Sylvia, I got my first Japanese maple last year from Sue Taynor. It was about 18 inches tall and so far this year, it's about 26 inches tall. Still in a pot till I figure out where to put it, but doing fine. Don't have any other personal experience but my parents have a big one that's been doing great for 20 years.
It may not have been bad mulch. Between last summer and now, looks like I completely lost about 1/2 to 2/3 of my hostas, and I don't mulch them at all during the winter. I'm still sick that I lost my 8-year-old Red Octobers that circled my tree.
Most of the surviving ones dwindled in size. My big, big Sagae has only TWO eyes coming up. Same with Elvis Lives and Guacamole. We had that really tough summer in 2011, and they all survived that, but they need chill hours to recover, and we haven't had that for 2 years now. I only have a few that are still looking good. Even one of my undulatas is struggling. I didn't think anything would hurt those.