Annuals are great for drawing butterflies up-close — place groups of pots of varying sizes on your porch, deck or patio. The more the better for catching the eye of passing butterflies. Keep in mind that some plants (petunias, for example) may also be used by butterflies as hosts for their caterpillars, which will do some damage. However, if your goal is to attract butterflies, you’ll have to refrain from using insecticides.
It would be easy if we could just move caterpillars from a desirable plant to a less desirable one. But, caterpillars are finicky about what they’ll eat — they’ll starve to death rather than feed on an unsuitable plant. For example, moving a Black Swallowtail Butterfly caterpillar from, say, a parsley plant to a phlox will kill it. They must be moved to the same kind of plant. That would seem to leave only two choices: Tolerate damage to precious plants or remove the caterpillars, in which case they’ll die. But, we recommend a third alternative: Plant a duplicate pot or two of the precious plants you know will attract caterpillars. When caterpillars show up on them, simply move them over to a matching spare pot.
Our list here shows many of the most common species of butterflies and the annuals they’ve been observed nectaring on. We’ve mined the internet, queried knowledgeable people, and included our own observations, but the list is incomplete. We’d like very much to hear from you about what annuals you’ve used and the butterfly species you’ve observed on them. Please let us know and we’ll include your data on our list, along with your name, if you’d like.