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perennial

Blue Cardinal Flower

Lobelia siphilitica

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Blue Cardinal Flower (Lobelia siphilitica) at Ashcombe Farm & Greenhouses

Lobelia siphilitica flowers

Lobelia siphilitica flowers

(Photo courtesy of NetPS Plant Finder)

Blue Cardinal Flower (Lobelia siphilitica) at Ashcombe Farm & Greenhouses

Lobelia siphilitica in bloom

Lobelia siphilitica in bloom

(Photo courtesy of NetPS Plant Finder)

Plant Height:  24 inches

Flower Height:  3 feet

Spacing:  16 inches

Sunlight:  partial shade 

Hardiness Zone:  4a

Description:

A wonderful form with true light blue flower spikes, excellent in the shade garden or containers; maintains a good form throughout the season and is excellent in a border planting

Ornamental Features

Blue Cardinal Flower features showy spikes of powder blue tubular flowers rising above the foliage from early to mid summer. The flowers are excellent for cutting. Its pointy leaves remain green in color throughout the season. The fruit is not ornamentally significant.

Landscape Attributes

Blue Cardinal Flower is an herbaceous perennial with an upright spreading habit of growth. Its medium texture blends into the garden, but can always be balanced by a couple of finer or coarser plants for an effective composition.

This is a relatively low maintenance plant, and is best cleaned up in early spring before it resumes active growth for the season. It is a good choice for attracting butterflies and hummingbirds to your yard. It has no significant negative characteristics.

Blue Cardinal Flower is recommended for the following landscape applications;

  • Mass Planting
  • General Garden Use

Planting & Growing

Blue Cardinal Flower will grow to be about 24 inches tall at maturity extending to 3 feet tall with the flowers, with a spread of 18 inches. When grown in masses or used as a bedding plant, individual plants should be spaced approximately 16 inches apart. It grows at a fast rate, and under ideal conditions can be expected to live for approximately 5 years.

This plant should be grown in a location that is shaded from the hot afternoon sun. It prefers to grow in moist to wet soil, and will even tolerate some standing water. It is not particular as to soil pH, but grows best in rich soils. It is somewhat tolerant of urban pollution. This species is native to parts of North America, and parts of it are known to be toxic to humans and animals, so care should be exercised in planting it around children and pets. It can be propagated by division.

 
 
Hardiness Zone Plant Height Minimum Sunlight
Characteristics
Massing  Garden 
Applications
Flowers  Attracts Wildlife 
Ornamental Features