon Penstemon pinifolius
- Rocky Mountain penstemon Penstemon strictus
In these guides
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Perennial
- Size
- 3 ft (90 cm) tall, 12 in (30 cm) wide
- Plant
- 12 in (30 cm) apart
- Height class
- Medium tall (2½ to 3 ft)
- Place in the bed
- Middle
- Flowers
- Late May to late June; upright spires; lavender, pink
- Leaves
- Bold texture, semi-evergreen; blue-green, silver
- Shape
- Upright, self-seeding
- Hardy in
- USDA zones 3 to 9
- Light
- Full sun
- Soil
- Lean, dry and sharply drained
- Water
- Low
- Feeding
- None needed
- Family
- Plantaginaceae
Not yet checked against an outside reference: its figures rest on general horticultural knowledge. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.