Amsonia Plant Growing & Care Guide for Gardeners

In this Gardener's HQ guide, we'll explore cultivating Amsonia plants in your garden, indoor spaces, and other settings.

Blue Star: Cultivation & Garden Use

The common name for the Hardy perennial Amsonia is Blue star.

It typically flowers in the summer.

Amsonia
Thomas G. Barnes @ USDA-NRCS PLANTS Database / Barnes, T.G. & S.W. Francis. 2004. Wildflowers and ferns of Kentucky. University Press of Kentucky

Some of the latin names include Amsonia hubrichtii, Amsonia tabernaemontana, and Amsonia hubrechtii. Common names include amsonia blue and star amsonia.

Description of Blue Star

Amsonia Blue Star are attractive medium sized plants that can grow from 60 to 90 cm in height. As the name suggests Blue Star has blue star shaped flowers; these grow on long stems. these plants are ideal for beds that are located in the shade.

Blue Dogbane
Amsonia (Blue Dogbane) photograph by Dendroica Cerulea.

Amsonia Plant Species

Amsonia tabernaemontana (Eastern bluestar)

The Amsonia tabernaemontana plant is a perennial growing up to 36 inches (90 cm) in height. It is commonly known as the Eastern bluestar. The plant features narrow, willowy leaves, and blooms with clusters of star-shaped, light blue flowers.

The Eastern bluestar is often grown in gardens for its attractive foliage and spring blooms. It thrives in full sun to partial shade, and prefers well-drained soil. This plant is oft used in borders, native plant gardens, or for naturalized areas.

Amsonia ciliata (Fringed bluestar)

The Amsonia ciliata perennial reaches up to 24 inches (60 cm). This plant is known as Fringed bluestar. It is characterized by fringed leaves and carries clusters of blue, star-shaped flowers.

Fringed bluestar is grown in gardens for its vibrant spring blooms and attractive foliage. It emjoys a location that has full sun to part shade, and prefers well-drained soils. This plant is usually used in borders, wildflower meadows, or as a part of a pollinator-friendly garden.

Amsonia hubrichtii (Arkansas bluestar)

The Amsonia hubrichtii plant, reaching up to 36 inches (90 cm), is commonly referred to as the Arkansas bluestar. Noteworthy features include feathery, thread-like leaves and clusters of light blue, star-shaped flowers.

As with other Amsonia plants, Arkansas bluestar is grown in gardens for its attractive foliage and star-like spring flowers. Plants enjoy full sun to partial shade areas, and prefer a soil which has medium moisture, and well-drained soils. It makes a perfect choice for borders or naturalized areas.

Amsonia illustris (Ozark bluestar)

Commonly known as the Ozark bluestar, the Amsonia illustris plant is a perennial that can grow up to 36 inches (90 cm) in height. This plant has oblong to lance-shaped leaves and carries clusters of star-shaped, light blue flowers.

The Ozark bluestar is often grown in gardens for its showy flowers and attractive foliage. Plants prefer to grow in a part of the garden that has full sun to partial shade. it requires good drainage. It makes a great addition to borders, native plant gardens, or for use in naturalized areas.

How to Grow Amsonia

It is best to sow Amsonia just below the soil surface, with a spacing of 20 to 30 inches (50 to 75 cm) in the middle of spring, or the autumn.

Blue star prefers partly shady conditions, but can be grown in full sunlight as long as it is kept moist. The soil should be cool and moist. Amsonia requires between four and six weeks to germinate.

If growing indoors it is best to start seeds off nine to eleven weeks before planting outside in the late spring. Ideally they should be grown in peat pots at a temperature of 14 to 18 degrees centigrade when growing inside.

Caring for Blue Star and other Amsonia in the Garden

Amsonia plants requires light pruning and watering in the driest months of summer.

Amsonia Growing and Care Guide

Common Names: Blue star, Bluestars, Gray Amsonia.
Life Cycle: Hardy perennial.
Height: 8 to 36 inches (20—90 cm).
Native: North America, East Asia, Eastern Mediterranean.
Growing Region: Zones 4 to 9 (Amsonia hubrichtii 5—8).
Flowers: Late spring and early summer.
Flower Details: Pale blue, white, green. Clusters. Tubular. Flat faced stars. Five petals.
Foliage: Herbaceous. Woody. Linear to lance-shaped/ pointed ovals. Lower leaves wider than higher ones. Clump forming.
Sow Outside: Cover seed. Mid-spring or autumn.
Sow Inside: Germination time: four to six weeks. Peat pots. Temperature: 58 to 65°F (14—18°C). Start two to three months in advance. Transplant outdoors following any chance of a last frost. Space at 20 to 30 inches (50—75 cm).
Requirements and care: Shade for best colors, can tolerate full sunlight if soil is kept constantly moist. Regular watering during dry periods. Good drainage. Prefers a cool moist soil, but the type is not overly important. Slow growing. As stems can flop when grown in complete shade cut back to six inches (15 cm) following blooming. Propagate: by dividing in the autumn.
Family: Apocynaceae.
Closely Related Species: Adenium, Allamanda, Amsonia, Asclepias, Nerium, Pachypodium, Wrightia, Vinca
Miscellaneous: Named after John Amson, the American physician and Mayor of Williamsburg.
Milky sap is a skin irritant (protects plants from slugs and snails).
The European form (Amsonia orientalis) is commonly grown in gardens and is often wrongly named as Rhazya orientalis in garden centers and nursery’s.
In Northern America the Arkansas blue star (Amsonia hubrichtii) is the most frequently grown species in gardens.
Attracts butterflies. Deer resistant plant.

Common Questions

How many members does the Amsonia genus have?

The Amsonia genus includes around 20 species.

Do members of Amsonia make a good garden or landscaping plant?

Yes, Amsonia is known for its star-shaped flowers and attractive foliage. It is often used in perennial borders.

Which Amsonia species are most frequently grown by gardeners?

Amsonia tabernaemontana (Eastern Bluestar) is commonly grown due to its long bloom time and striking autumn color.

Are members of the Amsonia fragrant?

Amsonia plants are not typically known for their fragrance.

What is the perfect location to grow Amsonia?

Amsonia prefers full sun to partial shade and well-drained, fertile soil.

Is Amsonia invasive in the USA, if so in which states?

Amsonia is not considered invasive in the USA.

How do I remove Amsonia from my garden?

Removal can be done by pulling or digging up the plants, ensuring to get all roots to prevent regrowth.

Summary

The Amsonia genus, also known as Blue Star, consists of perennial plants appreciated for their elegant and delicate blue flowers. Native to North America, Amsonia plants are valued for their attractive foliage, which turns golden in the fall. They thrive in well-drained soil and prefer full sun to partial shade exposure. Regular watering is important during the growing season to promote healthy growth and flowering.

Growing Amsonia is relatively easy as they are low-maintenance plants. These plants can be propagated through division or by planting seeds. Amsonia species are commonly used in borders, rock gardens, or as accent plants, adding a touch of elegance and beauty to the landscape. With their lovely blue flowers and golden fall foliage, Amsonia creates a striking visual display and attracts pollinators, making it a favorite choice among gardeners looking to create visually appealing and wildlife-friendly gardens.

I hope that you enjoyed this guide on Althaea. You may also enjoy the following garden growing guides: Mazus Plant, How to grow Malva and Hibiscus plants.

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