Monarchs rely on nectar from a variety of flowers to provide energy through their breeding season and migrations. The energy demands of flight are significant, and inadequate food sources timed with key flight periods can impact the number of monarch butterflies successfully arriving at overwintering sites. Development, habitat conversion and competition from invasive species have reduced the availability of natural food sources. Changes in climate can also dissociate bloom time from monarch arrival. One way that we can assist monarchs along their challenging migration is to provide nectar-rich flowers that bloom where and when monarchs need them.
Currently, monarch conservationists have lists of butterfly nectar plants that can be used to inform their gardening and habitat restoration efforts, but these lists are not designed to ensure nectar supply timed with monarch breeding within or migration through each region. Thus even recommended plantings may not adequately support monarchs through critical periods. The Pollinator Partnership has synthesized data on bloom phenology of native monarch nectar plants with timing of monarch breeding and migration through the eastern U.S. and has developed nectar plant recommendations to support the eastern monarch migration. This nectar plant selection to support monarchs that can be used by home gardeners, land managers and other concerned individuals to select nectar plants that will support monarchs from their spring arrival through their fall migration in each region. Eco-regional "Fueling Zone" guides can be downloaded from the Pollinator Partnership website: http://pollinator.org/monarchfueling.htm.