(Editor's Note: This article was originally published on October 4, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
Sea pinks, also known as thrift, are a group of low-growing perennials from the genus Armeria. In the wild, these plants typically grow along coastal cliffs and salt marshes. There is some debate on how many species exist; some authorities claim some 80 species while others lump many of these into about 10. The vast majority of species and forms are native to the Mediterranean region with only one species that extends into North America. Only a limited few are commonly grown as garden plants since most are relatively tender (zone 8) and require a Mediterranean climate to thrive. However, three species are quite hardy and make wonderful perennials for the rock garden, containers or front of the border. These include A. maritima, A. pseudarmeria (aka A. formosa) and A. caespitosa (aka A. juniperifolia).
By far the most popular is the common sea pinks, A. maritima. This species is also the only one that is found, in various forms, across the entire northern hemisphere. It is very hardy, surviving to zone 2-3. Plants form grass-like tufts with flower stems arising 15-25 cm. Each stalk is topped by a spherical head of white or pink-shaded flowers. They bloom mostly in late spring-early summer but if dead-headed, will often produce a second flush later in the season. This thrift is among the easiest of perennials. Any sunny, well-drained site suits them fine. They are very wind, drought and salt-tolerant and actually perform better on rather poor soils. They can even survive in soils with heavy metals! Do not fertilize them as it results in soft growth, floppy flower stalks and an increased incidence of root-rot.
There are about 30 named forms of A. maritima, however, only a handful are readily available. Among the more common are ‘Alba' (white), ‘Bee's Ruby' (brilliant pink), ‘Bloodstone' (cherry-red), ‘Cottontail'(white), Laucheana' (bright pink), ‘Dusseldorf's Pride' (bright pink), ‘Ruby Glow' (reddish-pink), ‘Splendens' (light pink) and ‘Vindictive' (rose-pink). Recently, there have been two more excellent introductions. ‘Rubrifolia' has wonderful purple-red foliage and contrasting magenta-pink flowers. I grow mine next to Sedum acre ‘Aureum' and red-coloured Sempervivum. The newest thrift on the market is called ‘Nifty Thrifty'. This selection has variegated foliage and contrasting rose-pink flowers. It looks especially nice planted next to low-growing, purple-foliaged sedum like ‘Vera Jamieson' and S. cauticola ‘Lidakense'.
Also quite popular is the relatively giant thrift called A. pseudarmeria (aka A. formosa). This species also produces a tuft of grass-like foliage but the foliage is larger and stiffer than that of A. maritima. The flower stems are relatively tall and stiff, reaching 45-60 cm and the flower heads are a bit larger. It makes an admirable cut-flower. The flowers, like those of A. maritima, are available in white and pink shades. While not as floriferous as the common sea pink, they do bloom over a longer season. This species appreciates a hot site and prefers drier conditions than A. maritima. They are rated for zone 2-3 as well. The ‘Joystick' and 'Bee' series are probably the most popular. Strangely, I have tried this species several times in my zone 5b and never had any luck overwintering them, while common sea pinks grows like a weed! I assume my excessively wet climate with cool summers is just not to their liking.
The other relatively popular species is the dwarf or Spanish thrift, A. caespitosa (aka A. juniperifolia). This species forms a dense tuft of short, almost needle-like foliage and heads of white (‘Alba') or light pink (‘Bevan's Variety') flowers on short 5 cm stems. It is a choice plant for the rock garden. This species is not as hardy as the previous two, being rated for zone 5. It also hails from alpine regions rather than coastal. This one demands excellent drainage and prefers to have its crown kept on the dry side during winter. That is a challenge in my area where we get 60" of rain per year! I invert a clay flower pot over mine for the winter months and it comes through with flying colours, so be creative and create microclimates and shelters, you may be surprised! This species is among the earliest thrift to bloom, but like the other thrift, prompt dead-heading will result in sporadic blooms later in the season.
If you have never tried thrift, I highly recommend you do. Even when not flowering, the neat and tidy habit of these plants is very desirable. They are indispensable for the rockery and ideal for alpine troughs, containers, perennial borders and seaside gardens. Look for them in your local garden center or through specialty alpine plant nurseries.
Images courtesy of PlantFiles