How can I get to the lavender fields/countryside from Aix-en-Provence?

My boyfriend and I are visiting Aix-en-Provence in the first week of July, and he doesn't feel comfortable renting a car, so we have to rely on public transportation. Does anyone know how we can get from Aix to the country? I'm sorry if the question is naive- but I'd really love to see some of Provence's natural beauty.