2019 was an off-year for Monarchs in my yard, despite several huge HBM trees. However, the beautiful flowers dripping with nectar every morning attracted bees, gray hairstreaks, hummingbirds and, yes, Monarchs -- reason enough for me to re-plant this year. I've seen quite a number of Queens and Monarchs laying eggs (as recently as yesterday); but with all the predators about (ladybugs are so darned efficient!), who knows how many cats will make it to adulthood.

But to answer your question: yes. :)

PS A. fascicularis has done great in my yard this year. I was concerned earlier this year when a couple of very flood-y rains caused rust to develop on most of the lower leaves. But many weeks of hot-and-dry weather has taken care of those, and my 8-10 plants are now a massive, blooming grove. I have them planted in full sun, in a pretty dry area of the yard.

The HBMs are planted along the rear of this bed, and C. procera (right) are getting rather huge.

This site is a really useful tool for pinpointing natives to your area: http://bonap.net/Napa/TaxonMaps/Genus/County/Asclepias

what are the dimensions of a typical leaf? Do you know how they compare to Giant milkweed?

@ keesler: Dimensions of a typical G. physocarpus leaf? They are long and slender, growing up to 7" long x 1' wide. Very different from Giant milkweed.

HAHAHAHHAHAHAHAHAHAHHAHJHHAHA

Yes Monarch cats use Hairy Balls milkweed! I've grown it and had cats and now my girlfriend has a plant of it and its full of cats!

I lost my hairy ball plant. But yes monarchs will lay eggs on it.... I found that after it was established that my monarchs preferred it and my giant milkweed over the tropical milkweed. I live in Zone10 Florida.