"Yes, it's perfectly fine to use two or more herbs. In fact, in my experience, this actually increases the magickal potency of the spell/charm/talisman. In my spells, I always compile a huge list of herbs, stones, colors, and oils useful for what I need, then gather as many of them as I can to use in a single spell. I then perform the spell, keeping the candles from the spell to burn over three days so they have completely burnt out by the end of the third day."