Plant Profile: Helianthus debilis, Beach Sunflower

By Kelsey Olsen and Stephanie Shankle


This post is one of a series from professor Nisse Goldberg's Botany students at Jacksonville University. 


Figure 1. Helianthus debilis, note heart-shaped leaves
and yellow ray flowers with red-brown disc flowers.
Photo credit: Shirley Denton.
Going to catch some waves? If you're lucky, you'll see some beach sunflower, Helianthus debilis, also known as east coast dune sunflower. This Florida native and member of the aster family (Asteraceae) can be found on beaches and in dunes along the east coast and has been introduced up the coast to North Carolina. As its common names suggest, it can survive in dunes where it may be exposed to salt spray and salty soils. Despite its fondness for waterfront areas, Helianthus debilis does not do well in flooded areas.

Two subspecies also occur in the state. One of these, H. debilis ssp. cucumerifolius (cucumberleaf dune sunflower), is common in Florida's central and western counties, while the other,  H. debilis ssp. vestitus (west coast dune sunflower), is endemic, and found in six counties (from Pinellas south to Lee) along the west coast of the state.

You can recognize the plant by its heart shaped leaves and spreading growth pattern (Figure 1). Its inflorescence is a head (typical of the Asteraceaes) with two types of flowers: yellow ray flowers and reddish-brown disk flowers (Figure 1). H. debilis produces achenes, a dry fruit, and blooms year-round..

This plant plays an important role in beach conservation, used for dune stabilization, wind erosion protection, and beach beautification efforts. It also serves as a source of nectar for butterflies and bees, and its fruits are eaten by birds and other animals found in the dune habitat.

Interested in growing your own? Beach sunflower does best in full sun. Not surprisingly, they are drought-tolerant and grow well in sandy-soils. Vendors that sell the plant can be found using this link from the Florida Association of Native Nurseries: http://www.floridanativenurseries.org/plants/detail/helianthus-debilis-subsp-debilis.


References

Image source

Comments

daisy g said…
I really would like to try growing this as a groundcover in my backyard bed. Would it do well on a trellis?
May 31, 2012 at 1:32 PM
Florida Native Plant Society said…
Also see an earlier post we did on this great native groundcover. http://fnpsblog.blogspot.com/2010/11/east-coast-dune-sunflower-appreciation.html
May 31, 2012 at 2:08 PM
Florida Native Plant Society said…
Hi Daisy. I'm a bit confused with your question, since trellises are typically used for training vines onto. It is an excellent groundcover. I have never seen it grown on a trellis, and I imagine it would be quite a bit of work to make that happen, since it does not have a twining or climbing habit, nor does it have tendrils. You would have to tie it onto your trellis to get it to stay put. Best to allow it to spread horizontally. Thanks for your interest!
May 31, 2012 at 6:31 PM
Vital1 said…
Mine has died out in the front yard, which is dry in the winter (no irrigation and little rain), but rather wet with all the rain we've been having... Or is there a particular disease that could affect it?
June 2, 2012 at 7:32 AM
Vital1 said…
Mine has died out in the front yard (West Palm Beach)... it is dry in the winter, with no irrigation and little rain, but wetter now with all our rain... Or is there a disease that could be affecting it? Thanks!
June 2, 2012 at 7:34 AM
Florida Native Plant Society said…
Hey there! Thanks for asking. I imagine it is both - a disease CAUSED by all of the rain. Without seeing yours I can't be certain which, but H. debilis can get the following leaf and stem diseases: Alternaria sp.; Anthracnose; Botrytis sp., powdery mildew and Pythium root rot.
June 3, 2012 at 10:03 PM
Anonymous said…
How much ground does one plant cover?
September 12, 2013 at 3:01 PM
Florida Native Plant Society said…
It will cover about 4 square feet.
September 13, 2013 at 5:54 PM
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