Harvesting Milkweed

When to harvest:

Asclepias exaltata (Poke milkweed) – All October
Asclepias incarnata (Swamp milkweed) – Late September-early October
Asclepias purpurascens (Purple milkweed) – Early October
Asclepias syriaca (Common milkweed) – Late September-October
Asclepias tuberosa (Butterfly weed) – Late September-October
Asclepias verticillata (Whorled milkweed) – Mid-Late September
Asclepias viridiflora (Short green milkweed) – Mid-Late September


Asclepias incarnata (Swamp milkweed) – Late September



The list of the milkweeds we are targeting for restoration can be found in the Milkweed Regions text and a description of each species is provided in the Milkweed Profiles. We will continue to add images to the Milkweed Profiles and will progressively add a narrative describing the habitat requirements for each species. Please consult these references to determine which species to collect in your area.

We need your help in collecting milkweed seeds! The Bring Back the Monarch Campaign starts with seeds. We need the seeds for seed mixes for restoration and for nurseries so that they can produce the young plants (plugs) needed for restoration and plant fundraisers.

There are two ways you can help:

1) Collect the pods, process (clean) the seeds and send them to us, and we will reimburse you for the shipping.

2) Collect the pods, dry them and send them to us. Again, we will pay the shipping.

Please use a separate container for the seeds of each milkweed species.

To be sure that the seeds you collect are used in your region, we need the following information on each seed collection:

Your name, address and email.
The date, county, and state of the collection.
The species collected.

Notes on the size of the milkweed population, e.g. large, medium, small, one or many sites, etc., would also be helpful.

What, when and where to collect:

  • Only collect the milkweed species targeted for your region.
  • When the pods are first beginning to split (ripe but as yet to open pods should split upon touch and the seeds should be brown or “browning up”). Do not collect pods in which the seeds are white, cream colored or pale.
  • Be sure to obtain permission before collecting on private property or federal, state or county properties.
  • Be safe. Please do not collect along busy highways.
  • Do not collect seeds of rare or endangered milkweeds.

Genetic diversity

Most milkweed species appear to be genetically diverse, and it is important to incorporate as much diversity as you can into your sampling of pods. You can easily accomplish this by collecting your pods from more than one site.

Species that form clones present special problems in that all of the ramets (stems) represent the same genotype. Fortunately, A. syriaca (common milkweed) is the only species on our target list that forms clones. To obtain a fair representation of the genetic diversity of this species, the pods should be collected from a number of clones scattered over several sites.

How much should I collect?

Collect as much as you can. Many pounds of milkweed seeds are needed for seed mixes used in roadside or landscape restoration. Two to four onion bags of pods will yield about one pound of seeds.

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