I'm guessing you have lots of predators that are eliminating the caterpillars before you can find them. There is a big field by me full of common milkweed. Easier to find monarch cats there earlier in the summer because later in the summer, the plants are crawling with predators.

Years ago at my first house, I watched mama monarch laying eggs on numerous plants while I did yard work. I went to collect the eggs some hours later and they were gone. My memory is I thought little spiders were the culprit. Anyway, that taught me to grab them as soon as mama monarch has left the area (don't want to bother her while she is working).

In my 40+ years of looking for monarch cats, I've had much better luck finding them on plants that were basically by themselves. An example would be 2 or 3 milkweed plants that sprung up in a parking lot. Predators aren't there because prey is scarce. Unfortunately, you don't find those parking lot milkweeds these days. I think that is because in the '70s, you had to pull or cut the weeds but these days the landscape crew nails them with a weedwhacker or RoundUp.

Agreed that you have the right one. Life as a monarch is tough! I remember hearing something like 90% of monarchs don't make it from egg to chrysalis. You can collect the eggs soon and raise them inside. Search the undersides of your leaves.

Thank you both. I have a friend who raises Luna moths so I will ask her for help. I just wanted to make sure this was the right host plant.