Monarchs and Milkweeds
At our January meeting, Barbara Keller-Willy, Director of Monarch Gateway & President-elect for NPAT discussed methods of propagation she uses in her Monarch Host Cities Project where cities partner with Monarch Gateway to improve & add more native milkweed habitat to aid in Monarch Conservation. Highlights of her presentation:
- Monarch Gateway seeks to create contiguous pollinator habitat across the coastal and central flyways of Texas through partnerships with 146 NGOs (non-governmental organizations) across Texas.
- She partnered with other organizations to collect regional milkweed seed, grow them out & return those plants to the regions where the seed was collected. In the first year, they started with 300 seeds & only 3 plants survived. Now that they have the propagation technique mastered, they will have 200,000 plants for 2017!
- Barbara referenced the tropical milkweed research by Dara Satterfield, PhD candidate at University of Georgia. Satterfield works closely with Monarch scientist Dr. Sonia Altizer, the foremost expert in the country on Ophryocystis elektroscirrha (OE). The protozoan disease infects monarchs & other milkweed feeders, often resulting in butterfly crippling or death. Because tropical milkweed tends to grow year-round in warmer regions of Texas, it may promote disease.
- Cardenolides are the chemical in milkweeds that monarchs feed upon, which in turn makes monarchs toxic and bitter-tasting. The cardenolide values of various milkweeds determine whether those species are more attractive to monarchs. Note the values below for green milkweed (Asclepias viridis LA) & antelope horn (A. asperula). Not shown on graph: tropical milkweed (A. curassavica) which has values at 1421.
- Barbara recommends collecting seed & growing milkweed from within a 50 mile radius.
- She recommends planting native milkweeds, as well as nectar plants to bloom continuously from spring to fall; plant in clumps; & use naturescaping technique (cast seeds out & let them grow where they will).
- Her milkweed sprouting method is:
- Prepare seeds with 4 cups vermiculite in a 1 gallon baggie & moisten
- Cold stratification for 3-6 weeks at 34F
- Pull from refrigerator, moisten vermiculite, place in indirect sun
- Transfer sprouts to deep pot (10” tree pots) after the 1st true leaves form
- Soil with some clay, organic content
- Place in partial shade
- Water needs are determined by size of pot & soil type – Milkweed needs consistent watering even when dormant until age 2 (essentially in nature, milkweed propagates in wet years)
- By 6 months, the bacteria in the soil has developed a relationship with the milkweeds so you shouldn’t separate them from the soil.
- Monarch Gateway provides milkweed propagation workshops & Barbara would be willing to offer one for this area.
- Xerces Society Milkweed Propagation Handbook: https://www.fws.gov/southwest/es/Documents/R2ES/Pollinators/8-Milkweeds_Handbook_XerSoc_June2014.pdf