Phacelia Tanacetifolia (fa-SEE-lee-uh, tan-uh-see-tee-FOO-lee-uh) is a flowering species of the Boraginaceae family, also known as the hydrophyllaceae and forget-me-not family.
It is also sometimes referred to as Phacelia Tanacetifolia Benth.
Native to northwestern Mexico and the southwestern United States in North America, the plant is found in abundance in the deserts of Southern California where it grows mainly on elevated sites.
It is also abundantly found in Southern and Central Oak Woodland, Chaparral, Coastal Sage Scrub, Bush Scrub, and Pinyon-Juniper Woodland.
The scientific name of the plant refers to its flowers and leaves.
The word Phacelia comes from the Greek word for bundle or cluster, referring to its flowers which grow in forms of clusters.
Tanacetifolia, on the other hand, means ‘leaves like Tanacetum’.
The common names of phacelia tanacetifolia also refer to its flowers and leaves:
- Purple tansy
- Blue tansy
- Lacy phacelia – referring to the shape of the leaves
- Lacy scorpion – weed
Phacelia tanacetifolia is called tansy, a common name for Tanacetum plants, due to the resemblance of their leaves.
Lacy Phacelia Care
Size & Growth
Lacy phacelia is a small annual herb plant, which only grows up to 39” – 40” inches.
The stems are erect, glandular, and succulent with very few to no branches.
They are also generally covered with small stiff hair.
The leaves are compound and hence, divided into several smaller leaflets, which are also cut deeply into toothed lobes.
This gives the leaves a lacy appearance, hence the common name lacy phacelia.
Flowering and Fragrance
The plant produces small bell-shaped flowers on long flower stalk with dense and hairy coiling cymes, in shades of lavender and blue.
The flowers are borne in terminal clusters in summer – the bloom time starts in March and typically lasts till May, but sometimes extends till June.
Each flower in the inflorescence features long whisker-like stamens.
The flowers are nectar-rich and hence, are highly attractive to honey bees.
Unlike most plants, the lacy phacelia flowers bloom in sequence, resulting in a long blooming period.
The mature inflorescences drop small wrinkled and pitted brown seeds.
Light & Temperature
Blue tansy grows best in full sun, but also tolerates partial afternoon shade.
It is not winter hardy and often dies at 18° degrees Fahrenheit (-8° C).
USDA Hardiness Zones 3 – 10.
Watering and Feeding
Lacy phacelia prefers dry soil, which means its watering requirements are not high.
It is also fairly drought tolerant.
Make sure to not overwater as standing water will affect the plant’s growth.
When growing in poor soil, add a balanced organic fertilizer to the soil before planting for better results.
Soil & Transplanting
Since purple tansy plant mainly grows in deserts, at high altitudes, in its natural habitat, it prefers gravelly or sandy soil.
It also required the soil to be dry and well-draining.
Do not plant in soil with poor drainage as the plant doesn’t grow properly in waterlogged soils.
Grooming and Maintenance
P. tanacetifolia is a low-maintenance plant and doesn’t need grooming or lots of care to grow.
However, since the plant self-seeds abundantly, you would need to deadhead the plant if you want to prevent self-seeding.
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How To Propagate Phacelia Tanacetifolia
Purple tansy can only be grown from seeds.
While seeds are easy to germinate, they should be kept in darkness for at least the first 24 hours, after sowing.
Darkness is critical for the germination of lacy phacelia seeds as they are photodormant.
Also known as negatively photoblastic, photodormant seeds need darkness to germinate.
Nick or scratch the seed cost, soak them overnight and then sow the seeds directly on top of the soil in their permanent location anytime from spring to fall.
Phacelia Tanacetifolia Pest or Diseases
Blue tansy is susceptible to soil-borne diseases, like Rhizoctonia solani and Sclerotinia minor.
To reduce the risk of these diseases, it is recommended to not grow tanacetifolia in rotation with the plants affected by any of these pathogens.
The plant is known and prized for its ability to attract a number of beneficial insects and pollinators, including honey bees and bumblebees.
This phacelia species also attract hoverflies, which are highly useful biological pest control agents.
Hoverflies are highly effective for eliminating a number of pests, including aphids.
All these qualities make this herbarium species a valuable insectary plant.
Lacy Phacelia Uses
The plant is widely grown all over the world as a cover crop and green manure, in agriculture, and as an ornamental and bee plant in landscapes.
It’s sometimes used as a winter cover.
Since the plant attracts bees and a number of other beneficial insects, it is a good choice for commercial gardens, such as honey bee gardens.
The beautiful flowers, pollen, and long blooming period also make the tanacetifolia plant a popular choice for crop fields and vineyards.
Due to their long vase life, phacelia flowers are also commercially used as cut flowers in floral arrangements.
People with sensitive skin may experience skin irritation with the phacelia plant.
Therefore, it is recommended to wear protective gloves when working with the plant, especially if you have sensitive skin.