I know planting tropical milkweed has been controversial with numerous scientific studies against it due to possibility of messing up migration and the issue with OE parasite. Many of the large monarch conservation orgs like Xerces are completely against it but others also claim that it has medicinal effects for the infected monarchs...
I visited a local conservation area and they plant all types of milkweeds. They have found that the monarchs prefer the tropical milkweed over the native ones. I read online that the residential monarchs or ones that breed year round, need the tropical milkweed, but I have also read online that winter-breeding is harmful for the migratory monarchs so we should just stick to natives...
We are starting to build our school garden and have been adamant about strictly planting only natives so it is unlikely that we will plant tropical milkweed, but I would love to know if anybody has arguments for the planting of tropical milkweed, especially in our situation.
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Wesley Chen
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