Linum perenne (Perennial Flax)

Plant Info
Also known as: Blue Flax, Garden Flax
Genus:Linum
Family:Linaceae (Flax)
Life cycle:perennial
Origin:Europe, Asia
Habitat:part shade, sun; disturbed soil; roadsides, gardens
Bloom season:May - July
Plant height:1 to 3 feet
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: 5-petals Cluster type: panicle Cluster type: raceme

[photo of flowers] Drooping panicle or multiple racemes of stalked flowers at branch tips. Flowers are up to ~1¾ inches diameter with 5 broad petals each 10 to 25 mm long, bright blue to blue-violet, usually white or yellowish at the base. In the center are 5 white-tipped stamens surrounding 5 styles, each style with an enlarged, round to elliptic tip. Within a population, some plants have short stamens with longer styles, some short styles with longer stamens.

[photo of sepals] The 5 sepals are elliptic to egg-shaped, usually blunt at the tip, hairless, and green with a papery translucent edging. Flower stalks are slender and smooth, drooping in bud, becoming erect at flowering and may droop again in fruit. Flowers open in early morning, the petals falling away by noon.

Leaves and stems: Leaf attachment: alternate Leaf type: simple

[photo of leaves] Leaves are erect to ascending, alternate but may appear whorled on the lower stem, up to about 1 inch (1 to 3 cm) long, less than ¼ inch wide, lance-linear, pointed or blunt at the tip, 1-nerved, stalkless, toothless and hairless, becoming smaller as they ascend the stem.

[photo of clustered stems] Stems are multiple from the base, erect to ascending, branching near the base or just towards the top, leafy, round in cross section, hairless and smooth.

Fruit: Fruit type: capsule/pod

[photo of developing fruit] Fruit is a round capsule about 1/3 inch (5 to 9 mm) long, straw-colored at maturity, the sepals persistent but withering. The capsule splits from the tip into 10 wedge shaped sections, each with 1 or 2 seeds.

Notes:

Perennial (or Garden) Flax, native to Europe and Asia, is sold in the garden trade, is commonly included in bird or wildflower seed mixes, and occasionally escapes cultivation. Two other blue flaxes can also be found here in Minnesota. Common flax (Linum usitatissimum) is a Eurasian species that is cultivated for its fiber, edible seeds and oil. Escaped plants can come from any number of sources including mud from commercial grain trucks, and backyard bird feeders. It is an annual that typically is unbranched, sepals have a fringe of hairs around the edge (ciliate), and leaves are 3-nerved.

Perennial Flax is more similar to the native Blue Flax (L. lewisii), so much so that some references treat our native as a variety of it. The most consistent difference is that the styles of Perennial Flax flowers are what's known as heterostylic, with some plants in a population having short stamens with longer styles and others with short styles and longer stamens, where the native Blue Flax has styles all the same length (homostylic). Descriptions of some other characteristics are inconsistent across references so it's difficult to recommend any that are reliable in the field.

While Perennial Flax has been known to escape cultivation, its distribution in Minnesota is murky; of the handful of collections, at least some are possible hybrids. Having seen confirmed Perennial Flax in cultivation, I now have to question our own sightings of the native Flax and will pursue this further in the coming seasons.

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More photos

Photos by K. Chayka taken in Ramsey County.

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