The ONLY plant that monarch caterpillars can eat is milkweed. There are many varieties, so it’s best to buy the ones that are native to your area if you’re interested in helping the monarch butterflies reproduce. It’s kind of like a science experiment in your yard. I have learned things about these amazing creatures through seeing them live through their life cycle that I never knew before. And it started with one plant.
Sure these little guys will start off tiny and within a matter of days double their size over and over. In the process they will systematically eat every single leaf and flower off your milkweed. But it’s okay. Because milkweeds are built for this. They will grow back. And then a monarch or two will lay eggs on it again and it’ll get mowed again and it will again grow back.
So when my daughter and I counted 38 baby caterpillars on our ONE milkweed about a week ago, I knew they would run out of feasting material fast. So I went to the nursery and bought 3 more plants. Then 2 days later I bought 6 more. And they were finally happy and fat and had had their fill of the buffet. Whew! It was then that I got worried. They were lethargic and many had curled up. I calmed my concerns with a quick internet search informing me that they do this before getting ready for their next stage in the chrysalis.
And then they started disappearing. They were off to find their magic place to make their final transformation into a butterfly. I managed to find 4 of them in a nearby tall bush called “pink breath of heaven”. When they attach themselves to wherever they have chosen and form their “J” as my daughter likes to call it, they are C O M P L E T E L Y still. Take a glimpse at the 3rd and 4th pictures below. That’s the same caterpillar before and after the chrysalis. And the time in between taking those shots today? 2 hours. That’s it. You can youtube a video of a time lapse of this process if you’re interested. Pretty amazing. Now we wait!
Bountiful Backyard 
Wow! I did not realize that it only takes a couple of hours, that is truly AMAZING! Love this post, I will keep my fingers crossed that they will all make it to Monarch Butterflies.