Amsonia is a genus of about 20 species of perennials in the family Apocynaceae, mainly native to North America.
Amsonia has star-shaped flowers and multiple leafy stems growing from a semi-woody rootstock. The flowers are tubular at the base, with five sharply pointed petals. Amsonia can be used as a single specimen plant or in mass plantings. These plants look handsome in a perennial garden bed, as a border plant or in a cottage garden. They are also beneficial in attracting bees and hummingbirds to your garden. Not only are they easy to grow, but these plants are easy to care for as well.
The genus was named in honor of Dr. Charles Amson, an 18th century physician from Virginia.
The common name “Blue Star” refers to the star-shaped flowers.
Amsonia represents endurance, strength and determination.
Interesting facts about Amsonia:
Is Amsonia Poisonous?
Like other members of the dogbane family (Apocynaceae), Amsonia has a white, milky sap that causes this plant to be unpalatable to insects, rabbits, deers and many other garden pests.
But chemical compound in its milky sap causes a variety of skin irritations on humans and animals. However, the milky sap is not considered to be harmful to humans, although people with latex allergies are advised to wear gloves when handling the plant.
There are many cultivars of Amsonia and the gardener who wants to grow them can surely find a cultivar to suit his needs. Amsonia ‘Blue Ice’ is one of the most popular cultivar. It is an erect, clump-forming plant with star-like, dark blue flowers atop erect, leafy stems. It has the showiest and most spectacular flowers of all Amsonias.
Another popular cultivar is Amsonia tabernaemontana ‘Short Stack’. It is a dwarf variety that typically grows to only 25 cm (10 inches) tall. This cultivar has sky blue flowers and bright green leaves that turn golden yellow in fall. It is an easy-to-grow plant that looks great in rock gardens, moist borders and mixed perennial beds.
The flowers are usually white but may be blue, pink and purple.
These plants grow up to 120 cm (4 ft) tall, depending on the variety. There are also dwarf varieties that only reach 10 cm (4 inches) in height.
Amsonia prefers rich, moist and well-drained soil. The ideal soil pH is between 6.0 and 7.0.