They struggle in zone 9 and 10 even with top professional care. They are native to elevations above 4,000 feet in my area. They thrive in cooler , humid sites, here on vancouver Island. The humidity will not be an issue but heat can be! I keep mine in the shade during the hotter part of the summer. Basically they are an understory tree, flourishing in the shade of Douglas fir and other taller trees. Not sure what the statistics are but i would be concerned if your summer temperatures tend to be above 80 degrees farenheit regularily!
I am zone 5 / 6 so I am ok there but finding one is an issue.
I am pretty sure if you were selling them you would have your hands full. If you ever decide to do so let me know.
mertensiana inhabit higher elevations with cooler air and lots of humidity, snow and cooler winters. At lower elevations humidity and shade become more important and cooler winter temperatures as well. I use shade cloth, shadier spots and lots of foliage spray when watering. My elevation is 600 ft above sea level. They are collected at 4,000 ft plus normally.
Mine are all collected from similar elevations 4600 ft to 5200 ft above sea level, color is darkest in shade and cooler areas, rather than warmer with more sun. The tree's collected at lower elevations are often lighter in color and Western Hemlock species. The foliage loves to be showered frequently as they would be with mists and dew in there natural habitat.
That’s helpful! My 2018 collected tree (2950' elevation) is the lightest in color. I had it in way too much sun and recently moved it to afternoon shade. I’ll spray the foliage regularly from now on. It’s definitely the mertensiana species but I’ll take a closer look to see how much heterophylla might be mixed in.
