How to Grow Phacelia Plants

Gardener's HQ Guide to Growing Heliotrope and California Bluebell

Phacelia plants are hardy annuals that reach from 30 to 60 cm (1 to 2 feet) in height.

Phacelia have a bush nature and carry heart shaped leaves; sometimes toothed.

They bloom in the summer when they carry blue or lavender bell shaped flowers.

Some of the common names for Phacelia include California Bluebell, Heliotrope, and Wild Heliotrope.

Phacelia sericea
Phacelia sericea – Silky Phacelia by Brewbooks; creative commons.

Phacelia incana
Phacelia incana (Hoary phacelia) by Matt Lavin; creative commons.

Phacelia Plant Growing and Care Guide

Common Names: Heliotrope, Wild Heliotrope, Scorpionweed, California Bluebell, Wild Canterbury Bells. Phacelia: Sand dune; Southern Sierra; Stinging; Weasel; Caterpillar; Alpine; Hiddenflower; Skyblue.
Family: Phacelia.
Life Cycle: Hardy annual. Hardy perennial.
Height: 8 to 30 inches (20 to 75 cm).
Native: Americas.
Growing Region: Zones 3 to 10.

Flowers: Summer.
Flower Details: Blue, violet, white. Bell-shaped.
Foliage: Herbaceous. Lanceolate. Oval. Cordate. Toothed.

Sow Outside: 1/4 inch (6 mm). Before the last frost. In warm areas can be sown in early autumn. Spacing 4 to 16 inches (10 to 40 cm). Germination time: two to four weeks in the dark. Temperature 55°F (13°C).
Sow Inside: No
Requirements: Full sunlight. Good drainage. Soil pH 6.5 to 7. Average soil. Can survive in dry soils. Pinch tips.

How to Grow California Bluebell, Heliotrope and other Phacelia Plants in the Garden

It is best to grow Heliotrope and California bluebells outdoors from seeds. Sow about 6 mm (1/4 inch) deep, before the last frost of spring.

California bluebells, Heliotrope, and other Phacelia plants like to grow in sunny areas of the garden and likes a soil of pH 6.5 to 7.

The soil type is not too important. It typically takes from two to four weeks for the seeds to germinate once the temperature reaches 12 to 16 degrees Celsius (54 to 61°F).

Smaller species of Phacelia should be grown about 15 cm (6 inches) apart, and larger varieties spaced at 25 to 30 cm apart (10 to 12 inches).

Caring for California Bluebell - Phacelia

Once growing strongly young California Bluebells / Phacelia plants should be pinched back at the tips to facilitate branching.

Phacelia species are tolerant of dry weather so only need to be watered in extremely dry conditions.

Common Questions

How many members does the Phacelia genus contain?

The Phacelia genus contains fromt 150-200 species of annuals and perennials.

Do Phacelia members make a good garden or landscaping plant?

Yes, Phacelia plants, often known as Scorpionweeds, are appreciated in gardens for their lovely bell-shaped flowers and their value to pollinators. Some species are also used as green manure or cover crops.

Which Phacelia species are most frequently grown by gardeners?

Phacelia tanacetifolia, commonly known as Lacy phacelia or Blue tansy, is a popular choice among gardeners for its blue-purple flowers and fern-like foliage.

Are Phacelia plants fragrant?

While some Phacelia species may have a mild scent, they are not generally known for their fragrance.

What is the perfect location to grow Phacelia?

Phacelia plants prefer full sun to part shade and well-drained soil. They can tolerate a range of soil types, including poor soils.

Is Phacelia invasive in the USA, if so in which states?

Some species of Phacelia, such as Phacelia cicutaria or caterpillar phacelia, are considered invasive in certain regions of the USA.

How do I remove Phacelia plants from my garden?

To remove Phacelia plants, pull up the whole plant, ensuring all roots are removed. They can self-seed, so removing flowers before they set seed can help control their spread.


Phacelia is a genus in the Boraginaceae family comprising annuals and perennials known for their beautiful and unique inflorescence. They're often grown for their abundant nectar, attracting pollinators like bees.

These plants prefer a location with full sun to light shade and well-drained soil. Seed planting usually occurs in the spring. With their bee-friendly characteristics and beautiful blooms, they make a great addition to wildflower gardens, meadows, and borders.

I hope that you enjoyed this guide on how to grow Phacelia plants. You may also enjoy the following Gardener's HQ growing guides: How to grow Bluebells, California Fuchsia, California Pitcher Plant, and Mertensia plants.