Blue Flag – Iris versicolor, medicinal and ornamental herb plant

Blue Flag Iris (Iris versicolor) is a hardy, moisture-loving perennial that brings a splash of vibrant blue-violet to the garden. It thrives in permanently moist or boggy soils, making it perfect for planting along ponds, dams, or water features. With regular irrigation, it can also grow happily in standard garden beds, rewarding you with masses of graceful flowers in spring and summer.

Traditionally valued by North American First Nations peoples, Blue Flag has been used in herbal medicine for centuries. Modern herbalists prepare the dried root to support the liver, encourage detoxification, and promote healthy circulation, digestion, and fluid balance. Poultices made from the root have also been applied to ease rheumatic joints.

👉 The root must be harvested and dried before use because, when fresh, it contains compounds that can cause nausea or irritation. Drying reduces these effects and allows the herb to be prepared safely for traditional use.

More than just a useful herb, Blue Flag is also a striking ornamental. Its sword-like leaves and tall, colourful blooms make it a wonderful choice for mass planting at the water’s edge or as a feature in a cottage, herb, or permaculture garden.

Bring beauty and tradition together in your garden with this unique plant that’s as eye-catching as it is historic.

In Australia, Iris versicolor grows best in cool to temperate zones with reliable moisture, especially Tasmania, southern Victoria, cooler NSW highlands, and similar climates. It dislikes tropical heat and hot, dry inland areas. It hasn’t flowered in my Port Stephens garden so far, maybe a colder climate is needed to induce flowering. However, it’s the roots that are used in herbalism and while I would love the flowers I still get roots in the warmer climate.