How big does Perennial flax grow?

About 50 cm × 30 cm after ten years (height × width). Its ultimate size is 30–60 cm × 25–45 cm.

What soil does Perennial flax grow in?

It tolerates these soils: average garden soil, sandy, calcareous.

How much water does Perennial flax need?

Water need: low. Drought tolerance: high.

Perennial flax

Linum perenne

Perennial flax (Linum perenne) is a perennial that reaches 50 cm × 30 cm after ten years. Light: full sun, part shade. Drought tolerance: high.

Illustration of Perennial flax — An illustration of the typical shape of the mature plant, not a photo.

What it's good for, and what it isn't

Perennial flax carries fresh sky-blue flowers on thin, flexible stems with blue-green leaves from late spring into midsummer; each flower lasts only a day and on hot days drops by noon, but new ones open every morning. It is happiest in sunny, dry, lean, sandy or stony, limy soil and copes well with heat and drought, so it suits rock gardens, gravel beds, banks and border edges. It is a short-lived perennial that renews itself from seed; cutting some stems back by half midway through flowering keeps it compact and extends the show.

Watch out for

It is short-lived and wears out after a few years. In heavy clay it roots shallowly and often dies in winter, and it cannot take standing water or frequent watering. Slugs like to eat young plants, and aphids, cutworms and grasshoppers occasionally damage it. In shade or rich soil it sprawls and flowers poorly. It self-seeds readily, so cut it back after flowering if you do not want seedlings.

Key facts

Light: Full sun, Part shade
Water need: Low
Care: Medium
Size after 10 years: 50 cm × 30 cm
Hardiness: down to -29 °C
Foliage: Semi-evergreen
Flowering: J F M A M J J A S O N D May–August, blue

Group	Perennial
Light	Full sun, Part shade
Size after 10 years	50 cm × 30 cm
Ultimate size	30–60 cm × 25–45 cm
Hardiness	down to -29 °C (USDA 4, RHS H7)
Soil	Average garden soil, Sandy, Calcareous
Foliage	Semi-evergreen
Flowering	May–August, blue
Water need	Low
Drought tolerance	High
Maintenance	Medium
Root aggressiveness	Low
Suckering	no data
Spreading	Medium
Distance from buildings	no data
Distance from paving	no data
Litter	not typical
Planting distance	30 cm
For dogs	no data
For cats	no data
For children	Mildly toxic (uncertain)
Typical price	no data

Toxicity data is for information only. If your pet or child has eaten a plant, contact a vet or a doctor.

Frequently asked questions

Data updated: October 19, 2026 · How our data is made

Appears in these lists

Perennials for part shade Perennials for full sun Perennials that flower all summer Drought-tolerant plants Drought-tolerant perennials Drought-tolerant plants for sandy soil Perennials for pollinators Plants for a Mediterranean garden