I had about 5 swan plants.
I get why the rate of decline in monarchs.
They would eat a plant to destruction them move on to the next one. I lost hundreds of caterpillars. Still have some cocoons that didn't survive from last year.
They really need to come up with a better plan. Also doesn't help that swam plants are poisonous to a bunch of other animals. So can't plant them anywhere near where other animals are.