Are your alliums in full sun? Shade can make the stems weak.

Here is a link that might be useful: Doug Green

I have tried these things everywhere. They are in bright blazing sun by a concrete driveway, in my bed that gets at least 6 hours of direct sun and in my east bed that has really nice soil and gets sun until around 1:00 everyday and all my other plants love it! I just dug some up for my sister and on examination I'm wondering if it is just the way they grow because the stalk is very hefty. Thanks for replying though!

Some varieties of native alliums "nod", so there may be nothing wrong with yours. If it is in full sun I wouldn't worry about it too much.

Here is a link that might be useful: Nodding onion