Thanks to Monsanto and their product Round Up, milkweed are a lot more rare than they used to be. Many garden clubs are planting milkweed to help keep the Monarch Butterflies who have caterpillars that only live on milkweed.
Common milkweed flowers in June in zone 5. There are other types of milkweed that bloom later.Tropical milkweed flowers all summer. It blooms even after it has made seed pods. However tropical milkweed is an annual in most temperate growing zones.
No they eat milkweed and other flowers
Butterflies like milkweed. (monarchs do, at least)
The monarch caterpillar is at a high risk when they eat Milkweed. Milkweed got its name because its full of a sticky milk colored liquid. Many caterpillars get stuck in it and die. The caterpillars that eat milkweed are immune to a special toxin in the milkweed but still are at risk of dying in the sticky liquid. Butterflies do not eat milkweed. They drink nectar from flowers or juice from fruits.
Monarch butterfly larvae (caterpillars) feed exclusively on milkweed. The adult Monarch butterfly drinks the juices of soft fruits (usually fallen fruits), and nectar from flowers. It drinks the nectar of milkweed flowers, which makes it poisonous to predators.
Insect pollinators that are attracted to sweet smelling flowers. This usually includes butterflies, daytime moths, and bees. I always see a lot of butterflies, in particular, around the milkweed in my neighborhood.
Other than both are plants, there is little relation. Milkweeds have flowers, moss does not.
There is common milkweed, purple milkweed, tropical milkweed, and swamp milkweed.
If you could grow them they wouldn't be rare.
A rare flower
The Milkweed plant is south of MrBraider under a small marsh pit, it has Pink flowers on it. Simply Click on it and click 'Search' you have found the moth wings. I hope this helped. ~AlBell
They produce a bitter latex. This "milk" tastes bad to the herbivores such as deer that eat them and they leave the plant alone.