I think redosier means red-stemmed, but I really don't know what kind of plant this is. My East Vancouver friend has two. Their growth habit is doubtful; at present they are very small trees, with bare trunks up to maybe a metre and then all their leaves in a big ball shape on top. (I expect that's the result of previously overzealous pruning by someone.) However, she moved both of them into a better location in her back yard, and, after a couple of seasons of TLC, they are both growing very fast this year. But what are they? Thanks for identification.
Cornus sericea has smooth-edged leaves, not toothed. The same for Cornus alba, which is a similar plant. While the effect is dogwood-like, I can't immediately think of any dogwoods with serrated edge leaves of that type.
Wow. Now that you've given me the name, I find that this plant has quite some status with the Royal Horticultural folk. My friend will be delighted. She has always said that these two youngsters seemed special. Apparently they were in pretty bad shape when she first began renting her house about two years ago. Thank you both very much indeed, Geoff and Ron.