Amsonia tabernaemontana: Eastern Blue Star

Courtesy George H. Bruso, Lady Bird Johnson Wildflower Center

Latin name: Amsonia tabernaemontana
Common name: Eastern Bluestar, Blue Dogbane
Flowers: ¾”, delicate blue star-like flowers¹² in March, April, and May¹⁰
Fruit: Tan, slender follicles containing corky, cinnamon-brown seeds¹⁰
Height & Width: 1-3 feet tall and wide¹⁰
Type: Herbaceous perennial¹²
Habit: Erect, clump-forming¹²
Wetland indicator category**: FACW (Facultative Wetland) in the Atlantic and Gulf Coastal Plains region and FAC (Facultative) in the Eastern Mountain Piedmont region¹⁰
Texture: Fine²⁰
Growth rate: Medium³
Light: Full sun to part shade¹²
Moisture: Medium¹²; drought tolerant¹²
Soil*: Tolerate clay soils, but prefers well-drained, moist, loamy soils¹²
Zones: 3-9¹²
Origin: Eastern United States; Maryland south to Florida, southwest to Texas and northwest to Illinois¹⁰

Features: These plants are primarily grown for the delicate blue flowers that give them their common name¹². They also produce a toxic latex when the stem is cut or damaged, making them resistant to damage by deer and most pests¹⁵. The foliage may also turn a pleasant yellow in the fall¹².

Siting: Can perform quite well in a rain garden, and tolerate drought once established¹². The flowers also make nice cut flowers¹². Often grown in masses in informal settings, these may also be used in borders or containers¹².

Care: Plant crown at soil level¹⁸. At planting, water the roots and surrounding area slowly and deeply. Keep soil moist until plant is established, then apply enough water to thoroughly moisten the root zone when the soil is dry or during drought. Modify water recommendations to reflect site drainage and rainfall. Apply 3” of mulch over the planted area. Do not allow mulch to touch the plant stems¹⁸. When grown in shade or nutrient-rich soils, may require staking or pruning¹². If pruning, it is recommended to cut the stems back ½ to 1/3 after flowering to promote bushy growth and a more rounded habit¹². Seeds are produced in the fall which may be used for propagation¹³.

Pests: Plants are relatively pest resistant if cultural preferences are met¹⁵. This species is susceptible to Coleosporium apocynaceae in the Southeastern United States.

This plant does not appear on the following invasive plant lists on 11/26/19:
USDA SC Invasive Plant Species
SC Exotic Plant Pest Council

Author: Angelica Werth

Image source: https://www.wildflower.org/plants/result.php?id_plant=AMTA2

Sources:

1. Armitage, A. (2001). Armitage’s manual of annuals, biennials, and half-hardy perennials. Portland, OR: Timber Press.
2. Armitage, A. (2006). Armitage’s native plants for North American gardens. Portland, Oregon: Timber Press.
3. Armitage, A. (2008). Herbaceous perennial plants: A treatise on their identification, culture, and garden attributes. Athens, GA: University of Geogia.
4. Clemson Cooperative Extension Home and Garden Information Center.(2011). Flowers fact sheets. Retrieved from https://hgic.clemson.edu/category/flowers/
5. Clemson Cooperative Extension Home and Garden Information Center.(2011). Groundcovers & vines fact sheets. Retrieved from https://hgic.clemson.edu/category/groundcovers/
6. Clemson Cooperative Extension Home and Garden Information Center.(2011). Trees. Retrieved from https://hgic.clemson.edu/category/trees/
7. Clemson Cooperative Extension Home and Garden Information Center.(2011). Shrubs. Retrieved from https://hgic.clemson.edu/category/shrubs/
8. Dirr, M. A. (2009). Manual of woody landscape plants. Champaign, IL: Stipes Publishing.
9. Gilman, E. F. (1997). Trees for urban and suburban landscapes. Albany, NY: Delmar Publishers.
10. Lady Bird Johnson Wildflower Center University of Texas at Austin. (2012). Native plant information network. Retrieved from http://www.wildflower.org/explore/
11. McMillan, P., Plant taxonomist Clemson University, personal communication.
12. Missouri Botanical Garden Kemper Center for Home Gardening. Plant finder. Retrieved from http://www.mobot.org/gardeninghelp/plantfinder/Alpha.asp
13. North Carolina State University (2005). Plant fact sheets. Retrieved from http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/index.html
14. Strother, E. V., Ham, D. L., Gilland, L. (2003) Urban tree species guide: Choosing the right tree for the right place.  Columbia, SC: South Carolina Forestry Commission.
15. University of Florida, IFAS Extension. (2011). Southern trees fact sheet. Retrieved from http://edis.ifas.ufl.edu/department_envhort-trees
16. USDA. Plant profile. (n/d).Retrieved from http://plants.usda.gov/java/
17. USDA. Plant wetland indicator status. (n/d). Retrieved from http://plants.usda.gov/wetland.html
18. Vincent, E., Environmental horticulturist Clemson University, personal communication.
19. Clemson Extension. Carolina Yards Plant Database. Retrieved from https://www.clemson.edu/extension/carolinayards/plant-database/index.htm
20. Mahr, S., University of Wisconsin-Madison Master Gardener Program. Division of Extension Articles. Retrieved from https://wimastergardener.org/article/willowleaf-bluestar-amsonia-tabernaemontana/

*Soil pH is determined using a professional soil test. Contact your Clemson University County Extension service for assistance www.clemson.edu/extension/. Click on “local offices”.

**2012 Plant Wetland Indicator categories (quantitative derived) http://plants.usda.gov/wetinfo.html