Chapman’s Blazing Star…Lovely Autumn Wildflower (in May?)

06 May

Liatris chapmanii

(The origin of “Liatris” is not known, perhaps a very old name.  Alvin Chapman was a physician and seminal Florida botanist.)


Something’s odd in the Delaware Scrub Natural Area in Jupiter.   Driving by yesterday, what is that tall purple wildflower in the scrubby sand?    Stop, go back and check it out—well, how weird, it is Chapman’s Blazing Star.   Liatris chapmanii, which always blooms late summer and autumn, is in full bloom across one corner of the natural area.   How can that be?   It is one of the earlier-flowering Liatris species,  August-October, but May is absurd.

Chapman’s Blazing Star, yesterday May 5, 2022

The main reason many autumn flowers bloom in the harvest months is a response to the lengthening nights after the June 21 summer solstice, the daylength cue sometimes interacting with temperature.   If the long night is interrupted with artificial light it can throw off the plant’s internal clock.  When horticulturists deliberately break up long nights with artificial light to manipulate flowering, turning on the lights  is called a  “NI” (night interruption).  Researchers Ignacio Espinosa and Will Healy in Maryland, interested in commercial year-round Liatris (L. spicata) production as a cut flower, applied different combinations of temperatures and NI’s to influence the Liatris flowering season in varied ways.  Our L. chapmanii is more “tropical” so its temperature-related behavior would differ from more-northern L. spicata.

All that being so, what triggered flowering in Chapman’s Blazing Star 6 months out of sync?   Looking around the site of the funny flowering, there is “NI” on a pole…a street light (actually two of them) beaming directly onto the Liatris patch.  Wonder if anything else there flowers at the wrong time.


Posted by on May 6, 2022 in Uncategorized


6 responses to “Chapman’s Blazing Star…Lovely Autumn Wildflower (in May?)

  1. theshrubqueen

    May 6, 2022 at 5:01 pm

    Aha! urbanish light pollution!?

    • George Rogers

      May 8, 2022 at 10:56 am

      True, but then again, Indiantown Rd. is no pristine habitat! And Delaware Scrub is known to have lurkers lurking (actually have had a shady encounter walking at that very corner), so if I pass by on the sidewalk, a little light may be welcome along with the unseasonal floral treat.

  2. Laure Hristov

    May 6, 2022 at 5:43 pm

    Wow, that is a pretty one so glad it’s blooming even before it’s time! Interesting how the lighting can have such an influence on the plants blooming cycle. Talk soon!



    • George Rogers

      May 8, 2022 at 10:56 am

      Totally so on all points.

  3. Harvey Bernstein

    May 9, 2022 at 11:40 am

    Ah light (and sound) pollution, the least considered of developmental and environmental issues!

    • George Rogers

      May 13, 2022 at 7:04 pm

      so true….and you really notice it on those rare occasions where you escape both


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