Information for Residential Gardeners

Guidelines for Purchasing Milkweed Plants

• YES! Purchase California native milkweed species that are appropriate for your location and ideally, were locally sourced.
• YES! Ask the nursery about their milkweed sourcing and growing practices to ensure their milkweed plants are pesticide and pathogen free. Below are some questions you can ask to gather information about a nursery’s milkweed plants.
• ~ Where were the seeds of your milkweed plants collected? or, if the nursery did not grow the plants from seed, Where are your milkweed plants from? (If the latter question provides you with the name of another nursery/grower, be sure to ask that vendor the remainder of the questions in this list.)
• ~ Have your milkweed plants been treated with Bt?
• ~ Have your milkweed plants been treated with neonicotinoids (also known as “neo-nics”)?
• ~ Have your milkweed plants been treated with pesticides of any kind?
• ~ Do you use phytosanitary practices?

• NO! Do not purchase tropical milkweed (Asclepias curassavica)—this species can harbor OE, a parasite that kills monarchs. For more information on this, see this helpful fact sheet from the Monarch Joint Venture.

‍Guidelines for Purchasing or Collecting Milkweed Seeds

• YES! Before purchasing milkweed seeds, ask the nursery or seed bank about their milkweed seed sourcing and production practices to ensure the seeds were collected responsibly and are pesticide free. Below are some questions you can ask to gather important information about a vendor’s milkweed seeds.
• ~ Where were your milkweed seeds collected?
• ~ Were the seeds collected responsibly?
• ~ Were the seeds treated with neonicotinoids or other pesticides?

• YES! Before collecting seeds, make a plan for responsible seed collection and successful seed germination.

• ~ For a short introduction to best practices, see the Xerces Society’s guide to Native Milkweed Planting and Establishment in the Western United States.
• ~ For a more in-depth dive into milkweed propagation and establishment, refer to this incredibly helpful guide from the Xerces Society: Milkweeds: A Conservation Practitioner's Guide

• More information about successful milkweed establishment can be found here.

• YES! Before collecting milkweed seeds, please take the following precautions.
• ~ Ask for permission to collect seeds from the landowner or land manager, and acquire a seed collection permit, if necessary. If you are unsure about whether you have permission to collect seeds, err on the side of caution and do not collect seeds.
• ~ Properly identify the plant from which you intend to collect seed as a California native milkweed species.
• ~ Consider the conditions of the location where the milkweed plants from which you intend to collect seed are growing, and consider where the collected seeds will be planted. The seeds you collect are likely to grow best in similar conditions to those where the mother plants were growing.
• ~ Ensure that the milkweed seed pods are ripe and ready to harvest.

• No! Do not collect seeds without permission.
• No! Do not deplete wild plant populations by overharvesting seed. A recommended guideline is to collect no more than 20% of the seeds within a population on a given day.

Resources to Help You Find Milkweed Plants and Seeds to Purchase

• Xerces Society’s Milkweed Seed Finder
• Calscape’s Listing of California Native Nurseries