UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail:  dfculbert@ifas.ufl.edu

Quick Links:   Short Day flowering   Pinebarren Goldenrod Southeastern Sunflower References    

October 19, 2005

Feature Article - for release the week of October 23, 2005

Dan Culbert - Extension Horticulture Agent

 Falling for Yellow Wildflowers.

As I’m writing this column a week before the storm, I’m wondering if Wilma will have left much natural beauty in her wake for us to see.  Along the roads in our area, I’ve noticed that fall has arrived in the form of several wildflowers.  So to give us a little rest from all those weighty cleanup chores, please be safe and enjoy the visual bouquet as you travel our beautiful countryside.

Wildflowers are seasonal in nature, and gardeners sometimes wonder why certain flowers appear during certain times of the year.  So, in addition to introducing a pair of these yellow beauties, this column will describe how Mother Nature knows when to lay a yellow blanket over our fields and forests in the fall.

Timing is everything, as this is a matter of survival with many flowers.  For seeds to grow, and plants to rest, they must time their flowers perfectly with the right amount of moisture, temperature and humidity for survival. In the fall, a number of plants have internal mechanisms that get them to flower as days are getting shorter and temperatures are getting cooler.

The response to flowering in the fall is shown by plants that are called short day plants.  But a look at how they do this would better call them long night plants. 

Among the many chemical processes going on in plants, a pigment is changed from one form to another during the day.  At night, the process is reversed.  The relative amount of this “phytochome pigment” signals the rest of the plant either grow more leaves, or start to form flowers which will led to seed.

In the fall, long night plants form flowers when the days become longer than the nights. This change occurs every year, hot or cold, hurricanes or not, and the result will be a blanket of flowers year after year.

Among fall markers in our area, besides pumpkin vendors and football games, is a medium to tall upright plant that has drooping yellow clusters of small yellow flowers.  These plants are known as Goldenrod, and as best as I can tell,  as many as six different species are found in south central Florida.  Statewide, there are 21 species of Solidago, the Goldenrods, and about 70 different Goldenrods are found in the Eastern US.  Some are endangered; many are found growing only in certain kinds of habitats, while others have a wide range.  And their pollen does not cause hay fever. 

Pinebarren Goldenrod, Solidago fistulosa   Photos by Dan Culbert, UF/IFAS

One of the most common Goldenrods in our area is the Pinebarren Goldenrod, S. fistulosa.  It’s common name may suggest that it is found in pine forests, but it is quite adaptable to any sandy, moist soil – which are very common in our area.  They grow from 2 to 6 feet tall, and are topped with plume-like clusters of golden yellow flowers that arch over.  Look closely and you will see an abundance of insects on the small flowers. 

A second fall flower that is quite striking is a member of the Sunflower family.  Most people have a pretty good idea of what a sunflower looks like, but the sunflowers now painting our roadsides yellow are generally daisies.  And in fact, both the sunflowers and goldenrods are part of the large plant family called the Composite or Daisy family.

Southeastern Sunflower (Helianthus agrestis Photo by Dan Culbert, UF/IFAS

My sources tell me that there are as many as 21 sunflower species in Florida, and hundreds across the US.   But only one species, the Southeastern Sunflower (Helianthus agrestis) forms such dramatic patches of tall flowering daisies in our area of Florida.  This beautiful plant grows unnoticed in wet roadside areas through the spring and summer, but erupts into a branched head of 20 to 40 yellow daises.  In the middle of the yellow petals is a tight cluster of purplish brown true florets.  Sometimes they have small touches of yellow hidden in their flower head.    

Insects will pollinate both these flowers, and the petals fade and leave bumps of seed capsules.  Tiny seed fall in place or are blown to another area, where they can lead to a new colony of these fall wildflowers.  The mother plant will die back, fall to the ground, and will rest until spring when they resprout and the cycle begins again.

I’ve placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.  If you need additional information on wildflowers, please email us at okeechobee@ifas.ufl.edu or call us at 863-763-6469.  Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners on Tuesday afternoons from 1 to 5 PM.  


Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.  Florida Cooperative Extension Service / IFAS / University of Florida.  Larry A.  Arrington, Dean Last update: 10/19/2005 .  This page is maintained by Dan Culbert  Hit Counter


Atlas of Florida Vascular Plants http://www.plantatlas.usf.edu/