Desert bluebell is an unmistakable, vivid blue wildflower. Once established in your garden, it will come back year after year. Here’s everything you need to know about growing and caring for this Sonoran Desert native.
Desert bluebell (Phacelia campanularia) is a delightful wildflower with vivid blue bell-shaped flowers. Since most of the spring-blooming desert flowers are yellow or orange, they really pop.
But you don’t have to take a hike or stumble upon them in the wild — they can easily be grown as an annual in desert gardens.
They need full sun and, provided we’ve had some winter rain, can survive on rainwater alone. In their natural environment, they survive on as little as 3” of rain per year.
Besides being the truest blue flower you’ll ever have in your garden, desert bluebells are also one of the easiest plants to take care of. It needs virtually no maintenance. Once you’ve sown your seeds, you can let nature take care of them.
And once you’ve had your first “crop” they usually reseed and come back year after year.
Desert bluebells provide nectar for native bees and are hosts for numerous moths and butterflies.
Why I Like This Plant
- Gorgeous cobalt blue flowers (yes, they really are this color!)
- Readily reseeds, plant once and you can have them forever
- No maintenance — simply sow and wait for them to grow (watering optional)
- Seeds are easy to collect, so you can sow them elsewhere or give them to friends
Things to Watch Out For
If you’re looking for an annual that gives you many months of flowers (i.e., marigolds, zinnias, or petunias), be aware that desert bluebells are not like that. They bloom for a few weeks, usually in March and April, and then die back.
The leaves of desert bluebells have small hairs that many people find irritating. Some people will get itchy or develop a mild rash whereas others suffer a serious reaction akin to poison ivy.
Optimal Growing Conditions
If you’re thinking of adding desert bluebells 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 key factors to keep in mind.
Temperature
As a short-lived annual, their preferred temperature range is between freezing and about 80℉. Once the temperatures start reaching the 90s℉ they’ll start losing their vigor.
Sun Exposure
Desert bluebells like full sun — and I mean real, death-star desert sun. These diminutive plants look like they might thrive in woodlands, but they are tough desert survivors and there is no such thing as too much sun for them.
Size and Growth Rate
Once they sprout, they grow fast, flowering in about 8 weeks. When full grown, they reach a size of 1’ by 1’.
Soil
Desert bluebells are tolerant of any well-drained soil type. In the wild, you’ll often find them growing in dry sandy washes and along roadsides.
Other Location Considerations
With their brilliant blue flowers, desert bluebells are certain to attract attention. So be sure to plant them where children can’t pick them or pets won’t nibble on them.
If you live in a community with an HOA or you want your yard to look more manicured and tidy rather than wild and free-form, remove plants as soon as they start dying back.
Desert Bluebells:
The Essentials
| Common Name | Desert bluebell |
| Scientific Name | Phacelia campanularia |
| Origin | Mojave, Sonoran deserts |
| Plant Type | Annual wildflower |
| USDA Zones | Zones 9 – 10 |
| Cold Hardiness | To 20℉ |
| Flower Color | Cobalt blue |
| Flower Season | Spring |
| Mature Size | 1’ high x 1’ wide |
| Growth Rate | Fast |
| Sun Tolerance | Full sun |
| Water Needs | Low |
| Pests & Diseases | None |
| Cautions | Irritating hairs, contact dermatitis |
| Wildlife | Attracts native bees Butterfly & moth larval host Deer, rabbit resistant |
Growing Desert Bluebells: Seed vs Transplants
Since desert bluebells are short-lived annuals, they’re usually grown from seed. However, if you do happen to plant a transplant, you can consider it your “starter” plant that should self-seed and naturalize in your yard.
As a true wildflower, growing from seed couldn’t be easier.
Last fall I sprinkled a packet of seeds on top of my landscape gravel and then watered them in. You don’t want to bury them since the seeds need light to germinate. This spring I was pleasantly surprised with at least a dozen plants.
You can buy seeds or gather them, provided you do it responsibly. 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 and planting wildflower seeds.
You can learn more about growing wildflowers from seed in our article The Easy Way to Grow Desert Wildflowers.
Do not dig up wild plants!
They almost certainly will not survive
and you will have deprived the area of next year’s seedlings.
When to Plant
If you’re starting with transplants, plant as soon as you can find them, usually in late winter. If you’re sowing seeds, the best time is in the fall, October through November.
How to Care for Desert Bluebells
This section is short since you really don’t have to do much to care for your desert bluebells.
They don’t need fertilizer or trimming, unless you want to remove spent plants in the spring after they’re done flowering.
How to Water
Rainwater should provide your seeds and plants with all the water they need. If you experience prolonged dry spells, you can give them a squirt every few weeks.
Plant Lover Facts
Desert bluebells goes by an array of common names, mostly sticking with the blue bell theme — except desert scorpionweed. What a horrible-sounding name for a truly lovely plant.
- Arizona bluebells
- bluebells
- California bluebells
- desert bluebells
- desert bells, desertbells
- desert scorpionweed
- desert Canterbury bells
Desert bluebells are a southwest native found in both the Sonoran and Mojave deserts, yet somehow have reportedly naturalized in places as far afield as northern Canada and West Virginia.
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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.
