Can you tell me if balloon plant (Gomphocarpus physocarpus) is helpful for monarch caterpillars?

Answer

Gomphocarpus physocarpus (syn. Asclepias physocarpus), or balloon plant, is a non-native, tropical milkweed. While native milkweeds are a good nectar source and larval host for monarchs, tropical milkweeds may not be helpful for monarch caterpillars. A fast growing annual in the New York City region, balloon flower can sustain lots of monarch caterpillars late in the season when there may not be much else available. But its presence can also confuse butterflies into breeding at a time when they should be migrating. In regions where this tropical milkweed doesn't die back in the winter, it can also become a host to a parasite that is dangerous to monarch caterpillars.

For more information on plants that do benefit butterflies from our library guides, Butterfly Gardens.

For some helpful information on these and other problems for monarchs associated with tropical milkweeds, read this excellent article from Xerces Society for Invertebrate Conservation.

Courtesy of NYBG Plant Information Service

  • Last Updated Feb 19, 2021
  • Views 519
  • Answered By Anita Finkle

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