How to Grow and Care for Flax Flowers

Harvest These Easy and Quick to Grow Flowers For Their Seeds

Flax flowers with light blue petals closeup

The Spruce / Evgeniya Vlasova

The flax flower (Linum usitatissimum) is a pretty, fast, and easy-growing annual. Once mature, it produces an abundance of short-lived but attractive and delicate blue flowers that are frequently replaced over the summer. It's usually densely sown and works well in a meadow, wild or cottage garden setting, often reaching up to 3 feet in height.

The blooms on these flowers 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 they start to rattle—usually a couple of months after flowering.

Botanical Name Linum usitatissimum
Common Name Flax, common flax, linseed oil plant
Family Linaceae
Plant Type Annual, herb
Mature Size Up to 3 ft. tall
Sun Exposure Full
Soil Type Sandy, loamy
Soil pH Acidic, neutral, alkaline
Bloom Time Summer
Flower Color Blue
Hardiness Zones 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
Native Area Asia, Europe
Toxicity Toxic to pets

Flax Flower Care

With the right cool conditions, flax flowers will proliferate in abundance. Select a sunny and sheltered position, and they should thrive.

Flax flowers on stems with buds and light blue petals

The Spruce / Evgeniya Vlasova

Flax flowers with blue petals clustered together closeup

The Spruce / Evgeniya Vlasova

Flax flower with blue petals and buds growing closeup
Flax flowers with blue petals in shrubs by blowing tall grass

The Spruce / Evgeniya Vlasova

Light

Although flax flowers don't appreciate excessively hot weather, they do thrive in a sheltered, full-sun position.

Soil

Flax flowers don't cope well in dense, wet clay soils. Their preference is for a light, sandy, loamy soil type, and it needs to be well-drained.

If the soil quality is poor, ideally it'll be well prepared with compost or other organic matter. Although flax flowers are known for being greedy, getting the balance right is important. Overly nutrient-rich soils can also create problems with excessively leggy growth.

Water

Flax flowers appreciate evenly moist soil, particularly when establishing, but care should be taken to ensure it doesn't become saturated as root rot can be a problem.

Once established, flax flowers won't need too much watering unless you live in a hot and dry region. Here, you could 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

Fertilizer isn't needed for flax flowers unless the soil they're planted in is of inferior quality. In this case, a diluted application every fortnight on the run-up to the seed capsules forming could be beneficial.

Pruning

Ensuring that the area surrounding establishing flax flowers is weed-free is crucial. Young plants can quickly be choked out. Be careful not to damage the flax roots when pulling any weeds out.

After they're established, the flax plant 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 don't appreciate root disturbance. For this reason, division isn't normally encouraged.

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.

Overwintering

Flax is hardy enough to withstand mild frosts. During the winter, a good layer of mulch would be welcome.

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.

Common Problems with Flax Flowers

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.

FAQ
  • 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.

  • Can I use other parts of the flax flower?

    The tall and thin stems also contain a soft fiber that can be harvested to make cloth linen. Harvesting the fibers isn't normally something done by home gardeners, though, as the process is complicated and requires a particularly wet climate.

  • Can flax flowers grow indoors?

    While this is possible, keep in mind that the flowers last for a very short period of time, and it's difficult to grow enough flax flowers in containers to provide enough seeds for nutritional use.