Baptisia (false indigo)

Says it grows 4-5 ft is that true the one I saw was a smaller looking shrub

- It is an herbaceous perennial, the plant dies to the ground every winter. They return and regrow in the spring, flowering during the late spring. It looks like a shrub but isn't. Most Baptisia grow 3 - 4' or maybe a little taller for some varieties but I have never seen any baptisia grow 5 feet tall.

4-4.5 ft tall is about right, but maybe a bit shorter to 3 ft depending on the cultivar; there may be even shorter cultivars available IDK. As a rule, younger plants tend to be shorter until they're established, so what you saw could either be a young plant or a shorter cultivar.