Are there any good herbal medicines to help with depression?

Not really. St johns has a lot of interaction with medication and surgery and takes a while to get out of system. Aerobic exercise and avoiding processed foods and poorly balanced diet are of great benefit.
Yes. St. John's wort is the one most cited in literature. However dosages need to be in the 2-4 gram range daily and it is difficult to know how much one is getting since these and other herbal medicines are not well regulated. It can interact with meds as well. Also same supplements have been reported to be helpful along with good steady b vitamin supplementation as adjuncts to medication.