Q.Butterflies
what plants attract Butterflies When is the best time

Certified GKH Gardening Expert
To attract the most butterflies, it is best to grow, not only the nectar plants for adult butterflies, but some of the host plants for the caterpillars to eat. To find out which butterflies are present in your area, you can contact the area university extension office, or search online.
Then you can include host plants among the nectar plants. Many of the host plants you can find at native plant nurseries. Milkweed, which is the host plant for monarch butterflies, can often be found in any nursery or garden center. Host plants for the black swallowtail, which is the New Jersey state butterfly, are easy-to-find herbs: parsley, fennel, and rue (rue is also a host for the Giant swallowtail).
Here is more information:
https://www.gardeningknowhow.com/garden-how-to/beneficial/attracting-butterflies.htm
https://www.gardeningknowhow.com/garden-how-to/beneficial/butterfly-garden-plants.htm
https://www.gardeningknowhow.com/garden-how-to/beneficial/plants-for-butterfly-eggs.htm
https://www.gardeningknowhow.com/garden-how-to/beneficial/fall-fuleing-station-drifts.htm
https://www.gardeningknowhow.com/garden-how-to/beneficial/attracting-monarch-butterflies.htm