Yes, new planting in a 6ft cedar planter (also new) with some ornamental and also a parsley plant next to it, which we also harvested a bit and it's still doing ok. Yes, it's on the sunny side of the house, (morning shade from the house, then unfiltered afternoon sun from about 1pm till 5pm) and it's been hot here in the NW. I filled the planter with general purpose potting soil. I use a bit of general purpose fert on new plantings, but usually don't add any fert after that. I haven't used liquid fert. Watering schedule is daily most mornings, watered at the base.
Sounds like sun burn is the most likely reason? Should it be moved to it's own container and a shadier area? How big do these get?