I never bother either. Basically the point of blanching greens before final cooking is to take out some of the "green" flavor, what DH calls a "sharp" flavor. Unblanched strong greens can overwhelm a dish to some people's palates - I just don't happen to be one of those people.

It sounds like gai lan aka Chinese broccoli from your description. If I were going to blanch it at all I'd definitely keep it brief and dunk it in ice water to stop the cooking. Kind of depends on how mature the particular bunch is - how thick and tough the stems and leaves are, how many of the buds have opened, etc.

Often I'll taste a bite of leaf and stem raw, just to get an idea of how strong the particular bunch is, and what kind of treatment it's going to need.