Don't worry, you didn't do anything wrong. It's common for elephant garlic to make singles.
The odds are that most of the others will be more garlic like.

Timing when to dig elephant garlic is tricky and I find it better to err on the safe side. If you dig early it's maybe not quite as big, but if you wait too long it splits and does't look good for sale and won't keep quite as well (this doesn't matter if your not selling it or don't have much to store).

-Mark

This is my first year growing garlic, too. I dug mine a little early due to gopher activity. (Scapes appeared, and I cut them off, and a few leaves had turned brown.) Eight total plants. A couple of bulbs were good sized, one small and the rest medium. When I first dug them out, the individual cloves were hard to see. I thought it was one big clove. But now that they have been curing for a week or so, I can see the individual cloves. Maybe something like that will happen to you, or maybe that is even normal for full term garlic. Like I said, this was my first year.

--McKenzie

I have edited this post so no one will be led astray. Thanks for correcting my grave error,

This post was edited by still_kris on Wed, Jun 19, 13 at 9:13

Stillkris, while it's nice to leave advice here, it should be about something you know. People reading this in the future will think they should leave the flowers on their elephant garlic and what will they get? Smaller heads.

As I said, from my experience growing a lot of elephant garlic for sale is that every once in a while it just doesn't divide. If it's something other than genetics, I can't say.

-Mark

Thanks Mark...my other garlics did so well, I just thought I had done something wrong with the elephant. I should post a picture too