Flax (Linum usitatissimum) is a pretty, fast-growing annual in the garden that is also grown for commercial harvest. Once mature, the slender erect plant produces an abundance of attractive, short-lived delicate blue flowers over narrow grey-green leaves. It's usually densely sown in spring and works well in a meadow, wild, or cottage garden setting, often reaching up to three feet in height.
The blooms only last for around a day and the capsules they form contain up to ten little dark seeds. The seeds can be harvested once the capsules turn brown and start to rattle—usually a couple of months after flowering. Flax is toxic to pets.
|Common Name||Flax, common flax, linseed oil plant|
|Botanical Name||Linum usitatissimum|
|Plant Type||Annual, herb|
|Mature Size||2-3 ft. tall, 1 ft. wide|
|Soil Type||Sandy, loamy|
|Soil pH||Acidic, neutral, alkaline|
|Hardiness Zones||3-8 USDA|
|Native Area||Asia, Europe|
|Toxicity||Toxic to pets|
Flax Flower Care
In the right cool conditions, flax flowers will proliferate in abundance. Select a sunny and sheltered position with well-draining soil, and they should thrive.
Although flax flowers don't appreciate excessively hot weather, they do thrive in a sheltered, full-sun position.
If the soil quality is poor, amend it with compost or other organic matter. Although flax flowers aren't known for being greedy, getting the balance right is important. Overly nutrient-rich soils can also create problems with excessively leggy growth.
Flax flowers appreciate evenly moist soil, particularly as they establish, but care should be taken to ensure it doesn't become saturated as too much water can cause root rot.
Once established, flax flowers won't need too much watering unless you live in a hot and dry region. Use a thin layer of mulch to help retain moisture, and it can also help with weed control.
Temperature and Humidity
Flax flowers aren't suited to overly hot and dry regions, where they can suffer from woody and short growth. They thrive in damp, cool climates.
Fertilizer isn't needed for flax flowers unless the soil is of inferior quality. In this case, a diluted application of a water-soluble fertilizer every two weeks before the seed capsules form could be beneficial.
Types of Flax
There are other attractive annual and perennial flax varieties:
- Linum grandiflorum (flowering flax, red flax, scarlet flax, or crimson flax) is a hardy annual native to northern Africa and southern Europe featuring bright red blooms.
- Linum flavum (golden flax or yellow flax) is a perennial with bright yellow flowers native to central and southern Europe.
- Linum lewisii (prairie flax, wild blue flax) is a herbaceous perennial native to North America.
- Linum narbonense (Spanish blue flax) is a perennial with large blue flowers streaked with dark blue that is native to the Mediterranean area.
- Linum perenne subsp. alpinum (Alpine flax) is a compact perennial with blue flowers native to Europe.
The planting area around flax flowers must be weed-free. Young plants can quickly be choked out. As you weed, be careful not to damage the flax roots when pulling weeds. Once they're established, the flax plants should be able to compete with any stray weeds.
Some gardeners cut their flax down halfway after their initial bloom. However, if you live in a hot and dry region, this can impact the chance of reflowering during the bloom season.
Propagating Flax Flowers
Flax flowers have weak root systems and don't appreciate root disturbance. Annual flaxes with their single growing season should not be propagated through division or from cuttings. Therefore, they should be propagated from seed.
How to Grow Flax Flowers From Seed
With the right conditions, flax flowers grow easily from seed. They can be sown directly into their outdoor position in spring, provided there are no expected hard frosts. Outdoor sowing is usually recommended, as seedlings don't take kindly to being transplanted.
If you have the time and inclination, you could consider succession sowing as this will give you a longer flowering season. Seedlings appreciate consistent moisture, but overly wet and humid conditions can cause damping-off fungus, particularly when germinating in poorly ventilated indoor positions.
Potting and Repotting Flax Flowers
When growing flax flowers in a container, the depth of the pot matters more than the diameter. Start with a depth of no less than 10 inches. Fill the pot with well-draining, sandy, loamy soil, and ensure there are adequate drainage holes in the bottom to prevent the roots from sitting in water. Keep the soil moist, but not wet.
Flax is an annual so it will die at the end of the growing season, even in a warm climate. But it easily reseeds itself the next year and every year thereafter if you let it. Mark the location to avoid removing the volunteer seedlings in the spring.
Common Pests and Plant Diseases
Although fast and easy growing, flax flowers can be susceptible to a variety of pests and fungal issues. Rust, powdery mildew, and fusarium wilt are potential problems. Rhizoctonia root rot can also develop, particularly if the flax is planted in hot and humid regions. Aphids can be a problem, too, but often they can be dislodged by using a steady stream of water or by using insecticidal soap.
There is a moth larva that specifically eats flax flowers and their seeds. It's known as the flax bollworm and can be a particular problem in northwestern parts of the United States. The larvae are small, green, and look similar to inchworms, with identifiable white stripes along the upper parts of their body.
How to Get Flax Flowers to Bloom
If flax does not bloom, it is most likely due to insufficient sunlight. If you are growing it in a container, move it to a location in full sun and see if that does the trick.
How can I use my flax flower seeds?
Common flax is widely cultivated on a commercial scale for its nutrient-packed seeds and its fiber. If grown in large enough quantities, these seeds can be collected for eating or producing linseed oil. They're high in protein and packed with the essential fatty acid omega-3. You can also collect the seeds to share, sow again next spring in the same location, or establish a new site.
Can I use other parts of the flax flower?
Can flax flowers grow indoors?
While this is possible, keep in mind that the flowers last for a very short period and it's difficult to grow enough flax flowers in containers outdoors. Houseplant flax will not produce enough seeds for nutritional use.