Lobelia siphilitica
A tall North American native perennial with blue tubular flowers on long spikes that bloom from late summer to autumn and thrive in moist to wet soils, attracting hummingbirds and bees.
Common Names
Great Blue Lobelia, Blue Cardinal Flower, Blue Lobelia, Great Lobelia, Tall Blue Lobelia, Virginia Bellflower, Vomit Root
Summary
Lobelia siphilitica, commonly called Great Blue Lobelia or Blue Cardinal Flower, is a North American native perennial in the Campanulaceae that grows about 2–4 feet tall with lance-shaped leaves and spikes of blue two-lipped flowers from midsummer to autumn. It thrives in moist to wet soils in sun to partial shade, and occurs in wetlands, swamps, stream banks, meadows, and damp woodlands; nectar attracts bees, hummingbirds, and butterflies, and it can form colonies through self-seeding.
Propagation is by seed or division; seeds germinate with light and can be sown on the soil surface, and plants may self-seed to maintain colonies. All parts are poisonous if ingested, and historical lore links the name siphilitica to syphilis due to traditional medicinal use. It is a versatile addition to borders, rain gardens, wetlands, or near ponds and streams in moisture-loving plantings. Sources.
Lifecycle
Perennial
Height
2-3 feet
Spread
12-18 inches
Hardiness Zones
Zones 4-9
Sunlight Requirements
Ideally Full Sun; also tolerates Partial Shade and Full Shade.
Soil Type
Moist, humus-rich soil that stays wet, tolerating sandy loam, gravelly, or clay soils
Soil Drainage
Moist but well-drained soil.
Soil pH
No specific ideal pH; tolerates all soil pH levels (acid, alkaline, and neutral)
Bloom Color
Blue
Bloom Time
Summer and Fall
Foliage Color
Green
Fall Foliage Color
Green
Leaf Lifecycle
Deciduous
Growth Rate
Medium rate.
Seasons of Interest
Summer and Fall
Propagation Methods
Seeds, Division
Attracts Wildlife
Bees, Hummingbirds, Butterflies, Other pollinators, Birds
Taxonomy
- Taxonomic Rank
- Species
- Author
- L.
- Publication
- Sp. Pl. 2: 931. 1753 [1 May 1753]
Superior Taxa
- Kingdom
- Plantae
- Subkingdom
- Pteridobiotina
- Phylum
- Angiosperms
- Order
- Asterales
- Family
- Campanulaceae
- Genus
- Lobelia
Synonyms
Lobelia antisyphilitica Lobelia densiflora Lobelia coelestis Lobelia bollii Lobelia reflexa Rapuntium siphiliticum Rapuntium syphiliticum Lobelia siphilitica var. ludoviciana Lobelia siphilitica var. maculata Lobelia siphilitica f. laevicalyx Lobelia siphilitica var. candida Lobelia siphilitica f. albiflora Lobelia siphilitica var. minor Lobelia siphilitica var. alba Lobelia belgica Lobelia siphilitica var. densiflora Lobelia siphilitica f. alba Lobelia siphilitica var. rosea Lobelia siphilitica var. grandis Dortmanna siphilitica Lobelia siphilitica f. siphilitica Lobelia siphilitica var. siphilitica Lobelia siphilitica var. bollii Lobelia siphilitica f. ludoviciana Lobelia siphilitica f. purpurea