not all seeed is steril & as for comming true..... you will fined some that are close to the parent different collor shades, heights, spread, etc..... Note that these are general statements & do not ally in ALL!!!!! cases

Perhaps misinformation in the articles you read or misinterpretation. Obviously, as your yard shows, not all coral bells are sterile. While seedlings may not be an exact copy of the parent they can sometimes look very close, especially when dealing with the trait of purple leaf coloration.

There are a couple varieties that do come true from seed. the one that comes to mind is the 'Palace Purple'. That's one reason why it is so common in the box stores - cheap and easy to raise from seed. Most of the unique cultivars need to be propagated through division (maybe tissue culture but I'm not definite on that one). I'm growing some from seed right now that I collected form my garden. Mine definitely were not sterile! Now there is no guarantee they will be identical to the parent plants but its fun to see what happens!