Helianthus angustifolius: Swamp Sunflower

Swamp SunflowersLatin name: Helianthus angustifolius
Common name: Swamp Sunflower
Flowers: 2-3” yellow daisy-like flowers that bloom late summer – fall13,4
Fruit: Small achene in the fall13
Height & Width: 5-8’ x 2-4’13
Type: Herbaceous perennial10
Habit: Upright13
Wetland indicator category**: FACW, FAC17
Texture: Medium13
Growth rate: Medium13
Light: Full sun to part shade10,13
Moisture: Medium10
Soil*: Wet acidic sandy – clay loam13
Zones: 5-913
Origin: L4816
Ecosystem benefits: It attracts and feeds birds and many insects including native bees10

Features: This plant produce many bright yellow flowers in the late summer that persist into the fall when other plants may not be blooming13. It also attracts several species of bird and insect10. It can be planted along streams or ponds and does well in pollinator or naturalized gardens13.

Siting: Swamp sunflower should be planted in moist to wet soil in full sun to part shade10. Since it can get up to 8 feet tall, it should be planted in the back of a garden with room to grow13.

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.

Pests: Plants are relatively pest resistant if cultural preferences are met.

This plant does not appear on the following invasive plant lists on 2/24/2020:
USDA SC Invasive Plant Species
SC Exotic Plant Pest Council

Author: Kerrie McCaffrey

Image source: http://southeastgarden.com/helianthus.html


  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 Georgia.
  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

*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

Plant Wetland Indicator categories
Indicator Code Indicator Status Comment
OBL Obligate Wetland Almost always is a hydrophyte, rarely in uplands
FACW Facultative Wetland Usually is a hydrophyte but occasionally found in uplands
FAC Facultative Commonly occurs as either a hydrophyte or non-hydrophyte
FACU Facultative Upland Occasionally is a hydrophyte but usually occurs in uplands
UPL Obligate Upland Rarely is a hydrophyte, almost always in uplands