Milkweed is a plant that can be found in Red Dead Redemption 2. It will grow along the banks of rivers or near bodies of water. It has long stems and large leaves and will be covered in lilac flowers. Milkweed can be used to add poison to arrows, can be eaten to refill your Health Core, and is an ingredient in Special Health Cures. You may also need to gather it for Daily Challenges in Red Dead Online.
It should be noted, Milkweed grows in the same places in Red Dead Online, so if you need the plant for a challenge in the multiplayer portion of the game, the below will still help you.
Milkweed can be found along the banks of Bayou Nwa, and Dewberry Creek in Lemoyne. You can also find it to the west of Lagras Lake, in the Bluewater Marsh. It is not a common plant, so you might need to do some searching in different areas to find it.
It is a good idea to grab all the plants in the game as you come across them. After all, you never know when you might need them, and make sure you don’t sell your entire supply because you might suddenly find yourself in need of a plant you just sold. Just keep an eye open for Milkweed every time you go through this area, and you should never run out.