With Scaevola (the darker blue flowers) below it.

It's a Cleome, an annual plant. They don't transplant well so let it grow there if you can, harvest the seeds when they ripen (it can be tricky, they pop open when ripe) and broadcast them where you want them, they can also be winter sown. They tend to reseed heavily.

Tall Bellflower, American Bellflower ⇢ Campanulastrum americanum

Maybe Erodium texanum?