This study evaluates the success of various milkweeds in three elevation ranges: Mid-Elevation range of 3,000-6,500 feet, including the regions of Camp Verde, Rimrock, Clarkdale, and Sedona and Oak Creek, the Prescott Valley range of 4,800-6,200 feet and the high-elevation range of 6,500-7,300 feet, inclusive solely of Flagstaff. A common garden experimental design is used, which means planting the same milkweed species in similar physiological condition and from the same genetic source in each of the experimental gardens. Milkweed species were selected based on the known elevation distribution of that species and published literature. Not all milkweed species are grown at both elevations, but as much overlap as possible is desirable.


In the Desert Southwest there are more than 40 species of milkweed which is more than 50% of the total diversity of milkweeds in the continental US. Arizona has the second greatest diversity of milkweeds next to Texas. The criteria we used to select candidate milkweeds for this study included: 1) known distribution within Arizona based on SEINet, 2) known distribution outside of Arizona but within major plant communities (eg Mohave Desert) that occur within Arizona, 3) availability of seed, 4) unique characteristics of a species that offer advantages to home gardeners 5) species that are currently produced and sold in commercial nurseries in Arizona. All of the milkweeds in this study are native to Arizona.











    Asclepias asperula                              Asclepias subverticillata                  Asclepias tuberosa                          Asclepias speciosa 




Cooperating organizations include: NAU Research Greenhouse, Red Rock State Park, Verde Valley School, Coconino County Master Gardeners, Maricopa County Master Gardeners, Yavapai County Master Gardeners, Arboretum at Flagstaff, Boyce Thompson Arboretum, Desert Botanical Garden, Southwest Monarch Study, University of Arizona Cooperative Extension, Ecological Restoration Institute. These public education partners offer the opportunity for future opportunities to engage in wildland restoration and demonstrate various aspects of our project.  

Citizen Scientists are selected from a pool of Master Gardener (MG) applicants from Coconino and Yavapai Counties. Selection of candidates will be based on uniformity of the site, and those who can meet the needs  of this project. There is a MG coordinator for each elevation. The MG coordinators major responsibility is to organize the distribution of seedlings, provide general advice and organize seed collection.  Once the milkweed seedlings are in the hands of volunteers it is up to them to do the best they can to grow the milkweeds.



Citizen volunteers will be required to document weekly observations on milkweeds and insects, and then submit the data sheet twice within the growing season (found under the "Data Collection" tab.) These reports will ask specific questions about the height of the individual species, how well the plants are growing, evidence of flowering, presence of pest insects and monarchs, when were eggs deposited and when caterpillars first appear. The goal of this data collection is to analyze if the plants are doing well and if they are attracting monarchs.  The information gathered will be serve as recommendations for growing milkweeds and help formulate testable alternative hypotheses for future projects.