Common Name: great blue cardinal flower
Type: Herbaceous perennial
Family: Campanulaceae
Zone: 4 to 9
Height: 1.00 to 1.50 feet
Spread: 0.75 to 1.00 feet
Bloom Time: July to September
Bloom Description: Lilac
Sun: Full sun to part shade
Water: Medium to wet
Maintenance: Low
Suggested Use: Naturalize, Rain Garden
Flower: Showy
Tolerate: Deer, Heavy Shade, Wet Soil
Culture
Easily grown in rich, humusy, medium to wet soils in full sun to part shade. Needs constant moisture. Will tolerate full sun in cool, northern climates, but otherwise appreciates part shade. Divide clumps in spring as needed. May self-seed in optimum growing conditions, forming attractive colonies.
‘Lilac Candles’ is similarly well-suited to moist soil conditions, but does surprisingly well in average garden soils as long as those soils are not permitted to dry out. Divide clumps in spring. ‘Lilac Candles’ does not produce viable seed.
Noteworthy Characteristics
Lobelia siphilitica, commonly called great lobelia or blue cardinal flower, is a Missouri native perennial which typically grows in moist to wet locations along streams, sloughs, springs, swamps, meadows and in low wooded areas. A clump-forming perennial which features light to dark blue, tubular, 2-lipped flowers with the three lobes of the lower lip appearing more prominent than the two lobes of the upper lip. Flowers arise from the upper leaf axils forming a dense terminal raceme atop stiff, unbranched, leafy stalks typically rising 2-3' tall. Finely-toothed, lance-shaped, light green leaves (to 5" long). Late summer bloom period.
Genus name honors Matthias de l'Obel (1538-1616), French physician and botanist, who with Pierre Pena wrote Stirpium Adversaria Nova (1570) which detailed a new plant classification system based upon leaves.
Species name of siphilitica arose from a prior medicinal use of the plant in the treatment of venereal disease.
‘Lilac Candles’ is noted for its dwarf size (growing to only 18” tall), strong flowering stems and numerous lilac flowers. U.S. Plant Patent PP15,236 issued October 19, 2004.
Problems
No known serious insect or disease problems. Snails and slugs may damage the foliage.
Uses
Provides late summer bloom to the perennial border, wild garden, native plant garden, woodland garden or naturalized planting. Also effective near ponds or streams.