Why Grow and Sell Milkweed?
Milkweed declines and other stressors such as limited nectar resources, insecticide use and climate change, are associated with declines in migratory monarchs over the past 20 years. Since the late 1990s, the eastern migratory monarch population decreased by 84%. The western migratory monarch population in coastal California decreased by 74% over the same time period. To compensate for the loss of milkweed, gardeners in the US and Canada are helping monarchs by planting native species of milkweeds, and by keeping milkweeds safe from pesticides. While milkweed is essential for monarch reproduction, it also benefits many other species such as bees and hummingbirds. Milkweeds are now an essential plant for pollinator gardens. By growing and selling native milkweeds, nurseries can provide a valuable public service and enable gardeners to contribute to the monarch recovery.
The following fact sheet is a guide for nurseries to help meet consumer demand for pesticide-free milkweed for monarchs and other pollinators in the United States.
Why is it important to sell native milkweed species?
In spring, native milkweeds emerge from dormancy as the monarchs migrate north from Mexico. Females lay eggs on milkweed throughout the spring and summer in the U.S. and Canada. In late summer, shorter days and cooler nights signal to monarchs that it is time to stop laying eggs and to start migrating south to return to Mexico. These same environmental cues cause native milkweeds to turn yellow and die back for the year. However, exotic tropical milkweeds such as A. curassavica can grow year-round in mild climates and increase monarchs’ risk for becoming infected with a debilitating parasite (Ophyrocystis elektroscirrha). [3,4]. Given the risks associated with year-round milkweed, we recommend that nurseries and gardeners replace sales of tropical milkweed with native milkweed species and native nectar plants.
Milkweed is in demand!
Several recent surveys show that customers are interested in purchasing and willing to pay for monarch-friendly plants. One study found that while 24% of American households want to grow milkweed, only 4% currently have milkweed in their gardens. This same study showed that consumers are willing to pay, on average, $4.78 per household – or $6.64 billion toward purchasing monarch-friendly plants and donating to conservation organizations. In a separate survey of nurseries conducted by Project Monarch Health at the University of Georgia, 96% of nursery businesses reported that customers ask for milkweed and 66% of businesses reported that customers specifically ask for “native” milkweeds. The challenge is to turn this demand into actual plant sales. There is clear potential to increase profits through the sale of native plants, as illustrated by one nursery which had a 33% increase in revenue from promoting native, pollinator-friendly plants. Nurseries are also an excellent place to spread awareness to consumers about the importance of native plants in providing habitat for pollinators.
Tips for increasing customer interest in milkweed:
- Display native plants together and label them so that they are easy for customers to find. Labeling and other promotional efforts can influence consumer behavior.
- Label milkweed as the primary monarch caterpillar food plant. Include a photo of monarch caterpillars so that customers know what to look for.
- Offer deals bundling milkweeds with native nectar plants to encourage gardeners to grow plants supporting all stages of monarchs and pollinators.
- Provide information for projects like the Million Pollinator Garden Challenge, which has registered a million public and private gardens and landscapes to support pollinators and supply hand-outs for customers to establish their own monarch gardens (e.g., handouts such as this one can be printed for gardeners).
- Emphasize that native milkweed is a perennial and will return for several years.
Tips and Resources for Native Milkweed Propagation
Xerces Society: Project Milkweed
- Milkweed Seed Finder
- Milkweeds: A Conservation Practitioner's Guide
- Managing Milkweed Crop Pests
- Regional Milkweed Guides
Monarch Joint Venture Handouts
Resources for Finding Native Milkweed Seeds and Plugs
- Monarch Watch Milkweed Market Vendors: a list and a map of more than 200 vendors that sell native milkweeds
Plugs and plants of a limited number of milkweed species
Milkweed Propogation Resources
Growing milkweed plants from seed requires understanding the specific requirements for successful germination and growth of each milkweed species. For example, some species require a cold and moist treatment of seeds (stratification) for a number of days before sowing. Best practices for germinating seeds and producing transplants have been studied for numerous milkweed species and protocols are available online for 11 species.
- Plant Ecology, Seed Production Methods, and Habitat Restoration Opportunities
- Native Plant Network propagation protocols
- Some native milkweed species can also be propagated by root cuttins or rhizomes, as described here.
Regional Monarch Nectar Plant Guides
Monarchs eat milkweed as caterpillars. Monarchs drink nectar from flowers as adult butterflies. Adult butterflies depend on diverse nectar sources for food during all stages of the year, and especially during the spring and fall migration.
A guide to the best native, commercially available monarch nectar plants is provided on the Xerces Society webpage.
Managing Milkweed Crop Pests
Increasing the availability of milkweeds is critical to monarch conservation, but seed production can be difficult. While monarchs are the most well-known milkweed specialists, other milkweed specialist insects can cause damage to valuable milkweed crops. Our guide provides management strategies for dealing with common milkweed pests including aphids, milkweed bugs, and milkweed beetles. Learn more.
Tips for Dealing with Milkweed Pests….and going Pesticide-Free
Insecticides are known to reduce monarch caterpillar growth and survival and affect butterfly flight and navigation [6, 7]. It is critical to avoid using pesticides, especially systemic insecticides, on milkweed plants and to use an integrated pest management approach. Systemic insecticides, such as neonicotinoids, are generally harmful to monarchs and other beneficial insects, and have persistent effects that last long after the plants are purchased.
- Common pests like aphids and large/small milkweed bugs can appear unattractive, but if plants are otherwise growing, moderate numbers can be tolerated. The most pronounced damage may be a reduction in seed production. To learn more about milkweeds’ natural enemies and how to manage them, see Milkweeds: A Conservation Practitioner’s Guide.
- Signs can be placed on plants informing customers that aphids and other insects on the milkweed plants are an indicator that the plant is pesticide-free. Once plants are outdoors in a garden, natural enemies like ladybugs and parasitic wasps will keep the pest population at bay.
- If monarch or queen caterpillars are eating the milkweed, inform customers that these are butterfly larvae. Chewed leaves are a sign of the plant doing its job as a food plant for caterpillars.
- Some insects, like aphids, can be blasted off plants with a water hose or squashed by hand.
- Avoid over-watering and over-fertilizing to minimize pathogen and pest pressure.
- In cases where chemical pest control must be executed, consider using insecticidal soap that is not long-lasting and can be rinsed off. Avoid neonicotinoid based insecticides.
- Maintain genetic diversity in milkweed populations. If all seedlings come from the same or a few parent plants, they are more likely to be vulnerable to the same pests or diseases.