The slugs l have seen around my home are usually really small, less than an inch and gray. The slugs create no problems for the plants, because of natural predators.
Anolis carolinensis, the green anole, eats them. This is the second year l have had my potted plants in the back yard and the anoles have had a population explosion.
Love them lizards.
And frogs, toads and some snakes eat the slugs. I have lots of toads and frogs and some snakes. There is a large pond between my sisters house and mine. The frogs are so loud at night you would think they've come inside to serenade me.
Them slugs up in Washington are humongous!