Blue Flax: How to Plant, Grow, and Care For Linum Perenne
Thinking of adding some blue flax flowers to your garden? Blue Flax, also known as Linum Perenne, can be useful for a variety of different purposes. In this article, gardening expert Madison Moulton walks through every step you'll need to follow in order to successfully plant, grow, and care for blue flax.
When one thinks of flax plants, commercial flax fields typically come to mind. While its hold in the commercial world has somewhat died down, other plants in the flax genus have found their way into home gardens. With striking flowers and strong but delicate-looking stems, it’s easy to understand why they have become increasingly popular. The flowers only last a day, but the plants bloom throughout the flowering season.
Plants in the flax genus (Linum) offer slightly different characteristics that suit many gardeners’ needs. Most have blue flowers that are beautiful in color, with the most common ornamental type being Linum Perenne, commonly called Blue Flax or perennial flax. Other varieties sport violet, white, and even deep red flowers, allowing gardeners to explore different color options best suited to their style.
Part of this plant’s allure is its easy-going nature. Flax prefers plenty of light, but it can tolerate some shade. Other than that, it needs little water and the occasional pruning for aesthetic appeal. Its self-seeding nature allows it to return each year with its fleeting blooms.
Perennial flax suits seasoned green thumbs, laid-back gardeners, and newbies alike. Its small blooms add a touch of wildflower paradise whether planted in masses or small groups.
Blue Flax Plant Overview
Plant Type Perennial
Species Linum perenne
Native Area Europe
Hardiness Zone USDA 5-9
Exposure Full Sun
Maturity Date 2-5 years
Plant Spacing 12-18 inches
Height 1-2 feet
Watering Requirements Moderate
Pests Slugs, Snails, Aphids
Soil Type Well-draining
Plant With Drought Tolerant Plants
Don’t Plant With Moisture Needy Plants
Flax has a long recorded history, specifically in the textile industry. This European native has been used to make linen and rope for more than 30,000 years. It was first domesticated about 9,000 years ago in the Fertile Crescent region of the Middle East. 5,000 years ago, the use of this plant spread to Germany, Switzerland, and Asia.
Flax was extensively cultivated in ancient Egypt, where it was used to make linen for priests and to embalm mummies. As a symbol of purity in ancient culture, it was also commonly painted on temple walls. Trade of flax linen continued throughout the ages, eventually making its way to Rome. There, it was primarily used for Roman ship sails.
The later decline of the Roman empire also meant the decline of flax production. However, flax’s importance made a resurgence in the new millennium when the health of linseed oil came to light, along with the hygiene of flax linen.
Flax eventually made its way to North America through colonial trade routes. As a crop, flax flourished, until the rise of cotton in the early 20th century. The use of flax as a commercial crop has since declined due to the production of synthetic fibers.
Recently, there has been a steady increase in the uses and needs of flax due to an increase in demand for natural fibers. Flaxseed health benefits, thanks to their high levels of omega-3 fatty acids, have also played an important part in the resurgence.
Flax’s popularity as a garden filler stems from its striking yet fleeting blue flowers and semi-evergreen nature. Their strong stems look surprisingly delicate with clumps of blue-green leaves, creating an elegant look in garden landscapes.
The sought-after blue flowers perched on top of stems resemble small saucers. The flowers only bloom for a day, but perennial flax continues to flower for more than two months, sometimes longer if planted in the correct conditions.
While it is not considered an invasive plant, it does spread easily in the right conditions. It is a great companion for many plants but coexists best with other drought-tolerant plants like lavender. Perennial flax increases the biodiversity of your garden by attracting several beneficial pollinating insects. Adding to its allure is the plant’s drought and deer tolerance as well as its low-maintenance nature.
There are two ways to propagate flax – from seed or cuttings. Both are common methods but propagating through, cuttings are easiest. Let’s take a look at both methods, and what you can expect when you utilize either.
Propagating From Seeds
The best time to propagate from seed is during fall when most of the seed pods have browned. In the wild, perennial flax self-seeds, creating the wildflower fields often found across Europe.
You can simply leave your group of plants to spread naturally. However, if you’d like to control where it grows, gather seeds when the pods have turned brown and dried out to replant them. Gathering seeds is as easy as shaking the pods over a bowl or towel and picking up the fallen seeds.
Duplicate the natural propagation process by covering the seeds in a light dusting of potting soil and keeping the area cool until germination. You can also sow seeds indoors and transplant them later. Simply place the seeds in a tray filled with seed starting mix and sprinkle coconut coir over them. Replicate greenhouse conditions by covering the tray with a plastic bag and keeping the soil moist throughout the germination process.
Once the seeds have germinated (typically in about a month) they’re ready to be planted in beds or pots. Perennial flax grown from seeds typically flower within the first year.
Propagating From Cuttings
Taking cuttings isn’t the go-to method for propagating flax, but it’s a super quick and easy way to increase your stock. Flax is propagated by taking cuttings from new growth at the bottom of the plant. These are called basal cuttings, which come from growth shoots at the base of the plant around the crown.
It’s best to take cuttings in early spring when the plant is well established. Before cutting, ensure the stems are firm and approximately 4 inches long. There should also be an established underground stem.
Using sharp, clean sheers, cut the stem as close to the base as possible. To increase the chance of your cutting rooting, gently dip the cut end into some rooting hormone. This little trick is optional, but it does stimulate growth and protects the cutting from disease.
Plant individual cuttings in a container filled with a propagating mix and water thoroughly. Place the containers in a shaded place with greenhouse-like conditions. These conditions are simple enough to replicate by covering the containers with a plastic bag or heating the container from the bottom. Maintain humidity by keeping the soil moist and misting the plant throughout the rooting stage.
Rooting should take a few weeks. If the cutting offers some resistance when you gently tug on it, you can be sure roots have developed. You can also tell if you spot any new growth peeking through the drainage holes of the pot.
The best time to transplant stem cuttings is in summer. These new cuttings should flower the following spring.
The best time to plant perennial flax is in spring. Late summer or early fall will also work, but these times of year aren’t ideal. This delicate plant is easily found in local garden centers or nurseries. You can also transplant propagated flax once the seeds are mature enough or when the cuttings have developed roots.
When planting, ensure the planting hole is approximately 16 inches deep. Place your plant in the hole and refill with organic, rich, and well-draining soil. Increase the aeration and drainage of your soil by adding peat moss or coconut husk – a great sustainable substitute.
Once the root ball is covered with at least one inch of soil, gently press the soil down around the plant. Water your new plant thoroughly and keep watering consistently for several days until the plant is established. You can add a thin layer of organic mulch to help maintain soil moisture too.
These plants enjoy their space. When planting more than one plant, space them around 18 inches apart to prevent competition and overcrowding.
How to Grow
Before you jump into growing these plants, there’s some very important factors you’ll want to consider. They need the right amount of light and water. They also need the right type of soil, and fertilizer. Let’s not forget the proper growing zone, because even if you get all the other details right, not every plant is suited to grow in every part of the world. Let’s take a deeper look at what you can expect between each factor that’s important to this plant’s growth needs.
Perennial flax can tolerate some shade, but it needs plenty of sunlight to truly thrive. Plant in a spot that receives at least six hours of sunlight a day. While full sunlight is ideal, it will still flower its popular striking blue flowers in partial shade if all other conditions are met.
Part of this plant’s allure is its easy-going nature. While it is establishing itself in your garden, it needs plenty of water. However, once established, perennial flax needs less water, depending on the climate and soil type. Generally, it is considered a relatively drought-tolerant plant.
A good watering routine is critical not only for the health of your flax but for your entire garden. Water only in the morning and when the soil is dry to limit evaporation and prevent the soil from becoming too soggy. It’s also best to avoid overhead watering as it facilitates the spread of diseases.
Always water deeply and slowly to ensure the water evenly moistens the soil. This also allows the deeper roots to absorb water without overwatering your plant.
Perennial flax grown in cooler climates will tolerate longer periods between watering. Plants grown in hotter, drier climates, on the other hand, will appreciate water more often. Too long a period without water will cause the plant to become woody and may stunt growth. Too much water can cause root rot and fungal diseases, ultimately killing the plant.
When it comes to soil, perennial flax isn’t fussy, as long as it’s well-draining. Clay soil clings to water, so you won’t need to water your plant as often. Sandy soil drains quicker, requiring more frequent watering.
Despite not being fussy about soil type, loamy soil rich in organic matter is the goal. If your garden has heavy clay soil, you may want to add a few amendments to improve drainage. River sand and coconut husk are great organic materials that improve the drainage and aeration of your soil. Sandy soil can be amended with compost to improve moisture retention.
Climate and Temperature
Perennial flax grows well in USDA Zones 5-9 but prefers a more moderate climate. In most cases, the plant has no specific temperature or humidity needs. However, prolonged hot and dry periods can stunt growth and cause your flax to become woody.
In the right conditions, it will survive the winter. In some cases, it won’t even drop its leaves.
Perennial flax continues to live up to its low-maintenance nature by not needing frequent fertilizing. Typically, the organic materials added to the soil before or after planting provide sufficient nutrients for it to thrive.
If your soil quality is poor, you can add a layer of compost around the plant. It will slowly break down to improve soil structure and retain moisture in excessively sandy soil. Ensure this mulch layer is not too thick as these plants don’t appreciate waterlogged soil.
As you have surely noticed, perennial flax is an extremely easy-going plant, needing very little attention to thrive. The most important maintenance task is general garden hygiene and care.
Ensure no stray weeds are creeping around the base of your young plant. Weeds can quickly suffocate establishing plants and should be pulled out immediately. Take care not to damage the roots in the process. A thin layer of mulch may be necessary to squash the growth of any weeds.
Perennial flax does tend to appear leggy, so pruning may be necessary, simply for aesthetic purposes. While not needed, pruning is a healthy gardening habit to take up as it encourages flowering and new growth.
Some gardeners tend to cut their flax down by half following its first bloom. However, this isn’t usually needed and in some cases, it can impact the chance of reflowering throughout the season.
You can deadhead the plant throughout the season to keep it tidy. Deadheading is particularly important at the end of the season if you want to prevent the plant from self-seeding and spreading around your garden.
Flax may have a long history of commercial use, playing major roles in the textile, medicinal, and beauty industries. But, this gorgeous plant’s benefits and uses spread to home use too.
Commercially, seeds are harvested when seed capsules are dark, dry, and hard, while the stems have begun to yellow. Harvesting takes place in mid to late summer by windrowing. This is also the time when stems are gathered for extracting fiber.
Home gardeners luckily don’t need large farming machinery to gather seeds from their perennial flax. Gather seeds when the seed capsules have darkened and hardened by cutting a bunch of stems and shaking them vigorously. Shake the stems over a towel or large tray so you can easily gather the fallen seeds.
Next, sift through the other fallen plant debris, like leaves and sealed seed pods. Whole flax seeds should be left behind, either for propagation or for culinary use.
There are many plants in the Linum genus, each with its own characteristics. Many options suit different gardener’s needs and styles.
Linum Perenne, perennial flax, is grown across the world. They typically have the characteristic sky-blue cup flowers that gardeners are looking for. In many cases, Linum lewisii, a North American plant also known as prairie flax, is mistaken for L. Perenne. Both varieties grow to the same two-foot height and sport similar-sized flowers.
The main difference between the pair is that L. Lewisii is native to North America and is hardy at USDA zone 3. This plant is perfect for those in colder climates who love the delicate touch that flax plants add to gardens. L. Lewisii’s flowers can also bloom in different shades of blue, lavender, and even white.
Another cold-hardy cultivar is L. Perenne ‘Blau Saphir’ or Sapphire Blue Flax. Sapphire Blue Flax is known for its long bloom time when compared to other members of the perennial flax family. It’s perfect for gardeners wanting a true-blue look in their garden.
L. grandiflorum, also known as scarlet flax, doesn’t sport blue flowers. Instead, you’ll enjoy a palette of reds. Scarlet flax is perfect for adding a splash vibrance to your garden without losing that delicate touch.
Sometimes, gardeners don’t have the luxury of space or the perfect rock garden to add their perennial flax to. However, there are dwarf varieties like the Appar Blue Flax that grow to a compact 18 inches tall. They sport bright blue flowers that have a longer bloom time than most flax plants, making them a gorgeous fit for container gardens. Appar’s small size also makes them wonderful candidates for hanging baskets.
Flax plants aren’t generally bothered by pests, with most varieties being deer and rabbit resistant. Their stunning flowers tend to attract many pollinators like bees and butterflies to gardens. However, flax can attract aphids, snails, and slugs from time to time.
Luckily, these pests are easy to manage and eradicate, so don’t worry if you spot them near or on your flax plants.
Aphids are a common garden pest, often nestling in the undersides of leaves of the most unsuspecting plants. If left unattended, their colonies can easily run wild. But there are a few simple tricks to manage and avoid an aphid infestation.
Checking the undersides of leaves should be part of your daily gardening routine. If you notice an aphid or two, simply squish them between your fingers. You can also spray them off with a spray bottle or drop them into a bucket filled with soapy water.
Larger aphid colonies call for something stronger. Fill your spray bottle with a diluted mixture of neem oil, or another horticultural oil, and spray down your plants. While neem oil is often the go-to pesticide for aphids, it can deter other beneficial insects. You can also introduce aphid predators into your garden, like ladybugs, to prey on aphids and control the infestation for you.
Slugs and snails are just as easy to manage. Pick them off your fax and move them to another spot. You can keep them off your plants altogether by placing traps around the base of your plants too.
Flax is generally a worry-free plant, facing very little chance of encountering serious diseases. However, fungal diseases can affect these plants, especially if they’re constantly exposed to waterlogged soil.
The main fungal diseases that plague this plant are rust, fusarium wilt, and powdery mildew.
While the chances are slim, your bright blue flax may encounter rust fungus. Symptoms usually appear as orange, brown, or red spots on foliage. If left to spread, it can cause stunted growth, leaf drop, and reduced flowering. The fungus responsible for this disease is Melampsora lini, which can overwinter on plant debris. Rust can be managed by removing affected foliage and keeping the area around the plants free of any plant debris.
Fusarium wilt is a common fungus affecting many plants, including flax. It typically causes wilting and yellowing leaves and can kill off young seedlings. Unfortunately, this disease thrives in the soil and enters the plant through the uptake of water. The best way to deal with Fusarium wilt is by uprooting affected plants and destroying them. It’s also advised that you don’t grow flax in that spot again.
Powdery mildew is another common, but luckily less deadly, fungus. It causes a powdery white fungus to grow on flax foliage, inhibiting growth and making the plant appear unsightly.
Fungal diseases can usually be prevented by following a few tricks. Maintain good garden hygiene by removing plant debris around the base of your plants and only using clean gardening tools. Improve air circulation by pruning your flax. Also, leave sufficient space between these and any other plants in your beds. Be aware of your watering habits and avoid overhead watering or overwatering your plants.
Flaxseeds tend to stay fresh for quite some time, but it’s best to store them in an airtight container. A cool, dark, and dry pantry is the best place to store your perennial flax seeds. You can also place your seeds in the refrigerator for up to a year.
Depending on how you plan to use your seeds, you can either keep them whole or grind them. Both forms stay fresh either in the pantry or fridge.
They’re typically grown for their striking but delicate beauty. Their ability to thrive in low-quality soils makes them wonderful additions to rock gardens, or xeriscape landscapes. The cup-like flowers are a classic look, suiting cottage-style gardens and wildflower gardens alike. Their size also makes them the perfect border plant.
Their uses extend into the kitchen too. Its seeds are packed with omega-3s and can be eaten in a number of ways. Cooking the seeds releases a nutty flavor that pairs well with a variety of meals, including salads and soups. Or you could grind cooked seeds and toss the powder into your morning breakfast smoothie.
Perennial flax seeds do contain cyanide, which is destroyed during the cooking process. It’s not advised to consume raw seeds and always cook them well before consuming them.
Frequently Asked Questions
Is perennial flax invasive?
Perennial flax is not listed as an invasive species, but its self-seeding nature does cause it to spread quickly. You can control the spread of your plant by cutting it back at the end of every season. This encourages new, but controlled, growth.
Is perennial flax edible?
Perennial flax seeds are edible and are a great addition to many dishes. It’s best to cook the seeds first as they contain cyanide. The seeds have a nutty flavor, making them a delicious stand-alone snack or dish topping. You can also grind the seeds into a powder and add them to smoothies.
Perennial flax is a gorgeous plant with a low-maintenance nature that suits new and laid-back gardeners alike. Their striking blue flowers and delicate-looking stems add a touch of elegance to any space. It is generally a worry-free plant that requires very little to thrive. As long as it receives plenty of sunlight and its soil remains relatively dry, perennial flax will flourish in your garden.