tazettas

Friends,
Some years ago, I received tazetta seeds from Bill Welch.  After some years in a pot, the little seedlings were planted in the open two years ago.  I figured if they were going to live in Ohio, they had to tough it out.  :-)
This year, two of them bloomed. (photo of one attached)   BUT . . .they are near miniature in size, maybe 6-7 inches tall.  I expected them to be standard size flowers.  I have another tazetta, collected in France several years ago, that blooms beautifully in a pot.  Last  year I planted 2 bulbs in the open.  One bloomed this spring, and it was maybe 1/4 to 1/3 the size of the bloom of the one in the pot.  Other bulbs in this bed grow “normally.”  Does anyone have any explanation for this?
Mary Lou