Butterflies on Broom

American snout butterfly on desert broom, Box Bar Recreation Area, Arizona, 23 Oct 2021 (photo by Kate St. John)

30 October 2021

While visiting Arizona I noticed that one plant in particular attracted lots of butterflies. The plant above was covered in snouts (Libytheana carinenta) though only one shows up in my photo.

Eventually I learned that the plant is desert broom (Baccharis sarothroides), a dioecious shrub with very different male and female flowers (male on left, female on right below). The male flowers get all the attention from butterflies.

Male and female flowers on desert broom, Box Bar Recreation Area, Tonto National Forest, 23 Oct 2021 (photo by Kate St. John)

It’s hard to imagine how the female flowers become pollinated when nothing seems to visit them.

Next month after the flowers are fertilized the seeds will be ready to disperse. I’m sorry I’ll miss the period when the brooms look fluffy.

(photos by Kate St. John)

4 thoughts on “Butterflies on Broom

  1. I was in Arizona last month, and was astounded at the amazing amounts of butterflies the desert harbors. Unfortunately large quantities were being killed flying across I-10 and other roadways. But it was delightful observing them while hiking in the desert.

  2. I try to keep desert broom from growing in my yard, but allow it to bloom around the periphery. Due to Tucson’s unusually wet monsoon this year (after a record dry one in 2020), we have hundreds of butterflies in our yard. I have observed at least 15 species of butterflies nectaring on the desert broom, in addition to various bees and wasps.

  3. My Southwest garden is full of desert broom–all volunteers! I leave them because the female flowers smell so delicious (like maple syrup) and because the puffs from the male flowers are so much fun! The female flowers are loaded with bees–I’ve had over 100 bees on a single shrub this autumn! Butterflies (snouts, emperors, viceroys, queens, and also various skippers) also visit the male and female flowers. The female flowers tend to finish blooming just as the male flowers begin to bloom.

  4. oops! I just realized I got that backwards! It’s the male flowers that smell like maple syrup and the females that have the puffs! So the male flowers finish blooming right before the female flowers bloom.

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