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)

2 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.

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