Firecracker penstemon is a perennial wildflower that has vivid orange-red blooms throughout the year. Here’s everything you need to know about growing and caring for this southwest desert native.
Firecracker penstemon (Penstemon eatonii) is a native wildflower that doubles as a popular evergreen landscape perennial.
The leaves are unremarkable rosettes of leathery green leaves, but they are not the reason people use this as a landscape plant.
They grow it for the brilliant scarlet red flower stalks that grace this plant several months of the year. Here in Arizona it is equally at home in Flagstaff as it is in Phoenix. In Tucson, it often blooms from February through June, although I’ve seen it bloom all year long.
Firecracker penstemon is one of the largest, most robust, drought-tolerant penstemons in the southwest. It’s also one of the most widespread.
It thrives in an unusually diverse range of environments. It can be found growing in low and high deserts, forests, and open plateaus of Arizona, California, Colorado, Idaho, Nevada, New Mexico, Utah, and Wyoming.
In the wild, it grows in areas with as little rain as 5 inches and as much as 40.
The flowers attract butterflies and hummingbirds. Deer and rabbits usually leave this plant alone.
Why I Like This Plant
- Stunning scarlet flowers
- Low-maintenance southwest native
- Easy to start from seed
- Reseeds but not aggressively
- Attracts butterflies and hummingbirds
Things to Watch Out For
Firecracker penstemon is a short-lived perennial, only living 3-6 years. But once established it reseeds, although not so much as to be a nuisance. As new plants pop up, they eventually outgrow and replace the older plants.
Compared to some other native penstemons, firecracker can slow to start and take a few years to start blooming.
If you want to control their spread, simply remove the seed stalks as soon as the blooms fade to prevent reseeding.
Optimal Growing Conditions
If you’re thinking of adding firecracker penstemon to your garden, you need to find a suitable place that will keep your plants looking good and coming back every year.
Here are the main factors to keep in mind.
Temperature
No matter where you live, temperature should not be a concern. It grows in USDA Hardiness Zones 4 – 10 and can handle the heat of Phoenix and cold down to -10℉.
Sun Exposure
While firecracker penstemon can grow in full sun, it benefits from partial shade in the summer, ,especially in the hottest areas. However, if plants get too much shade they can get leggy.
Size and Growth Rate
Firecracker penstemon grows moderately fast. The foliage forms rosettes usually 2 by 2 feet, but the flower stalks can shoot up to 3 feet tall.
Soil
Firecracker penstemon is not particular about soil and can grow in sandy, rocky, or clay soil, provided it’s well-draining.
It’s a good plant to place on a berm where good drainage is assured.
Firecracker Penstemon:
The Essentials
| Common Names | Firecracker penstemon, firecracker beardtongue |
| Scientific Name | Penstemon eatonii |
| Origin | Sonoran, Mojave, Great Basin Deserts |
| Plant Type | Perennial wildflower |
| USDA Zones | Zones 4 – 10 |
| Cold Hardiness | To -10℉ |
| Flower Color | Orange-red |
| Flower Season | Spring |
| Mature Size | 2’ high x 2’ wide |
| Growth Rate | Moderate |
| Sun Tolerance | Full, part sun |
| Water Needs | Low |
| Pests & Diseases | Root rot if overwatered Mealy bug, aphids |
| Garden Friendly | No thorns, non-toxic, non-allergenic |
| Wildlife | Attracts butterflies, bees, birds, hummingbirds Deer, rabbit resistant |
How to Plant
The rule of thumb when planting any perennial in the desert is to dig a hole twice as wide as the root ball but no deeper. Amending the soil is not recommended. Counterintuitively, backfilling with the same native soil you just dug up helps your plant develop a stronger root system.
Firecracker penstemon needs room to grow so plant it approximately 3 feet from other plants. When plants are crowded they are prone to getting mealybugs and aphids.
When to Plant
It is best to plant penstemon in the fall, but ironically, they are hard to find at nurseries then. Spring is the second best time to plant and plants are more readily available.
Growing Firecracker Penstemon: Seed vs Transplants
I rarely have the patience to start perennials from seed, but I make an exception for firecracker penstemon.
While firecracker penstemon is a fairly popular landscape plant in the southwest, you may have trouble finding it when you are ready to plant. I rarely see them in the fall (the best time to plant) but sometimes find them at local nurseries in the spring (the second best time to plant).
You can buy seeds or gather them, provided you do it responsibly. Sow in the fall and if they like where you’ve planted them, you’ll be rewarded with seedlings the following spring.
Please see A Guide to Collecting and Growing Sonoran Desert Wildflowers. This brochure published by the Native Arizona Plant Society will tell you everything you need to know about collecting wildflower seeds.
Do not dig up wild plants!
They almost certainly will not survive and you will
have deprived the area of next year’s seedlings.
How to Care for Firecracker Penstemon
This section is short because these plants need little care.
How to Water
While your plant could live on rainfall alone — as it does in the wild — it will do better if it gets watered 1-2 times per month, either from rainfall or irrigation.
Should You Fertilize?
Native wildflowers don’t need fertilizer since they are well-adapted to thrive and bloom in native soil.
Pruning
Firecracker penstemon needs no pruning other than cutting the flower stalk after it has bloomed. Deadheading flowers in May or June can promote more blossoms.
If you want it to reseed or plan to collect seeds, leave at least one flower stalk in place until the seed pods have turned brown and dried. Then you can easily collect the seeds.
If plants get leggy or woody, you can cut them back any time to rejuvenate.
Plant Lover Facts
Native Americans had many traditional uses for firecracker penstemon. The Navajo used it to treat snake bites and burns, as a disinfectant, to stop wound bleeding, and for digestive issues. The Shoshoni used it to wash and heal burns.
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for 15 years.
