Desert bluebell is an unmistakable, vivid blue wildflower. Once established in your garden, this eye-catching annual will come back year after year. Here’s everything you need to know about growing and caring for this native ot the Mojave and Sonoran Deserts.
Desert bluebell (Phacelia campanularia) is a delightful wildflower with vivid blue, bell-shaped flowers. They really “pop” against the sea of yellow and orange spring-blooming desert flowers.
But you don’t have to take a hike or stumble upon them in the wild to behold their beauty. They can easily be grown as an annual in desert gardens.
They need full sun and, provided you’ve had some winter rain, can survive on rainwater alone. In their natural environment, they survive on as little as 3” of annual rainfall.
Besides being the truest blue flower you’re likely to 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. They are largely deer and rabbit resistant.
Why I Like This Plant
- Gorgeous cobalt blue flowers
- Readily reseeds
- No maintenance — sow & grow (watering optional)
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.
If you live in an HOA where certain standards must be met, you will probably need to promptly remove the spent plants which look rather weed-like.
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
This short-lived annual prefers temperatures between freezing and about 80℉. Once the temperature starts reaching 90℉, they start losing their vigor — flowers fade and leaves die back.
Sun Exposure
Desert bluebells like full sun — we’re talking 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.
Here’s a volunteer that grew next to the sunniest spot in my yard — against a south-facing wall that gets zero shade. It grew over 2 feet across and was the happiest bluebell I’ve had.
Size and Growth Rate
Once seeds sprout, they grow fast, from seedling to flowering in about 8 weeks. When full grown, they typically reach a size of one foot tall and wide, but can grow larger.
Soil
In the wild, you’ll often find desert bluebells growing in dry sandy washes and along roadsides. In gardens, they are tolerant of any well-drained soil type.
Other Location Considerations
With their brilliant blue flowers, desert bluebells are certain to attract attention. But be sure to plant them where curious kids or pets can’t touch them, since touching them can be irritating.
If you live in a community with an HOA, you might want to grow these in your backyard rather than front, since they look untidy during their dying out phase. I grow them in my backyard so that I can let them die naturally and go to seed.
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 | Supports pollinators 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. I simply sow seeds on top of my landscape gravel and then water them in. You don’t want to bury them since the seeds need light to germinate.
The seedlings are easy to spot in the spring since they arrive early and have a purple tinge that doesn’t look like any other wildflower. The stems are reddish-purple, and the leaves have distinctive purple edges and veins.
You can buy seeds or gather them, provided you do so 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 rarely 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 desert bluebells really don’t need any care.
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 to emulate the rain you should have had.
They don’t need fertilizer. They don’t need trimming. Unless you have a truly wild garden, you’ll probably want to remove spent plants in the spring after they’re done flowering.
Plant Lover Facts
Desert bluebells go by an array of common names, mostly sticking with the bluebell 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 desert natives that grow in Arizona and California. Yet somehow, they have reportedly naturalized in places as far afield as northern Canada, Germany, and New York!?! Don’t believe it? (I didn’t either.) Check Kew Royal Botanic Gardens’ distribution map. It’s a mystery.
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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 over 15 years.
Photo Credits
Stickpen, Public domain, Wikimedia Commons