PEI’s salt marshes are among our most under-appreciated habitats: they’re wet, smelly, buggy, and have few showy, conventionally-attractive flowers. They’re also among our most important spaces and home to the lovely Sea Lavender (Limonium carolinianum).
Despite its name, our native Sea Lavender is unrelated to the non-native aromatic Lavenders (Lavandula spp.) used in soap, perfume, and essential oil. Sea Lavender has no real scent, but its beautiful purple-blue flowers dry well and so this plant is often harvested for dried flower arrangements, sometimes in commercial quantities. As a slow growing perennial – it takes an average of eight years to mature to flowering stage – Sea Lavender is sensitive to overharvest. One Nova Scotia study estimated the maximum sustainable harvest to be about one plant for every six found. If you collect Sea Lavender, please do so in moderation.
Salt mashes are tough places for plants to make a living, which is why so few do. Water-logged soils are low in oxygen, making it hard for roots to breathe, and the high concentration of salt in the soil and water would kill most species.
Like many coastal plants, Sea Lavender roots have lots of spongy tissue (called ‘aerenchyma’) that stores oxygen and helps the plant breathe. Leaves and stems have specialized glands that sequester excess salt and push it back out to the surface of the plant, ensuring the proper osmotic balance is maintained internally. If you run your hand over the surface of Sea Lavender, you’ll find it covered in salt crystals. That’s not from evaporated sea water, but rather the work of those all-important salt glands. Thanks to these adaptations, Sea Lavender can tolerate salinity of up to 3% (human blood, sweat, and tears average less than 1% salt).
Sea Lavender has traditional medicinal uses and hosts an assortment of endophytes – fungi and bacteria that live inside the plant in a mutually-beneficial relationship. In some plants, endophytes are known to produce chemicals that not only protect the plant against disease and predators but also have useful medicinal properties for humans.
Recent research has isolated a number of Sea Lavender’s endophytes and found that they produce more than two dozen biologically-active compounds with properties including antibacterial, anticancer, anticoagulant, anti-diarrhoeal, anti-inflammatory, antipsychotic, and sedative, among others. That doesn’t mean you should harvest Sea Lavender to cure all that ails you but does mean this plant and its endophytes will likely be the subjects of further research.
Sea Lavender is common on the Island and is a beautiful and unique part of PEI untamed!
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