Sunday, July 3, 2011

Tetraploid-à-Tet: What does tetraploid Daylily really mean?

Hemerocallis 'Prime Minister'

It is the peak of Daylily (Hemerocallis) season here in Central Illinois and companies are pushing everything from their newest "Tet" selections to the old fashioned Daylilies. But what does this name Tet or Tetraploid Daylily mean and why are they saying it is better?

What does tetraploid daylily mean?
I looked around at Daylily websites to find what they had to say about definition of tetraploid and frequently found them to be circular. Using the word to define the word.

Tetrapoidy in lilies means that two nuclei have been fused together doubling the number of chromosomes normally found in a cell creating two sets of chromosomes. This doubling creates more genetic mutations (outcomes) available for creating new plants.

Why do they say it is better?
The mutations that occur from the doubling of chromosomes results in the ability to breed new plants that have more admirable traits, such as flower color, stem thickness, leaf shape or plant habit. The breeding possibilities are much greater. Flower color is usually more intense and there are far more options available than the reds, oranges and yellows that are available in the diploids friends.

Hemerocallis 'On and On'

What else?
There are some other traits that are often found in tetraploid Daylilies. They don't spread or divide as rapidly. This could mean there won't be the same ground cover effect as with Hemerocallis fulva or other diploid varieties. On the flip side you don't have to dig and divide your plants nearly as frequently or work to keep them in check. Another change is that there also tends to be fewer flowers per scape (stem) as their diploid friends. While we are on the topic of friends, tetraploid and diploid flowers don't cross to produce viable seeds. They must remain friends in the garden.

  1. American Hemerocallis Society 
  2. Down to Earth Garden Club 
  3. Wikipedia


  1. I'm a big daylily fan. Thanks for this information. Love your photos!

  2. Thanks for the feedback Jennifer. I love Daylilies. I also love water gardens :)


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