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Native Plant Database

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Houstonia caerulea (Azure bluet)
Bransford, W.D. and Dolphia

Houstonia caerulea L.

Azure bluet, Quaker-ladies, Bluets

Rubiaceae (Madder Family)

Synonyms: Hedyotis caerulea

USDA Symbol: HOCA4

USDA Native Status: Native to U.S.

This small, delicate perennial is found growing in compact tufts, 8 in. high. The plants may cover broad expanses. Tiny flowers are pale blue with yellow centers, tubular, four-lobed, solitary, and terminal. Spatula-shaped leaves occur in basal rosettes. Stem leaves are small and the stems are unbranched.

This lovely, delicate, flowering plant is often found in striking patches of light blue. The Star Violet (H. pusilla), to 4 (10 cm) high, has a tiny purple flower and occurs in fields and open woods from South Dakota east to Maryland and south to Florida and Texas. A tall southern species, 6-16 (15-40 cm) high, Large Houstonia (H. purpurea), has 3-5, ribbed, opposite, ovate leaves, and white or pink flowers. It occurs from Nebraska northeast to Maine and south to Florida and Texas. These and certain other Houstonia species have sometimes been placed in the genus Hedyotis.

 

From the Image Gallery

Plant Characteristics

Duration: Perennial
Habit: Herb
Flower:
Fruit:
Size Class: 0-1 ft.

Bloom Information

Bloom Color: Blue
Bloom Time: Apr , May , Jun , Jul

Distribution

USA: AL , AR , CT , DC , DE , GA , IL , IN , KY , LA , MA , MD , ME , MI , MO , MS , NC , NH , NJ , NY , OH , PA , RI , SC , TN , VA , VT , WI , WV
Canada: NB , NS , ON , QC
Native Distribution: N.S. to Ont. & WI, s. to GA, LA & AR; more common eastward
Native Habitat: Deciduous woods; moist meadows; clearings
USDA Native Status: L48(N), CAN(N), SPM(I)

Growing Conditions

Light Requirement: Part Shade
Soil Moisture: Moist
Soil pH: Acidic (pH<6.8)
Soil Description: Moist soils.
Conditions Comments: Bluets do well when grown among grasses of lawns and fields, but care should be taken not to mow them before they have set seed. Bluets are sometimes planted as a delicate, attractive addition to rock gardens.

Benefit

Conspicuous Flowers: yes

Propagation

Description: Plant seeds outside as soon as ripe or store, stratify and sow in the spring. Seeds should be sown at a shallow depth. These seedlings will germinate the first year and flower the second. Propagation by division is accomplished by digging the plants in
Seed Collection: Approximate collection date in northern U.S.: Late Jun. to mid Jul.
Seed Treatment: Moist stratification.
Commercially Avail: yes

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is either on display or available from the following:

Delaware Nature Society - Hockessin, DE
Longwood Gardens - Newark, DE
* Available Online from Wildflower Center Store

Bibliography

* The Midwestern Native Garden: Native Alternatives to Nonnative Flowers and Plants An Illustrated Guide (2011) Adelman, Charlotte and Schwartz, Bernard L.

Search More Titles in Bibliography

Recommended Species Lists

Find native plant species by state. Each list contains commercially available species suitable for gardens and planned landscapes. Once you have selected a collection, you can browse the collection or search within it using the combination search.

View Recommended Species page

Additional resources

USDA: Find Houstonia caerulea in USDA Plants
FNA: Find Houstonia caerulea in the Flora of North America (if available)
Google: Search Google for Houstonia caerulea

Metadata

Record Modified: 2012-10-03
Research By: TWC Staff

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