In those conditions, you can also grow Spanish Lavender here. I have some in a well-drained bed in full sun. Has done well for me for several years.

-T

As you mention, Mona Lavender isn't a variety of lavender at all. It's a plectranthus, like Swedish ivy, with no odor or anything. It is a beautiful plant and will grow and BLOOM fine in shade, though it does freeze in the winter. But it's only called Mona "Lavender" because of the bloom color. It doesn't require the same growing conditions as true lavender, as it likes rich soil, evenly moist, and no direct sun.

True lavenders really want some sun. At least 4 hours or so, in the mornings. You are far enough north to grow some of them with no problem, but like most herbs, they don't want extremely rich soil, they do want to be kept on the dry side, and they do want sun.

Hope this info helps in making a decision.

Marcia