It sort of looks like spicebush....I think. The host plant for spicebush swallowtails.

'Looks to me like camphor tree/Cinnamomum camphora, a native of Asia. Spicebush swallowtails and other swallowtails who use laurels are known to lay eggs on it, so that's probably what you're seeing. Spicebush and palamedes swallowtails (another possibility) lay their white, round eggs singly on the undersides of the leaf.
Congratulations, Angie!
Sherry

I looked it up in my field guide, and the three-tailed swallowtail, widespread in Mexico, is a rare stray to south Texas - this butterfly uses laurels.
Here's a link about camphor tree.
Sherry

Here is a link that might be useful: Camphor Tree

Its so funny iv lost like 5 sassafrass trees all died and some how I got a camphor tree I didnt even plant it growing in my front yard my hubby was ganna chop it down and I saw a black swallowtail laying eggs Iv alway wanted spicebush swallowtails and never had any luck now I have over 11 eggs to keep safe.Thx goodness my hubby is a slacker hehehehe.Now its ganna stay even if it doesnt look that great coming out of my hedges hehehe.Angie

"Thx goodness my hubby is a slacker" lol angie! Sometimes it works out! :)

Yep, looks like my Camphors which also came up as volunteers. Spicebush prefer laying on it rather than the Red Bay I actually planted for it. We keep our cut down more to shrub size so that it puts out new growth that I can reach to retrieve the babies on stems. In fact, I now have 3 cats and one egg as of yesterday. They will chew the leaf and lay down some web that will curl the leaf around the cat. I love watching them change their colors from brown to green to orange. Love the colors of the male Spicebush butterflies, too. Eggs are laid singly on the back of the leaves.

I'm glad your husband is a slacker, too, Angie! Hehehe!
Sherry