Seedling displaying early blooms - Ask Extension
I have been growing Mexican Sun Flowers from seeds for almost 5 years. I grow the tall variety that gets 4-6' tall. But this year's crop did someth...
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Seedling displaying early blooms #757825
Asked June 22, 2021, 8:35 PM EDT
I have been growing Mexican Sun Flowers from seeds for almost 5 years. I grow the tall variety that gets 4-6' tall. But this year's crop did something very unusual. They got to a little over 1 foot tall and started blooming. That has never happened before. They usually start blooming when they get 3-4' tall. It made the recipients of my plants think that I had given them the shorter variety of Mexican Sun Flowers.
Temperatures in May were cool and cloudy but June turned into sunny and very hot days. Could the short transition from cool to very hot have been the cause of early flowers on short plants? Do you know why I got flowers on short plants?
Hennepin County Minnesota
Expert Response
I think you are correct. Some flowering plants are affected negatively by heat (less flowers, dieback sooner) and others bloom earlier in response to higher temperatures earlier. The dramatic change in temperatures could have pushed the Tithonia into blooming quickly before the plants actually grew to their mature size. Knowing Tithonia, this plant will like continue to grow and bloom throughout the summer into early fall.
Here is an interesting interview with Jake Weltzin of the U.S. Phenology Network on NPR about phenology and climate effects on plants and animals.
https://www.npr.org/2012/03/15/148698272/whats-the-impact-of-early-blooms
