Linum perenne, perennial flax, is a long-flowering garden perennial that is easy to grow and blooms from spring into early summer. The clear light blue flowers are produced by the dozens for six to eight weeks and are especially at home naturalized in the perennial or cottage garden.
Perennial flax is also known as blue flax and prairie flax.
It is often grown as an annual or as a short-lived perennial. The term ‘short-lived perennial’ is a bit of a mystery. I often hear this description when cardinal flower is discussed. My translation is that the perennial may peter out for no particular reason that the gardener can discern…or maybe the plant is borderline winter hardy.
It may be a fair description of a species, but when I hear nurseries use the term short-lived perennial it sounds like a preemptive excuse for a weak growing plant. This is unfair I think. Some plant species’ life-cycles do not depend on great longevity. Considering perennial flax grows quickly and reseeds profusely, it would make sense that it does not need to be biologically adapted for individual plants to survive years in the natural landscape.
Perennial flax can be grown from seed by the way.
Linum perenne is drought tolerant.
Perennial flax grows one to two feet tall in a clump a foot or so wide. Perennial flax has a strong preference for sun. The leaves have a fine texture and are not particularly memorable. The flowers are a different story. Flowers are cornflower blue with five petals. They are relatively small, perhaps an inch across at most.
Perennial flax is considered drought tolerant and, according to Cornell University, deer do not eat it.
Growing perennial flax in the garden
It is native to Europe and winter hardy zones 5-8 in the United States. Linum perenne is easy to grow, being relatively drought tolerant and not particular about soils. The only issue is clay; typical of many perennials, Linum perenne may die during winter in poor-draining heavy soils. It prefers sun and well-draining loamy or light soil conditions.
It reminds me somewhat of a blue (and taller growing) version of some of the threadleaf coreopsis cultivars. I would handle deadheading in a similar fashion with the two species. Deadheading extends bloom considerably. Do not deadhead individual flowers. Instead shear perennial flax back by a half or so as the current flush of blooms begins to wane.