Orange mint (bergamot mint) has a floral, citrusy scent distinct from other mints, closer to Earl Grey tea than to peppermint. The broad, dark green leaves go into fruit salads, cocktails, iced teas and desserts, and the dried leaves hold their fragrance well for tea and potpourri.
It grows like every other mint, which is to say too well. Plant it in a container or a bed with a solid edge, because the runners travel a foot or more a season and come up through anything. Give it rich, moist soil and sun to part shade. Harvest before it flowers, when the oils are strongest, and cut the whole plant back by half after the main flush to get a second one.
The lilac flower spikes, if you let them come, are covered in bees and small butterflies through late summer. It is a sterile hybrid and does not come from seed; take a cutting or a rooted runner. Cut it to the ground in late fall. Deer leave it alone.
Powdery mildew
White or grey powdery coating on leaves - usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.