Linum perenne
perennial flax
linaceae
Sky-blue flowers; small narrow leaves
18–24 in. high; 12 in. wide
Full sun
Blooms May–July
Zones 5–8
pruning Each individual flower lasts
only 1 day, and the old flower petals
drop neatly off the plant. Young plants
may bloom for a long period without
pruning. With age, plants usually get
straggly by midsummer, in which case
they can be sheared back at this time
by half to two-thirds for production of
new feathery growth and often a
smaller rebloom. If plants open up
again they may need another lighter(by a third) shearing. Keep plants
moist after pruning, particularly in hot
regions, for better regeneration of
foliage. Perennial flax may seed
strongly; allowing some seeding can
ensure permanence of this short-lived
perennial in the garden. If seed is
mature when plants are cut back,
sprinkle some seeds onto the soil in
the desired location to obtain seed-
lings for the following year. Shearing
plants before flowering by half in early
May can help produce fuller plants.
This is useful for newly planted flax as
well, which is often thin and spindly.
other maintenance Avoid poorly
drained soil, which will shorten the
life of flax. Alkaline, dry soils are best.
Division of the coarse and sparse roots
is usually unsuccessful.
related plantS Linum lewisii,
prairie flax (zones 3–9), could be
described as the western United States
version of the European L. perenne, and
enjoys the same conditions. Plant it in
dry soil in a sunny spot (the flowers
don’t open in shade or on cloudy days).
It is susceptible to rot if winter
drainage isn’t perfect and is short-lived
even under the best of circumstances.
It will reseed to maintain its presence
in the garden. Prairie flax grows 1–2 ft.
tall and is topped with sky-blue
blossoms in late spring and may
rebloom later in the year if dead-
headed after the first wave of flowers.
It shouldn’t need staking. Watch for
slugs and aphids.
Linum narbonense, Spanish blue flax
(zones 5–8), is considered by some to
be longer lived than L. lewisii or L.
perenne, but still falls under the rubric
of the short-lived perennial. It tops out
at 2 ft. and displays the sky-blue
blossoms that are typical of the genus.
Spanish blue flax likes a sharply
drained but not bone-dry position in
full sun and holds its wispy stems up
without staking unless sited in
too-rich soil. Deadheading may bring
another round of flowers. Cut plants
down in early spring before the new
growth emerges.Linum perenne