Houstonia caerulea
An eastern North American native perennial that forms a low-growing mat with blue-to-white flowers and bright yellow centers, blooms in spring to mid-summer, tolerates partial shade and moist, well-drained soils, and attracts pollinators while helping control weeds and erosion.
Common Names
Quaker Ladies, Azure Bluet, Bluets, Innocence, Little Bluet, Common Bluets
Summary
Houstonia caerulea, commonly known as Azure Bluet, is a small creeping perennial native to eastern North America, it forms a low groundcover to under 6 inches tall, with a basal rosette of spatulate leaves and slender unbranched stems bearing one pale blue flower per stem, each flower has four petals with a bright yellow center, producing a delicate carpeting display in spring, it tolerates full sun to partial shade and prefers well-drained soils that are moist to dry-mesic with a slightly acidic to neutral pH, hardy in USDA zones 3–8, propagation is by seed or division, seeds can self-seed, and the plant can spread to form carpets, landscape uses include rock gardens, lawns, path edges, and woodland or cottage garden settings, it attracts bees and butterflies and is deer- and rabbit-resistant
Lifecycle
Perennial
Height
3-6 inches
Spread
12-24 inches
Hardiness Zones
Zones 3-8
Sunlight Requirements
Ideally Full Sun to Partial Shade.
Soil Type
Well-drained, moist soil with slightly acidic to neutral pH and high organic matter; suitable soil types include loam, silt, or sandy soils
Soil Drainage
Moist but well-drained soil
Soil pH
5.0-8.0, Slightly acidic to neutral, Tolerates acidic to neutral soils
Bloom Color
Blue (pale blue most common; white blooms also common; lavender, pink, red, and purple varieties exist)
Bloom Time
Spring to Summer
Foliage Color
Green
Leaf Lifecycle
Deciduous
Growth Rate
Fast
Seasons of Interest
Spring, Summer, Fall, and Winter
Propagation Methods
Seeds, Division
Attracts Wildlife
Attracts bees, butterflies, and other pollinators.
Taxonomy
- Taxonomic Rank
- Species
- Author
- L.
- Publication
- Sp. Pl. : 105 (1753)
Superior Taxa
- Kingdom
- Plantae
- Subkingdom
- Pteridobiotina
- Phylum
- Angiosperms
- Order
- Gentianales
- Family
- Rubiaceae
- Genus
- Houstonia
Synonyms
Houstonia faxonorum Houstonia linnaei Houstonia linnaei var. elatior Houstonia pusilla Houstonia serpyllifolia Anotis coerulea Anotis gentianoides Oldenlandia caerulea Poiretia erecta Hedyotis caerulea f. albiflora Houstonia caerulea var. elatior Houstonia caerulea var. piersii Houstonia caerulea var. toxonorum Houstonia caerulea f. albiflora Hedyotis brachiata Hedyotis caerulea Hedyotis caerulea f. benkei Hedyotis gentianoides Houstonia caerulea var. caerulea Houstonia grandiflora Hedyotis caerulea var. faxonorum Houstonia caerulea var. faxonorum Houstonia caerulea f. caerulea