Thank you for reaching out to ask2.extensi9n.

The best lavender varieties for the north are all cultivars of Lavendula augustifolia, the so-called common or English lavender. (For French lavender, you need to visit France or Oregon.) ‘Munstead’ and ‘Hidcote’ are the two hardiest cultivars and are the ones you are most likely to see in northern gardens. Both are usually rated as USDA Zone 5 hardy, which means they will need a protected spot in most zone 4 (that’s St. Cloud southward in Minnesota) gardens. Hidcote grows a bit taller (18 inches, more or less) than Munstead and it has a grayish-green foliage and deep purple flowers. Munstead is shorter (12-15 inches). Both plants are highly aromatic and just walking by them you will catch the delightful scent of lavender. Phenomenal™ lavender is a new variety that some growers rate as hardy to USDA Zone 4. It also deals well with hot, humid summers, unlike other lavenders. I have not grown this variety, but may be worth a try.

I’ve had lavender for quite a few years and it does ok.  It’s never been anything I could cut and dry.  I live in southwest MN near Iowa and So. Dakota.