I've seen this shrub in the wild and it also pops up in gardens (Calgary area). The leaves are kind of silvery and it spreads. I've not yet seen flowers on them.
Wow. Here's a webpage with good photos: Shepherdia canadensis (Canada Buffaloberry): Minnesota Wildflowers. Also called Soapberry, because the fruits are soapy and bitter. Thanks for posting this.
A bit more info. This plant (Shepherdia canadensis) is a nitrogen-fixer. Its relative, Silver Buffaloberry (Shepherdia argentea) is also a nitrogen-fixer. They are both native to Canada, so are not considered invasive. They are very cold-hardy, to Zone 2, I believe. They are slow-growing and do not get very tall. They are both dioecious, which means each plant is either male or female. Both plants are needed in order to produce berries. Berries are produced on the female plants. I've started a few Silver Buffaloberry plants in Northern BC. There is a plot there with terrible soil; hopefully, some Nitrogen-fixers will help improve it. And winters are cold; a plant extremely cold-hardy is necessary. Also, I think Silver Buffaloberry plants are more attractive than Canada Buffaloberry. They look like small olive trees, which is about as close to olive trees as I'll get in a zone with such cold winters.
