Where Have All The Flowers Gone

Image of giant blue irises with trees in the background
The springtime blooms of giant blue irises once drew thousands of visitors to the Barataria Preserve each year. A changing landscape has reduced the number of flowers---what happened?
White spider lilies in bloom at the Barataria Preserve
Spider lilies are part of nature's annual spring wildflower show at the Barataria Preserve

Giant blue iris update: More giant blue irises were in bloom in spring 2014 than have been seen in years and 2015 was also a very good year---fingers crossed that it's a trend for the future!

There is a springtime ritual at the Barataria Preserve every year, probably since the Bayou Coquille Trail was first opened as a shell-and-dirt path through the swamp. People call the visitor center and ask, "Are the irises in bloom yet?"

For years, a springtime walk along the Bayou Coquille Trail meant a spectacular show of giant blue irises in bloom. In recent years, only a few giant blue irises could be seen along the Palmetto, Visitor Center, and Bayou Coquille Trails. Where have all the irises gone?

The last impressive bloom of giant blue irises was in 2002. That September, Hurricane Lili briefly filled the preserve with several feet of brackish water. Irises are sensitive to salt water, which retards flowering or even kills the plants.

Spring 2003 saw a great reduction in iris blooms. Although the springs of 2004 and 2005 encouraged some optimism that the fields of blossoms would eventually return, 2005's hurricanes seem to have caused another setback for the irises along the Bayou Coquille Trail.

Hurricane Katrina destroyed thousands of trees at the preserve and opened the tree canopy, the overhanging leaves and branches that keep the floor of the swamp shaded. As a result, more sunlight poured into the swamp, encouraging the growth of many species of plants in places where they would not have thrived before the storm, including places where irises grew.

Like Hurricane Lili, Katrina and Rita filled the preserve with several feet of brackish water. Although the water drained away in a few days, the effect of the water and decreased oxygen levels in the soil may have damaged the delicate irises. The residual salt left in the swamp may have damaged them even more. For months after Rita there was no significant rain and so salt from the brackish water was not flushed out.

Other plants began to grow where the irises once thrived. Native species such as pennywort (dollar weed) and marsh fern as well as invasive, non-native species such as alligator weed filled the swamp, crowding and stressing irises that may have survived. The great numbers of giant blue irises that once bordered the Bayou Coquille Trail disappeared.

Whether they will ever return in their previous numbers cannot be predicted. Giant blue irises are thriving elsewhere in the preserve, and every year a few more are seen growing along the trails.

Ecology is an inexact science, with so many variables that precise predictions are very difficult. No formal scientific studies have been done to determine why the fields of irises have not returned to the Bayou Coquille Trail. Was it the salt water? Disease? The new plants growing in iris territory? What is known is that several hits by hurricanes certainly stressed the irises.

On the other hand, many wildflowers have flourished in recent years, including narrow-leaf vetch, spider lilies, dewberries, and red/copper irises. The giant blue irises seen today offers hope that one day preserve visitors will again enjoy fields of blooming blue.

To find out more about giant blue irises, click here. Plant lists for the preserve are available here.

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Mailing Address:

419 Decatur St
New Orleans, LA 70130


(504) 589-3882
Phone numbers are for park headquarters. Phones are answered 8:00 a.m.-4:30 p.m. Monday-Friday. Park headquarters is closed on federal holidays and on Mardi Gras.

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