Firecracker penstemon
Penstemon eatonii · Plantaginaceae
Stems of narrow, scarlet tubes, all facing one way, above leathery, dark green leaves in late spring.
- Size
- 2½ ft tall, 18 in wide
- Zones
- 4 to 9
- Light
- Full sun
- Flowers
- Mid May to late June
- Pets
- Not checked
- Job in a bed
- Accent
A bed built around firecracker penstemon
The planner designed this bed around firecracker penstemon 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 firecracker penstemon stands where it does.
The plants
- 1 Firecracker penstemon × 4, red
- 2 Heath aster 'Snow Flurry' × 4, white
- 3 Sea thrift × 3, white
- 4 False sunflower 'Summer Nights' × 3, yellow
- 5 Silver sage × 1, silver leaves
- 6 Little bluestem 'The Blues' × 8, tan
- 7 Star of Persia × 5, purple
- 8 Tulip 'Fusilier' × 12, red
Why this plant
- Nothing here is unique to it. Its leaf, flower shape and colour are all on the plan already. Its case rests on where it stands and when it performs.
Why here
- In the middle. At 2½ ft it stands ahead of little bluestem 'The Blues' (3 ft) without hiding it.
- A step in the back row. Next to little bluestem 'The Blues' (3 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 4 plants in 4 places. An accent is a punctuation mark: the repeat along the bed gives it rhythm.
Why now
- In flower for 7 weeks. From mid May to late June.
- Part of the bed's peak. With sea thrift and star of Persia in late May: 3 kinds at once. No week has more.
- One of two evergreens. They are what the bed has to show from November to March.
Planned as a cottage garden: 23 of the 23 plants (100%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. Hot colours (red and yellow) with purple as the cool note, and white and tan to calm things between them. Something is in flower for 28 weeks, from mid April to mid October.
The planner's own design check: 13 Excellent, 4 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 firecracker penstemon goes in a border
At 2½ ft it belongs in the middle of a bed. In the planner's ten height classes it is medium (24 in to 2½ ft).
Its job: accent. An upright plant used singly, like a punctuation mark, and repeated at intervals to give the bed rhythm.
A desert native that hummingbirds find at once. It needs very little water after its first year, and rots if given much. Suited to the dry West.
- Hummingbirds
- Dry western gardens
- Gravel and rock gardens
What to plant with firecracker penstemon
Plants recorded as good partners for it, and what each pairing does:
- Blue grama 'Blonde Ambition': takes over when it finishes, flowering from mid July; a low mound at the foot of its spires; happy in the same dry soil.
- Sunset hyssop: takes over when it finishes, flowering from mid July; happy in the same dry soil.
- Blue flax: in flower together for seven weeks, from mid May; low enough (18 in) to stand in front of it; happy in the same dry soil.
Questions about firecracker penstemon
Does firecracker penstemon need sun or shade?
Firecracker penstemon 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 firecracker penstemon grow in?
USDA zones 4 to 9. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does firecracker penstemon flower in my zone?
In zone 5 it flowers mid 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 4 | Late May to early July |
|---|---|
| Zone 5 | Mid May to late June |
| Zone 6 | Early May to late June |
| Zone 7 | Early May to late June |
| Zone 8 | Late April to late June |
| Zone 9 | Mid April 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 firecracker penstemon be planted?
16 in (40 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 18 in (45 cm), so a group knits into one patch.
It grows 2½ ft (75 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many firecracker penstemon plants do I need?
At 16 in apart, set out in staggered rows:
- 7 to fill 10 square feet (about 1 m²)
- 8 for a single row 10 ft (3 m) long
- 21 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 four in four groups.
What flowers after firecracker penstemon?
Firecracker penstemon is over by late June. These start as it finishes and carry the same spot on, so it never goes flat:
- Sunset hyssop: from mid July to mid September, 24 in tall (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.
What does firecracker penstemon look like in winter?
Firecracker penstemon keeps its dark green leaves all winter, so it is one of the plants that hold a bed together from November to March, when the perennials have gone.
More Penstemon
- Beardtongue 'Dark Towers' Penstemon 'Dark Towers'
- Beardtongue 'Husker Red' Penstemon digitalis 'Husker Red'
- Beardtongue 'Prairie Dusk' Penstemon 'Prairie Dusk'
- Foxglove beardtongue Penstemon digitalis
- Hairy beardtongue Penstemon hirsutus
- Large beardtongue Penstemon grandiflorus
- Pineleaf penstemon Penstemon pinifolius
- Rocky Mountain penstemon Penstemon strictus
In these guides
Zone guides: Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Perennial
- Size
- 2½ ft (75 cm) tall, 18 in (45 cm) wide
- Plant
- 16 in (40 cm) apart
- Height class
- Medium (24 in to 2½ ft)
- Place in the bed
- Middle
- Flowers
- Mid May to late June; upright spires; red
- Leaves
- Medium texture, evergreen; dark green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 4 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.