Amber Jubilee Ninebark, Physocarpus opulifolius ‘Jefam’, is a tough plant and cold hardy to zone 2. Colorado Extension has a list of plants that do well at higher elevations. And, they include common ninebark, Physocarpus opulifolius, as a plant that can handle conditions up to 8,500. However, I found another reference that shows it can handle up to 8,000 feet. I think it’s worth trying. But, that’s how I garden! If you are more cautious, you might go with barberry, potentilla, cotoneaster or sumac instead.
Thanks for writing!