Lemon Verbena and Lemon Balm Compared

Is lemon verbena and lemon balm interchangeable in recipes?

No, they are not. Lemon verbena has a very intense lemon scent and flavour. The leaves are a delight to use in tea, preserves, baked fish, cakes and pastries. It is also increasingly used in soaps, perfumes, candles and other similar items. As one customer put it once, "you can get high on the incredible scent". The scent is intense whether the leaves are fresh or dried.
Lemon balm is unmistakably lemon-scented when you crush the fresh leaves, but the lemon scent almost disappears on drying. Lemon balm is an excellent tea herb because, while it adds a subtle flavour to tea, its effect on the heart and mind – helping to relax them – is quite potent. In hot tea I would describe the flavour as more of a warm "balmy" flavour.