Gardening remains most common among the baby boomer set, but its popularity may be on the rise as more people focus on the home and the activity is portrayed as a hobby, not yard work.

Given that every major mass merchant, department store, and home-improvement center in the US has a gardening section, people who putter around working on their lawn, flower beds, and vegetable patches may be one of the largest - yet quietest - consumer groups. Virtually every major ...