This is growing in my flowerbed where I planted "wildflower mix" seeds.
Looks a lot like a turnip...
I definitely wasn't expecting a turnip..
Um.. do turnips flower? How will I be able to know if it is indeed a turnip without pulling it up??
All plants flower. Wait until it flowers, the flower is usually a dead giveaway to ID.
It's possible it just looks a lot like it. I'm growing them in my garden and they look just like that.
Once it gets too hot a turnip will bolt. It's a brassica, flowers I believe are yellow or white.
Here is a link that might be useful: Turnip images
It could be Sinapis arvensis, Sinapis alba or some similar wild mustard. Also Brassicas. The flowers will tell.