No, it is not aggressive at all. But, if you are in Southern CA, you could have a problem, as S. patens does not like strong sunlight and high temps, this could cause it to wilt and even die. But try it in the coolest shadiest part of yiur garden. Mature size is approx 18" x 18". (The form known as 'Guanajuato' can be 3 times larger.)

Cool and shady--okay, I will give that a try.

I appreciate your help. Thank you!

Salvia patens would also prosper if it has drainage, and protection from tuber-eating critters. Working in some crushed rock or expanded slate pellets will help.