It is very important that you supply the correct varieties of milkweed for your specific location.

For instance, I live in the Missouri Ozarks. The recommended varieties are: http://www.xerces.org/wp-content/uploads/2013/07/Milkweeds-of-Central-US_plus-vendors_XercesSociety.pdf

• Swamp Milkweed (Asclepias incarnata)
• Common Milkweed (Asclepias syriaca)
• Butterfly Milkweed (Asclepias tuberosa)
• Whorled Milkweed (Asclepias verticillata)
• Green Antelopehorn (Asclepias viridis)
• Purple Milkweed (Asclepias purpurascens)

Sunset Flower AKA Scarlet Milkweed AKA Tropical Milkweed (Asclepias curassavica) is not recommended for a Monarch butterfly larval plant in North America. Tropical Milkweed is native to South America. It is now becoming an invasive species in the southern states of America. The Monarchs that consume this variety become prey to additional parasites. Subsequently, this variety weakens the larvae and butterfly. Lastly, the Monarchs are not migrating to Mexico because they have a constant supply of the wrong food.

Check out these links for native milkweed in your area:

http://www.xerces.org/wp-content/uploads/2011/03/xerces-nrcs-california-milkweed-guide.pdf

http://www.xerces.org/wp-content/uploads/2011/03/NativeMilkweedsGreatBasin.pdf

http://www.xerces.org/wp-content/uploads/2011/03/SE-Monarch-milkweed-butterfly-host-plant-brochure-final-2012.pdf

http://www.xerces.org/wp-content/uploads/2014/03/Monarch-Butterflies-East-Region.pdf

http://www.xerces.org/wp-content/uploads/2015/03/Monarchs-Milkweeds_Northern_Great_Plains.pdf

Don’t forget nectar producing plants for your Monarchs as well. Some of their favorites include:
Buckwheat (Eriogonum)
Butterfly Bush (Buddleia)
California Lilac (Ceanothus)
Citrus (Citrus)
Coneflower (Echinacea)
Coreopsis (Coreopsis)
Cosmos (Cosmos)
Daisy (Aster and Chrysanthemum)
Dianthus (Dianthus)
Heliotrope (Heliotropium)
Lantana (Lantana)
Marigold (Tagetes)
Milkweed (Asclepias)
Pincushion Flower (Scabiosa)
Rabbit Brush (Chryssothamnus)
Rock Cress (Arabis)
Salvia (Salvia)
Senecio (Senecio)
Star Clusters (Pentas)
Sweet Alyssum (Lobularia)
Verbena (Verbena)
Wall Flower (Erysimum)
Zinnia (Zinnia)

Papa