I have seen the cats feeding on my Swamp and Butterfly milkweed,, but haven't ever found an egg on anything except my common.

In my experience, Swamp is the preferred plant for egg laying.

Martha

I have 'milkmaid' and 'soulmate' and could barely keep up with the eggs and cats that I had this summer. I also had four tropical milkweed and eggs were also laid on them.

When I was scrambling for more leaves for the cats that I brought in, I found some of the common weedy milkweed and brought it in for some of them. They much preferred it, but I only had a very small amount.

I planted swamp milkweed, butterfly weed, and tropical milkweed. For me, tropical milkweed is #1 closely followed by swamp milkweed. Butterfly weed was only munched when other milkweeds nearby were defoliated.

I would avoid cultivars at all costs. I bought Asclepias incarnata 'Ice Ballet' and it wasn't touched by the monarch caterpillars.

This year, we had a lot of rain over the season and the swamp milkweed was in prime condition...got a ton of eggs along with common.

I have one 'ice ballet' cultivar plant...it didn't get any eggs but it was a popular nectar plant. I did recently put some in to feed caterpillars and they ate it without any fuss.