In addition to St. John's wort and Bach Flower Remedies, there are other natural means of lifting the spirits.
Among the essential oils, there are some specific ones whose benefits include a promise of happiness. These include rose, neroli, jasmine, clary sage, grapefruit, tangerine, geranium, sandalwood, palma rosa, vetiver, cardamom, bergamot, lavender, rosemary, nutmeg, pettigraine, chamomile (Roman), rose maroc, osmanthus, vanilla and basil.
Depending on the nature of your depression, low spirits or anxiety, each of these has something to offer. Not only does each oil have particular properties (consult a guide to the oils for detailed information), but you may have a special liking for one or another, which counts too. Vanilla, for example, is an uplifting oil, but you might find it too sweet, so it could get in the way of your campaign for good spirits.