Common Name(s):Blue Star or Bluestar - Different species have many common names. (See below.)
Amsonia species were given the common name "Blue Star" for their soft blue, star-shaped flowers. The individual flowers are small, but they bloom in fluffy clusters and put on a lovely show for several weeks.
Amsonia flowers are one of the truest blues you will find in flower colors. The plants are native to many regions of North America and grow pretty much problem free. The airy, but substantial, texture of the foliage provides a great foil for almost any other plant, making them very versatile in garden design. A bonus is the brilliant yellow fall foliage.
Leaves: 3-4 inch, narrow, lance-shaped leaves with a pronounced mid-rib.
Flowers: Clusters of small, star-shaped blue flowers, borne on top of tall stems.
Hardiness will vary with species. Most are at least USDA Hardiness Zones 5 - 11. Amsonia tabernaemontana can be hardy down to USDA Zone 3.
Full sun to Partial Shade.
24 - 36" (h) x 24 - 36"(w)
Bloom Period:Late Spring - Early Summer
The soft, billowy foliage of Amsonia allows it to fit in most anywhere. Although it can reach 3 feet tall, it is still nice along a walkway, where it moves with you. It also pairs especially well with larger leaved plants, like peonies and hosta. A personal favorite combination is Amsonia paired with the seed heads of oat grass.
- Arkansas Amsonia, Hubricht's Blue Star, Narrow Leaf Blue Star (Amsonia hubrichtii) - Narrow, needle-like leaves and bright blue flowers.
- Ozark Bluestar (Amsonia illustris) - Taller plant (4 ft.) with glossy leaves and larger flowers.
- Blue Dogbane, Eastern Bluestar, Willow Amsonia, Woodland Blue Star (Amsonia tabernaemontana) - Wider leaves and pale blue flowers.
Soil: Amsonia likes a neutral soil pH, between 6.2 and 7.0, but will grow just about anywhere, even in poor soil. It does not like prolonged dry conditions, but once established, Amsonia plants can handle brief periods of drought.
Amsonia can be grown from seeds harvested when the pods dry. You can start seeds in the fall and over-winter them in a cold frame or protected area, then transplant in the spring. Simply cover them lightly with soil and keep the soil moist, until the plants germinate.
Amsonia plants are becoming more commonly available in garden centers and develop into good sized plants within 2 - 3 years.
Maintenance:Amsonia requires very little maintenance. They can get floppy when they are heavy with flowers and when the seed pods form. To prevent this, you can either stake them with a hoop or trim them back by one third, after flowering. Trimming will mean losing the attractive seed pods. Since deadheading is not necessary, framing your Amsonia with sturdy plants on either side is a third choice for helping to support the plants and keep them upright.
The plants will bush out and get wide, up to a couple of feet across, but they do not spread or travel very far or become a nuisance. You can divide the plants, if you want to make more plants, but it is rarely necessary.
Pests & Problems:Amsonia plants are virtually problem free. No pests are diseases regularly bother them.
More on adding blue flowers to your garden.