Scientific name: Helmholtzia glaberimma
Common name: stream-lily, flax-lily
Plant type: Perennial herb
Environment: Part shade to shade with moist to wet soil
Bloom: Large panicles of white or pink flowers
Uses: Perfect for a shady spot in the garden that remains relatively moist, will also do well in a container
Helmholtzia glaberrima, commonly known as the flax-lily or stream-lily, is a large herb from eastern Australia. A member of the Philydraceae family, Helmholtzia is a monocot, or a monocotyledon. This term means that these plants only have one seed leaf. Additionally, most monocots will have flower parts in multiples of three, parallel leaf veins, and will lack woody growth. And though lilies are also monocots and often have these same characteristics, the common names of H. glaberrima are misleading, as it is not a member of the lily family, the Liliaceae.
The genus Helmholtzia is very small with a limited distribution. There are only 3 species in the genus, two of which, including H. glaberrima, occur in eastern Australia. The third species, H. novoguineensis, is found just across the Torres Strait in Papua New Guinea. More limited still, Helmholtzia glaberrima is found in an area smaller than 100 km in the McPherson mountain range in the states of Queensland and New South Wales. Though this is a quite small area, the species is abundant within it.
In this range, H. glaberrima is limited to waterlogged areas, particularly high elevation creek banks. Additionally, the species thrives on the volcanic soils found in this region. These soils are the result of the inactive Tweed Volcano, which last erupted approximately 23 million years ago.
The genus Helmholtzia was named for the German scientist Hermann von Helmholtz, best known for his work in vision research and thermodynamics, by the Government Botanist of Victoria, Australia, Ferdindand von Mueller in the 1800s. The species name glaberimma is derived from the Latin term glaber, meaning smooth or hairless, referring to the smooth foliage of the plant.
H. glaberrima is a large perennial herb with leaves that can grow up to 7 feet tall. Additionally, it has large panicles of white or pink flowers. Given its native habitat, the stream-lily will do best in shady parts of the garden that remain a bit moist or even inundated for a time. If placed in a sunnier spot, it will require more frequent watering.
IN BLOOM CONTRIBUTORS: Text by Victoria Stewart. Photos by Joanne Taylor.