Species Focus: Iris pseudacorus


Otherwise known as yellow flag, water flag, yellow iris, sword-grass and lever, Iris pseudacorus is a rather lovely botanical. A prominent feature of pond margins, ditches and other damp areas across much of Britain, this radiant iris adds a touch of glamour to soggy areas nationwide. The plant – growing up 1.5 meters in height – a personal favourite of mine since childhood; since I first took it upon myself to transplant a specimen into my garden pond, much to the delight of the various pollinators inhabiting my small yard.

Thought by some to be the original fleur-de-lis – a common symbol of medieval heraldry; the daffodil-like yellow blooms of I. pseudacorus, with their sickly sweet scent, provide an irresistible draw to a whole manner of pollinating insects – from bees to hoverflies – while the elongated leaves provide food for the larvae of the aptly named Iris Sawfly Rhadinoceraea micans. All of which goes without mentioning the valuable cover provided by the densely packed foliage and sprawling roots of this waterside species – perfect for amphibians, fish and aquatic insects seeking cover in an effort to avoid the gaze of nearby predators. The iris is a superb addition to any wildlife garden; while also looking rather exquisite, particularly in the Summer sun.

The human uses for I. pseudacoru, traditionally, include the use of the rhizome as a herbal remedy – most often as an emetic; while the plant in its entirety is commonly used as a form of water treatment. With its roots able to take in heavy metals and toxins that would quickly kill other aquatic vegetation. It’s ability to grow in waters boasting a low Ph level also make it a useful indicator of water quality and ecosystem health.

Fact: the wavering flowers of the iris were once thought to resemble flags blowing in the breeze, hence the name “yellow flag”.

Folklore: According to legend, Clovis was the first person to adorn his clothes with iris heraldry.  Later becoming the king of the Franks, he was responsible for forcibly evicting the Romans from Northern Gaul, thus establishing the yellow flag as a symbol of Frankish pride. Louis VII would later wear similar heraldry in his crusade against the Saracens.



  1. Zinzi says:

    Beautiful flower 🙂 thank you for sharing a little bit of the folklore too! Always one of my favourites to read about 🙂

    1. James Common says:

      Mine too! Might try and make these short posts a regular thing 🙂

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