Irises: Bearded Iris Experiment Completed!, 1 by BlissfulGarden

BlissfulGarden wrote:
Some of you may remember me from when I began an experiment to grow bearded iris in the Deep South. The first year has passed, so I am sharing my results here. Gardening sense in the most humid and hot parts of the Deep South typically tells us that bearded iris will not grow and thrive here. However, for many years, I have yearned to grow beardeds in memory of my grandfather from Kansas. I decided to test the garden sense in a full-scale experiment. I began by soliciting advice on planting, disease control, pest control and potential cultivars from growers, hybridizers, and avid gardeners on DG and other gardening sites. Of exceptional help was Mr. Walter Moores, a hybridizer who currently resides in the Deep South. I was looking for the hardiest cultivars, as well as the cultivars that were hybridized in closest proximity to my locale (Baton Rouge, Louisiana). My experiment was to investigate four questions:

(1) Would any bearded iris cultivars thrive in Baton Rouge, Louisiana?
(2) Would rebloomers, which require more moisture than non-rebloomers, tolerate our humid conditions better?
(3) Would cultivars that were hybridized in the deep south have a better survival rate than those that were hybridized in cooler regions?
(4) Would the size of the rhizome at planting make a difference in the survival rate?

I began with 217 cultivars, including 200 that I had specifically ordered and another 17 that arrived as bonus rhizomes with my various orders. I planted them and cared for them per the wonderful advice I had received from those irisarians I consulted. (If you are interested in the specific growing culture I used, you can find all of that information posted on http://www.eveysblissfulgarden.com)

As the year progressed, these plants endured two hurricanes, two extremely unusual droughts (one in winter and one in late spring), digging and chewing by squirrels and dogs, 100+ degree days coupled with upper 80's at night, and finally our typical Louisiana weather of high humidity with daily rains. Some cultivars were removed from the experiment due to failure to thrive (yellowing foliage, no growth or multiplication in the plant, etc.). Some cultivars were removed from the experiment when they showed signs of rot, despite regular preventive applications of Terrachlor/PCNB. The plants were free of pests for the year, which is quite unusual for plants here in Louisiana. They also did not show any signs of disease other than rhizome rot or slight nutrient deficiency. I had been cautioned against using nitrogen with the rhizomes in our region, so it took a while for me to get the nutrition correct! Here is a summary of the results.

(1) Of the 217 cultivars tested, 73 cultivars survived their first year here with acceptable growth and healthy foliage.
(2) Contrary to what I had assumed, rebloomers did not exhibit a better survival rate.
(3) Those cultivars that were hybridized in hot and humid locations did, in fact, exhibit a better survival rate. In particular, those cultivars by Walter Moores (from Texas and later Mississippi) and by Tom Burseen (from Texas) showed great promise. Unfortunately, the cultivars by Bernice Miller (from Alabama) did not exhibit a better survival rate than those that came from Northern or West Coast hybridizers.
(4) The size of the rhizome at planting did not seem to make a difference in survival rate. For quite a few cultivars, I purchased large rhizomes from West Coast growers and small rhizomes from Northern and Texas growers (of the same cultivar). If a cultivar survived, it appeared to be consistent... both the large and the small rhizomes made it through the year. If a cultivar died, it again appeared consistent... both large and small rhizomes rotted or declined.

And finally, here are links to the lists of cultivars that I included in the experiment:

Cultivars that survived the first year here in Baton Rouge - http://davesgarden.com/tools/journal/viewbycat.php?catsort=n...

Cultivars that declined or rotted during the first year here in Baton Rouge - http://davesgarden.com/tools/journal/viewbycat.php?catsort=n...

I will continue growing 25 of the cultivars from this point on and have sent the others to friends.

THANKS SO MUCH to all of you who helped me with advice and encouragement as I began and conducted this experiment. I am truly grateful! Ev =)

This message was edited Jul 29, 2009 2:07 AM