I've been confused by USDA zones lately. If I study the map closely, I'm in zone 3a.. but about 15 miles west of here, you enter zone 3b, and 10 miles east of here, you're in 2b.
Our cabin straddles the 2b/3a line almost exactly, but many species hardy to zone 4 grow there quite well. American hazelnuts thrive right next to arctic dwarf birch, which I didn't know grew in Minnesota until I found it growing along the lake shore.
My question is: Should I follow hardiness zones pretty closely, or can I experiment?
For example, black walnut trees are considered hardy only to zone 4, but are planted up here and do quite well (they get large and dense, but do not get as large as further south)... while my dwarf Alberta spruce have not done well (my fault... too much snow plowed on top of them and not enough water in the fall... so I planted new ones further back and have been watering more along with some fertilizer).
Has anyone here had success with some trees/shrubs supposedly hardy to zone 4 that do well in zone 3?