Attribute-granting herbs always have stronger effects when brewed into potions, but you will find far more of them than you will of the Hero's Crown, which is the required base for permanent potions. Pick one type of attribute-boosting plant to use the Hero's Crowns with and eat the other types directly.
Note that you can also boost attributes through cooking. Cooking uses vegetables instead of herbs and doesn't require a skill, but you will still need the appropriate recipe and the base ingredient (bag of spices). Meals don't boost attributes as significantly as potions do, but it's certainly useful as a secondary method (especially if you aren't going to learn alchemy).