Iris is a genus of 310 species and is in the plant family Iridaceae that also included gladiolus, crocus and freesia. The plants are all perennial and grow 2-79″ from rhizomes or bulbs forming clumps of leaves. The iris with rhizomes have 3-10 sword shaped leaves while the iris with bulbs have 2-10 narrow leaves. The flowers appear on a long erect stems that may be branched. The flowers consist of three outer sepals called falls that usually are spreading or droop downward, and three inner petals called standards, that are upright. The standards may be delicate or large and showy and the falls may have various attractive and distinctive markings including conspicuous veining, a patch of yellow or white known as a signal, or a row of hairs known as a beard. Petals and sepals may be lavender, blue, purple, white, pink, red, yellow, brown and combinations of these.
Iris can grow in a variety of soil types from dry to wet and some grow in shallow water. Bulbus iris prefer drier soil than rhizomatous iris and both grow well in full sun to partial shade. The bloom time various greatly and with careful planning it is possible to have some species of iris blooming from early spring to mid summer.
The genus name, Iris, honors the Greek goddess Iris whose name, ἶρις (îris) means rainbow and may refer to the wide variety of flower colors that resemble a rainbow.
Photo Credit: Team New Orleans, US Corps of Army Engineers, Wikimedia Commons
The environmental conditions of the Southeast have given rise at least seven species of native iris there but they may be native to other regions also. The iris described here are native to at least three states in the Southeast.
Zigzag Iris ( Iris brevicaulis)
Native to Missouri, Illinois, Indiana, Ohio and Kansas as well as places in the Southeast and Southwest, zigzag iris is also known as short-stemmed iris, Lamance iris, or leafy blue flag. It grows in swamps, shaded damp woods, and bottom lands and is a good choice for use along waterways and for rock and woodland gardens.
Height: 10-12″
Bloom Time: Mid spring
Bloom Color: Blue-purple to pale blue-violet, lavender, white, with yellow signals
Light: Full sun to part shade
Soil: Average, medium moist to wet, well-drained, slightly acidic
USDA Hardiness Zones: 4-8
Photo Credit: Eric Hunt, Wikimedia Commons
Crested iris (Iris cristata)
Also known as lady’s calamus, crested iris is native to Mississippi, Alabama, Georgia, South Carolina, North Carolina, Virginia, West Virginia, Tennessee, and Kentucky as well as places in the Southwest, Midwest, Mid Atlantic, and New England. It grows on rocky hillsides, in ravines, on mountain ledges, and along streams. Flowers are fragrant. Crested iris can be used as a groundcover and is useful in shade, rock and fragrance gardens.
Height: 4-9″
Bloom Time: April-May
Bloom Color: Blue, pale blue, lavender, purple, lilac, and rarely white or pink
Light: Part shade but tolerates full sun
Soil: Average to fertile, high to medium moist, well-drained
USDA Hardiness Zones: 3-9
Photo Credit: Eric Hunt, Wikimedia Commons
Copper Iris (Iris fulva)
Known for its unusual color and drooping standards, copper iris is native to Arkansas, Louisiana, Mississippi, Alabama, Georgia, South Carolina, North Carolina, Virginia, West Virginia, Tennessee and Kentucky as well as places in the Southwest, and Midwest. It is found in flooded areas and wet places such as marshes, stream banks, swamps, and wet pastures, normally in water up to 6 inches. The flowers attract hummingbirds. Good choice for bird, pollinator, wildlife, water, bog, and rain gardens.
Height: 18-31″
Bloom Time: April to June
Bloom Color: Copper-colored to deep red, occasionally yellow
Light: Full sun
Soil: Fertile, organically rich, moist to wet, acidic
USDA Hardiness Zones: 3-10
Photo Credit: James Henderson, Wikimedia Commons
Giant Blue Iris (Iris giganticaerulea)
Also known as giant blue flag, giant blue iris is native to Alabama, Louisiana, and Mississippi as well as areas in the Southwest. Tolerant of brackish water, it grows in shallow freshwater, clearings within swamps, wet meadows and marshes.
Height: 28-71″
Bloom Time: Early to mid spring
Bloom Color: Shades of blue, lavender and violet, rarely white.
Light: Full sun to partial shade
Soil: Fertile, organically rich, moist to wet, acidic
USDA Hardiness Zones: 7-11
Photo Credit: Irvin Louque, Wikimedia Commons
Dixie Iris (Iris hexagona)
Also known as Carolina iris, and prairie iris, this rare native species is endemic to South Carolina, Georgia and Florida where it grows in wet meadows, wet marshes, bogs, coastal plains, swamps, bayous, dam hillsides, ditches, and riversides as well as streams of coastal areas. It is a good choice for water and bog gardens.
Height: 3-4′
Bloom Time: Spring
Bloom Color: Blue, violet, with yellow signals
Light: Full sun, tolerates partial shade
Soil: Humusy consistently moist to wet, acidic
USDA Hardiness Zones: 7-9
Photo Credit: Wikipedia
Slender Blue Flag (Iris prismatica)
Native to Virginia, West Virginia, North Carolina, South Carolina, Tennessee, Georgia, and Alabama, slender blue flag grows in bogs and marshes and along streams. It tolerates salty conditions, summer drought, occasional flooding and deer, but attracts birds including hummingbirds. Also known as cubeseed iris, it is a good choice for use along streams and ponds as well as in seaside, bog, bird, and wildlife gardens.
Height: 1-3′
Bloom Time: Late spring to mid summer
Bloom Color: Pale blue to blue violet with white blotch
Light: Full sun to part shade
Soil: Average, moist to wet, neutral to slightly acidic
USDA Hardiness Zones: 3-9
Photo Credit: Masebrock, Wikimedia Commons
Prairie Iris (Iris savannarum)
Growing in open freshwater swamps, prairie iris is native to Alabama, Georgia and Florida. It dominates all other iris species in Florida.
Height: 3-4′
Bloom Time: March to April
Bloom Color: Violet-blue to blue to white.
Light: Full sun to part shade
Soil: Rich loamy sandy to poor sandy loam soils, dry to wet, acidic
USDA Hardiness Zones: 8-9
Photo Credit: New York Botanical Garden, Wikimedia Commons
Savannah Iris (Iris tridentata)
Native to Tennessee, North Carolina, South Carolina, Georgia, Alabama, and northern Florida, savannah iris can be found in wetlands such as swamps, bogs, and wet meadows. The flowers are fragrant and attract hummingbirds and butterflies.
Height: 12-18″
Bloom Time: May-June
Bloom Color: Blue-purple
Light: Partial to light shade
Soil: Occasionally wet, acidic
USDA Hardiness Zones: 7-10
Photo Credit: David Anstiss
Dwarf Violet Iris (Iris verna)
Also known as dwarf iris and vernal iris, this iris is native to Virginia, West Virginia, Kentucky, Tennessee, North Carolina, South Carolina, Georgia, Alabama, Mississippi, and Florida as well as to places in the Midwest and Mid Atlantic. It grows in nutrient-poor acidic soils in open to semi-shaded woodlands. With its intensely fragrant flowers that appear before the foliage, it is a good choice for rock, shade, woodland, and fragrance gardens.
Height: 2-3″
Bloom Time: Spring
Bloom Color: Light to deep blue or violet, rarely white; falls with yellow signals
Light: Partial sun but tolerates full sun
Soil: Average, dry to moist, well-drained, neutral to acid
USDA Hardiness Zones: 5-9
Photo Credit: Eric Hunt, Wikimedia Commons
Blue Flag Iris (Iris versicolor )
Native to Virginia and West Virginia as well as to places in the Rocky Mountain area, New England, Mid Atlantic, and Midwest, blue flag iris grows in sedge meadows, marshes, and along stream banks and shores. Also known as harlequin blue flag, larger blue flag, northern blue flag, and poison flag, it tolerates occasional flooding and can be grown in 4″ of water.
Height: 2-3′
Bloom Time: May to June
Bloom Color: Light to deep blue and purple
Light: Full; tolerates partial shade
Soil: Average, moist to wet,
USDA Hardiness Zones: 3-6
Photo Credit: D. Gordon E. Robertson, Wikimedia Commons
Virginia Iris (Iris virginica )
Also known as southern blue flag, Virginia iris is native to Virginia, West Virginia, North Carolina, South Carolina, Georgia, Alabama, Mississippi, Louisiana, Arkansas, Kentucky, Tennessee, and Florida as well as to places in the Southwest, Midwest, and Mid-Atlantic. It grows in wet areas, such as marshes, wet meadows, swamps, and river bottoms, and is an excellent choice for a pond margin, water garden or rain garden.
Height: 2-3′
Bloom Time: May to July
Bloom Color: Light blue to deep violet, rarely white
Light: Full sun
Soil: Humusy to sandy, moist to very wet, acidic
USDA Hardiness Zones: 5-9
Photo Credit: Eric Hunt, Wikimedia Commons
The southeast includes the following states: Virginia, West Virginia, North Carolina, South Carolina, Georgia, Alabama, Mississippi, Louisiana, Arkansas, Kentucky, Tennessee, and Florida. Most of these states are characterized by hot, humid summers and cool to mild winters, with Florida’s tip being tropical. Summers are generally hot and humid throughout the entire region with maximum summer temperatures over 90 F in Louisiana, Florida, Mississippi, Arkansas, and Georgia. Minimum winter temperatures are below 32 F in Kentucky, Tennessee, Virginia and West Virginia, but Florida boasts a minimum winter temperature of 51.4 F. Arkansas has the most days (123) with less than 30% cloud cover, while West Virginia has the least (60). Precipitation is abundant in the area and comes mostly in the form of rain. Louisiana has the most annual precipitation with 60.1″, while Virginia has the least with 44.3″.