Lewis Flax (Lewisii)

The Lewis Flax (Lewisii) is generally described as a perennial subshrub or forb/herb. This is native to the U.S. (United States) has its most active growth period in the spring . The Lewis Flax (Lewisii) has green foliage and inconspicuous blue flowers, with a moderate amount of conspicuous brown fruits or seeds. The greatest bloom is usually observed in the indeterminate, with fruit and seed production starting in the spring and continuing until summer. Leaves are not retained year to year. The Lewis Flax (Lewisii) has a moderate life span relative to most other plant species and a moderate growth rate. At maturity, the typical Lewis Flax (Lewisii) will reach up to 2.5 feet high, with a maximum height at 20 years of 0 inches.

The Lewis Flax (Lewisii) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by seed. It has a slow ability to spread through seed production and the seedlings have high vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -36°F. has medium tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Ethnobotanic: Cultivated flax (Linum usitatissimum) is grown both for fiber (flax) and seed oil (linseed). Linseed oil may cause skin irritation upon contact.

Ingestion causes difficulty of breathing, paralysis, and convulsions (Russell et al. 1997).

Grazing/rangeland: Blue and Lewis flax are noted to have fair forage value for livestock and wildlife during spring and winter. Plants stay green throughout the growing season providing some forage value. Birds use the seed and capsules in fall and winter. All species provide diversity to the seeded plant community.

Erosion control/reclamation/greenstripping: All flax species are noted for their value in mixes for erosion control and beautification values. The six week flowering period and showy blue flowers make seedings more aesthetically pleasing and increase plant biodiversity. Due to the semi-evergreen nature of the species, flax can also be used as a fire suppressant species in greenstrip plantings.

Wildlife: Flax is considered desirable forage for deer, antelope, and birds, either as herbage or seed. They may also provide some cover for selected small bird species.

General Characteristics

General: Flax Family (Linaceae). Linum perenne is introduced from Eurasia. Linum lewisii is a comparable U.S. native plant (figure 1). In general, flax is an annual or short-lived, semi-evergreen perennial forb, sometimes semi-woody at base with attractive flowers ranging from white to blue to yellow to red in color. Common in the western United States, blue flax is considered a woody subshrub in the PLANTS database (USDA, NRCS 2000). According to Cronquist et al. (1997), “the only significant difference between Linum lewisii and the Eurasian Linum perenne appears to be that the former is homostylic, and the latter heterostylic.”

Flax plants have many narrow, small, alternate (rarely opposite), simple and entire leaves that are sessile (lacking stalks) on the stems. The perfect and regular, generally showy flowers are borne in racemes or cymes. The sepals, petals, and stamens are five, the fruit a capsule, and the seeds in most species are mucilaginous when wet.

Required Growing Conditions

Lewis flax can be found from Alaska to California and east to Minnesota in mixed grass, sagebrush, shadscale, piñon-juniper, mountain brush and aspen communities and in openings in coniferous forests. Blue flax is native to Eurasia and has been planted successfully throughout the United States. For current distribution, consult the Plant Profile page for this species on the PLANTS Web site.

Adaptation Flax species do best on well-drained soils. Most ecotypes do well on infertile, disturbed soils. They have excellent cold winter and drought tolerance. They will tolerate weakly saline to weakly acidic sites. Plants are usually found in open areas, but will tolerate semi-shaded conditions. They are fire resistant due to leaves and stems staying green with relatively high moisture content during most of the fire season.

Cultivation and Care

Planting: Flax should be seeded with a drill or broadcast at a depth of 1/4 inch or less into a firm seedbed. The ideal seeding depth is 1/8 inch. Flax is not recommended for single species seedings. The full seeding rate (not recommended) for these forbs is 4 pounds Pure Live Seed (PLS) per acre or 24 PLS per square foot. When used as a component of a mix, adjust to percent of mix desired. For mined lands and other harsh critical areas, doubling the seeding rate component of flax is not required.

The best seeding results are obtained from seeding in late fall to very early spring (because of grass component of mix) on heavy to medium textured soils and in late fall on medium to light textured soils. Late summer (August - mid September) seeding is not recommended. Dormant fall seedings (preferred seeding period for flax) will pre-chill seed and reduce seed dormancy which may be present. Mulching, irrigation, and weed control all benefit stand establishment. Seedling vigor is good, but not as good as most grasses. Germination normally occurs the first growing season, but may not occur until the second growing season. Full flowering should not be expected until at least the second growing season.

Stands may require weed control measures during establishment. Because flax is a broadleaf plant, use of 2,4-D is not recommended. Mow weeds at or prior to their bloom stage. Grasshoppers and other insects may also damage new stands and pesticides may be needed.

General Upkeep and Control

Growth of flax begins in early spring and flowers appear in mid May through early July depending on species. Weed control and removal of very competitive species may improve chance of establishment. Damage from wildlife and rodents may occur and they may need to be controlled. Disease problems are minimal with flax; however fungus problems have been noted for some native species.

Environmental Concerns: Flax species establish relatively quickly and easily via seed under favorable climatic conditions. They are not rhizomatous or considered weedy or invasive species but could spread into adjoining vegetative communities under ideal climatic and environmental conditions. They coexist with other species and add biodiversity to those plant communities. ‘Appar’ blue flax seed normally germinates the first growing season following planting under favorable temperatures if moisture is available and it generally does not maintain a viable seed-bank. Native flax accessions tested maintain a portion of seed, which does not germinate the first growing season, as a viable seed-bank.

Seed Production Flax should be seeded in 24 inch rows at the rate of 2.5 pounds PLS per acre or 36 inch rows at the rate of 1.5 pounds PLS per acre (25 to 30 seeds per linear foot of row) to allow mechanical weed control. It should be seeded in early spring (April - May).

Hand rouging within row and cultivation between rows may be required. Split applications of nitrogen in spring and fall and application of phosphorus in fall will enhance production. For optimum production, do not stress plants for moisture during late bud stage, pollination and re-growth.

Seed is generally harvested in late July to mid-August by wind-rowing before seed shatter and combining with pickup attachment once green stems have dried. Seed is mature when capsules are dry and seed is hard and dark in color. Flowering is indeterminate with mature capsules and the possibility of some flowers present at harvest period. Some seed will shatter once capsules open. Seed should be allowed to dry to 12 (bins) to 15 (sacks) percent moisture and then stored in a cool dry area. Seed retains viability for several years under these conditions.

Seed yields of 600 to 700 pounds per acre of blue flax can be expected under irrigated conditions and 200 to 300 pounds per acre under dryland conditions.

Seed yields of Lewis flax from irrigated fields average 300 to 350 pounds per acre. Seed production of Lewis flax under dryland conditions is not recommended below 16 inches of average annual rainfall.

Plant Basics
Growth Rate Moderate
General Type Subshrub, Forb/herb
Growth Period Spring
Growth Duration Perennial
Lifespan Moderate
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Indeterminate
Displays Fall Colors No
Shape/Growth Form Bunch
Drought Tolerance Medium
Shade Tolerance Intolerant
Height When Mature 2.5
Vegetative Spread None
Flower Color Blue
Flower Conspicuousness Yes
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Spring Summer
Seed Spread Rate Slow
Gardening Characteristics
Propagations (Ways to Grow) Seed
Moisture Requirements Medium
Cold Stratification Required No
Minimum Temperature -36
Soil Depth for Roots 14
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Regrowth Rate Slow
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 5.6–8.4 pH
Precipitation Range 10–10 inches/yr
Planting Density 0–0 indiv./acre
Soil Textures Coarse, Medium
Soil Depth for Roots 14
Minimum Frost-Free Days 95 day(s)
Salinity Tolerance Low
CaCO3 Tolerance High
Sustainability & Use
Leaf Retention No
Palatability Low
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database, plants.usda.gov.
National Plant Data Center, Baton Rouge, LA 70874-4490 USA