Amsonia elliptica

Flower name
Amsonia elliptica
Scientific name
Amsonia elliptica
Aliasアムソニア, Amsonia, ブルースター, Japanese Bluestar, 丁子草, ハナチョウジ, 花丁子, アムソニア・エリプティカ
Place of originJapan and East Asia
Place of floweringWetlands, Cut flowers, flower arrangement, Potted flower, River, pond
Flowering seasonApril, May, June

What is Amsonia elliptica

Amsonia elliptica , the Choju-sou or Japanese Bluestar, scientific name: Amsonia elliptica, is a semi-hardy and non-heat resistant perennial herb belonging to the Apocynaceae family and the Amsonia genus, native to Japan and East Asia. It is also known as Hanachoju (flower choju) or Amsonia In Japan, it grows in wetlands from Hokkaido to Kyushu.

It grows upright with a height of 30-70 cm. The leaves are lanceolate to elliptic and alternate, initially green but turn yellow in autumn. From April to June, it produces 3-10 pale blue flowers with a diameter of about 1.5 cm arranged in a spreading inflorescence on the flower stem. The flower corolla is star-shaped when viewed from above and has a five-pointed star shape when viewed from the side. After flowering, it produces two slender cylindrical follicles about 5 cm long. With its pale flower color and sparse flower numbers, and dense foliage, it exudes a modest Japanese-style atmosphere. It is used for gardening and as a cut flower.

Due to the decrease in its natural habitat of wetlands, it has been designated as an endangered species. Being a member of the Dogbane family, the entire plant contains alkaloids, making it a poisonous plant with a toxic milky white liquid that exudes when the leaves or stems are broken.

Varieties of Amsonia
Besides Choju-sou (A. elliptica), which is native to Japan and East Asia, there are other species like the narrow-leaved Choju-sou (A. angustifolia) native to North America, the willow-leaved Choju-sou (A. tabernaemontana) native to eastern and southern North America, and the thread-leaved Choju-sou (A. hubrichtii) native to central and southern North America. These species have progressively narrower leaves. The willow-leaved variety has larger flowers with a diameter of 2.5 cm.

Origin of the Name Amsonia elliptica
The genus name is a dedication to the American botanist Dr. Ch. Amson, while the species name "elliptica" refers to the elliptical shape of the leaves compared to other varieties.

Common name: Amsonia elliptica (Amsonia elliptica), Scientific name: Amsonia elliptica, Aka: Amsonia, Japanese Bluestar, Growth habit: Perennial herb, Taxonomic classification: Angiosperms, Eudicots, OrderGentianales, Family Apocynaceae, Genus Amsonia, Native to: Korean Peninsula, China, East Asia including Japan, Habitat: Wetlands, Height: 30-70 cm, Leaf stalk: Very short, Leaf color: Green (spring/summer) → Reddish in autumn, Leaf shape: Lanceolate to elliptic, Leaf length: 6-12 cm, Leaf width: 1-2 cm, Leaf arrangement: Alternate, Flowering period: April to June, Inflorescence type: Scattered cymes, Corolla diameter: 1.5 cm with flat spreading, Flower color: Pale blue, Calyx: 5-lobed, Fruit type: Capsule, Fruit shape: Two long cylindrical, Fruit length: 5-6 cm, Uses: Ornamental planting, Cut flower, Note: Entire plant is toxic, Endangered species.