Native plants are best for attracting Monarchs. The female Monarch lays her eggs only on Milkweeds - plants in the Asclepias genus - where the caterpillars will hatch, feed and grow before forming a chrysalis. Make sure the Monarchs stay in your garden by including some of their favorite nectar plants, too. Late season blooms, such as asters and goldenrods, are a critical source of nectar during their fall migration to Mexico.