This year represents the smallest population ever for the beautiful Monarch Butterfly. Habitat loss and pesticides have caused their populations to dwindle from the hundreds of millions to less than a few hundred thousand this year. The biggest problem is the loss of milkweed, which is the only plant the larvae feed on.
In addition for those Monarchs passing through - plant butterfly bush, lilac, crown flower, bee balm, cone flower, phlox, black eyed Susan, viburnums.
Here is a link that might be useful: more about monarchs click here