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Lobelia (low-BEE-lee-uh)

Common Name:  Cardinal flower, lobelia

Light:  - Part sun to part shade

Soil:  Loamy to rich, slightly acidic, evenly moist

Moisture:  Consistently moist to almost wet

Blooms:  Summer

Zones:  varies considerably by type

Lobelia cardinalis

Lobelia 'Monet Moment'

Lobelia Description and Cultural Information

Lobelia cardinalis, cardinal flower. 3 - 4'. These plants have a basal rosette of dark green foliage out of which grow thick, leafy stems forming a spike of scarlet, lipped flowers. The lower flowers will form seed pods while the upper flowers continue to grow and bloom. Plants self sow often. Zones 2 - 9.

Lobelia x hybrida, hybrid lobelia. 2 - 4'. Hybrid lobelias are derived from several species including L. cardinalis, L. siphilitica, L. fulgens, and L. splendens. Plants have a wide range of colors in pink, red, blue, purple, and shades in between. 'Queen Victoria' even has burgundy foliage with cardinal-red flowers, but unfortunately it is not particularly cold hardy (zone 7). 'Grape Knee Hi' is a sterile, long-blooming dwarf with deep purple flowers that is hardy to zone 6. 'Ruby Slippers' is a deep ruby red. 'Royal Fuchsia' is a fuchsia pink with dense, branching flower spikes. 'Cotton Candy' is a very light pink. 'Summit Snow' has dark green foliage and white flowers. Most hybrids will be hardy in zones 6 - 9 with proper culture, although 'Queen Victoria' and 'Grape Knee Hi' may be more tender.

Lobelia siphilitica, great blue lobelia. 2 - 3'. Great blue lobelia is very similar to cardinal flowers but the foliage is more rounded and the flowers, of course, are blue. Zones 4 - 8.

How to Grow:  Lobelias in the wild grow in ditches or near lakes and streams, basically anywhere there is very rich, wet soil. They will even thrive in heavy soil as long as they are kept wet. Plants will grow in full sun but prefer part sun to part shade. It is recommended to mulch plants in winter to prevent frost heave damage and help the soil around them retain moisture. Plants can sometimes be short lived, especially in dry soils, but they are easily propagated by stem cuttings and will also frequently self sow. To take cuttings, after they are finished blooming, cut the stems into pieces with 2 or 3 nodes and insert them in rich, moist soil. Stems will also root out in a glass of water. By replanting stems each year you can maintain a good colony in your garden, or let the seedlings spread around for a natural colony.

Landscape uses:  Plant lobelias in the moist garden with sweet flag grass (Acorus), Ligularia, Rodgersia, daylilies, moisture loving iris, spiderwort (Tradescantia), ferns, and astilbe.

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