Perennial Flax is, as the common name says, a flowering, short-lived, perennial subshrub in the flax family, native to Asia and Europe, with attractive blue flowers that bloom from spring into summer. It is a heavy bloomer with flowers that open early on sunny mornings, but often drop petals by the end of the day. The thin, wiry stems that support the flower buds appear delicate, but are difficult to break. The genus name comes from the Latin name of the plant and the species name means perennial. Perennial Flax grows best in full sun or partial shade and well-drained soil is essential. A light soil and full sun will, however, encourage growth and flowering. It will tolerate drought and dry or rocky soil, but clay soils can cause the plant to root shallowly that will cause problems for the plant in cold weather. If clay cannot be avoided, consider growing the plant as an annual. After perennial flax finishes flowering in summer, prune back the stems by half to prevent the plants from becoming leggy and sparse. Pruning halfway through the bloom season will extend flowering. Division is not advisable, because the roots system is sparse, but you can propagate with seed or stem cuttings in summer. Diseases, Insect Pests, and Other Plant Problems: Cutworms and grasshoppers can be occasional pests.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; Loam (Silt); Shallow Rocky
Soil pH
Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage | Occasionally Dry
Available space
12 inches-3 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 1 ft. 0 in. - 2 ft. 0 in. | Width: 0 ft. 9 in. - 1 ft. 6 in.
Growth rate
Medium
Maintenance
Medium
Canopy layer
4 - Herbaceous (1-3 ft)
Form & Appearance
Habit / form
Creeping; Erect; Multi-stemmed
Foliage
Semi-evergreen
Leaf color
Blue; Green
Leaf type
Simple
Leaf arrangement
Whorled
Leaf shape
Linear
Leaf margin
Entire
Leaf feel
Smooth
Leaf size
1-3 inches long, < 1 inch wide
Hairs present
No
Leaf detail
Short, narrow, linear leaves in dense pseudo-whorls. The leaves are are up to 1½ inches long and less than ¼ inch across, linear-oblong, gray-green or gray-blue, smooth along their margins, and hairless.
Flower color
Blue; White
Flower value
Showy
Flower form
Cyme
Flower shape
Wheel
Flower size
< 1 inch
Flower detail
Each stem terminates in a cyme of about 10 flowers that droops downward when the flowers are in bud. When a flower blooms, it becomes more erect. Individual flowers are about 1 inch across, consisting of 5 light to medium blue petals, 5 dull green sepals, 5 stamens with white anthers, and 5 slender styles. The petals have dark blue veins that radiate from the center of the flower.
Bloom time
Spring; Summer
Fruit color
Brown/Copper
Fruit type
Capsule
Fruit detail
Globoid seed capsule containing 10 cells (5 fertile cells and 5 sterile cells) and 10 flattened seeds.
Stem color
Blue; Gray/Silver; Green
Stem detail
One or more unbranched stems rise up from the base of the plant. These flowering stems may be erect, or they can sprawl across the ground.
Wildlife & Ecology
Native status
Non-native
Origin
Europe and Asia
Distribution
Naturalized throughout western and central North America