Never Noticed.

       After a lifetime of Tradescantias as decorative, indoor, foliage plants; it came as a severe shock, a very few years ago, to find this was also a Tradescantia.
       What I must keep an eye out for?  On one hand, these decorative "Onions" (Can't remember if they're still Alliums) Hang to flower; then stand to attention to set seed.  You can see the ones on the left, here, starting to reach up; compared to the others.  The "other hand"? Yet to be established.
       "I'll tell you what I don't know" (One of my war-cries) I don't know if the Tradescantias reach up to flower while all the Buds stay down - OR - if they stay up after flowering like the Onions.