Amsonia Plant Care: Tips For Growing Amsonia Plants

Amsonia Plant Care: Tips For Growing Amsonia Plants

By: Jackie Carroll

For those looking to add something unique to the flower garden as well as seasonal interest, consider growing Amsonia plants. Keep reading to learn more about Amsonia plant care.

Amsonia Flower Information

The Amsonia flower is a North American native with a long season of interest. It emerges in spring with willowy foliage that forms a neat, rounded mound. In late spring and early summer, loose clusters of half inch (12.6 mm.), star-shaped, blue blossoms cover the plant, giving rise to the common name blue star.

After the flowers fade, the plant continues to look good in the garden, and in fall, the foliage turns bright yellow-gold. Amsonia blue star plants are at home along woodland streams or in cottage gardens, and they also do well in beds and borders. Amsonia makes an ideal addition to blue garden schemes too.

The two species that are readily available from nurseries and seed companies are willow blue star (A. tabernaemontana, USDA zones 3 through 9) and downy blue star (A. ciliate, USDA zones 6 through 10). Both grow up to 3 feet (90 cm.) tall and 2 feet (60 cm.) wide. The main difference between the two is in the foliage. Downy blue star has shorter leaves with a downy texture. Willow blue star flowers are a darker shade of blue.

Amsonia Plant Care

In soils that are constantly moist, Amsonia prefers full sun. Otherwise, plant it in light to partial shade. Too much shade causes the plants to sprawl or flop open. Ideal Amsonia growing conditions call for a humus-rich soil and a thick layer of organic mulch.

When growing Amsonia plants in sandy or clay soil, work in as much compost or well-rotted manure as possible to a depth of 6 to 8 inches (15 to 20 cm.). Spread at least 3 inches (7.5) of organic mulch such as pine straw, bark or shredded leaves around the plants. The mulch prevents water evaporation and adds nutrients to the soil as it breaks down. After the flowers fade, feed each plant a shovelful of compost and cut back plants growing in shade to a height of 10 inches (25 cm.).

Never allow the soil to dry out, especially when the plants are growing in full sun. Water slowly and deeply when the surface of the soil feels dry, allowing the soil to absorb as much moisture as possible without becoming soggy. Discontinue watering in fall.

Good companions for Amsonia blue star plants include Bridal Veil astilbe and wild ginger.

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Blue Star Amsonia

Another name for the Blue Star Amsonia shade plant is Dog Bane or Dogbane, they offer different decorative functions depending upon the season, and as such are highly attractive plants right through the warmer months of the year.

Bluestar Amsonia is native to southern lands, and displays many clusters of gorgeous pale blue star shaped flowers.

The flowers appear from spring to early summer, but the attraction of this shade plant does not fade with the flowers.

The beautiful lace like foliage of Amsonia will last until fall and consists of lovely green needle like or lance shaped leaves. These turn an exquisite golden yellow color in the fall. So you see the plant will remain ornamental all through the warm seasons.

Flowering lasts for just about two weeks in early summer the plants reach a height of between one to three feet, and spread out up to three feet. Bloom time lasts to around 1 month.

This is a nice shade plant for a garden, even though it is slow growing, because it will not invade the rest of the garden, instead growing quietly in the area allotted to it.

"Blue Star Amsonia offers three mini seasons of interest.

The blue flowers in Spring to early Summer, then beautiful lacy foliage till Fall when the foliage turns a gorgeous golden colour. This colour will last for a fairly long time."

Plants→Amsonia→Blue Star (Amsonia hubrichtii)

Common names:
(2) Blue Star
(2) Narrow Leaf Blue Star
(2) Threadleaf Bluestar
Hubricht's Bluestar
Arkansas Amsonia
Hubricht's Amsonia
General Plant Information (Edit)
Plant Habit: Herb/Forb
Life cycle:Perennial
Sun Requirements:Full Sun
Full Sun to Partial Shade
Water Preferences: Mesic
Soil pH Preferences:Neutral (6.6 – 7.3)
Minimum cold hardiness:Zone 4a -34.4 °C (-30 °F) to -31.7 °C (-25 °F)
Maximum recommended zone:Zone 9b
Plant Height :2 to 3 feet
Plant Spread :2 to 3 feet
Leaves:Good fall color
Other: Best fall foliage color usually occurs in full sun, but flowers generally last longer if given some afternoon shade in hot sun areas. The unique foliage remains bright green throughout summer, but changes to a stunning gold in fall.
Flower Color:Blue
Other: Powder blue
Flower Time:Late spring or early summer
Uses:Cut Flower
Wildlife Attractant:Bees
Resistances:Deer Resistant
Rabbit Resistant
Humidity tolerant
Drought tolerant
Propagation: Seeds:Other info: Sow seeds in spring
Propagation: Other methods:Division
Containers:Suitable in 3 gallon or larger
Needs excellent drainage in pots
Miscellaneous:Tolerates poor soil
Awards and Recognitions:Other: 2009 Georgia Gold Medal Winner 2010 Great Plant Picks award winner 2011 Perennial Plant of the Year 2012 Oklahoma Proven! plant selection

2011 PPA Plant of the year.
Native to the Ouachita Mountains in Arkansas.
MOBOT rates plant at 5 stars.

Threadleaf Blue Star has very narrow needle-like leaves 3 to 4 inches long and only a matchstick in width giving it a fine, brushy look. The plant grows approximately 3-4 ft. tall here. The flowers are a medium dark steel blue in late spring. It prefers a dry-ish site.

Fall color is a good deep gold before the plants die back for the winter. This is a very attractive and dependable plant. Plus, it is deer-resistant.

Mine has never turned this brilliant yellow/orange in the fall. It's in full sun. Not sure why.

For best results (if planting more than one of these plants), space them at least 1 and a half feet apart from each other.
Landscape uses:
Plant bluestars singly or in small groups in the middle of a border. Willow amsonia does well in damp soil and is a good choice for planting by the side of a stream or pool.

How to Grow Bluestar Amsonia

Generally, Amsonia prefers full sun or light to partial shade, Gardening Know How elucidates. Amsonia species prefer moisture but not too much of it. Choose a spot in your garden with full sun if your soil is less well-draining. Planting Amsonia in too much shade may cause the plant to spread as it grows or to flop open instead of growing into a neat mound. You can also deadhead Amsonia after flowering to prevent self-seeding and to keep the stems from flopping over due to the weight of developing seed pods.

Once your Amsonia is planted, do not allow the soil to dry out. Water Amsonia slowly and deeply when the soil surface feels dry to the touch so that the plant can absorb as much water as possible without becoming soggy. A thick layer of organic mulch will help Amsonia species grow, and Amsonia should not be watered regularly in the fall.

Amsonia Growing Conditions - How To Care For Amsonia Blue Star Plants - garden

Blue Ice Star Flower flowers

Blue Ice Star Flower flowers

Blue Ice Star Flower in bloom

Blue Ice Star Flower in bloom

This variety is more compact than the species with deeper blue flowers lovely along borders or edges an impressive statement in blue when massed

Growing Place Choice Plants

Our Growing Place Choice plants are chosen because they are strong performers year after year, staying attractive with less maintenance when planted in the right place.

Blue Ice Star Flower has blue star-shaped flowers at the ends of the stems from late spring to early summer, which are interesting on close inspection. The flowers are excellent for cutting. Its narrow leaves are light green in color. As an added bonus, the foliage turns a gorgeous yellow in the fall. The fruit is not ornamentally significant.

Blue Ice Star Flower is an herbaceous perennial with a more or less rounded form. Its medium texture blends into the garden, but can always be balanced by a couple of finer or coarser plants for an effective composition.

This is a relatively low maintenance plant, and should be cut back in late fall in preparation for winter. Deer don't particularly care for this plant and will usually leave it alone in favor of tastier treats. It has no significant negative characteristics.

Blue Ice Star Flower is recommended for the following landscape applications

  • General Garden Use
  • Naturalizing And Woodland Gardens

Blue Ice Star Flower will grow to be about 12 inches tall at maturity, with a spread of 24 inches. It grows at a slow rate, and under ideal conditions can be expected to live for approximately 20 years.

This plant does best in full sun to partial shade. It prefers to grow in average to moist conditions, and shouldn't be allowed to dry out. It is not particular as to soil type or pH. It is quite intolerant of urban pollution, therefore inner city or urban streetside plantings are best avoided. This is a selection of a native North American species. It can be propagated by cuttings however, as a cultivated variety, be aware that it may be subject to certain restrictions or prohibitions on propagation.

Amsonia tabernaemontana can be found growing in floodplain forests and on the slopes of rich forests throughout southern and central United States.

Plants are propagated by cuttings. Our stock plants were grown from seeds collected on a streambank in Pender County, NC.

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You can use Bluestar artistically to create colour contrast and back drops in an ornamental garden. It works exceedingly well when used to border path ways, or in the transition between the bright and shaded spots in your garden.

They can be used as a back drop for the colors of more exotically colored plants, especially the silvers and blues of Scabiosa and Artemisia.

Another nice idea is to plant Blue Star alongside perennials with dark leaves, such as Heuchera and Sedum, where the gold colors of the plant in fall will create a lovely contrast.