Is it a fairly tall plant or is it low to the ground? If it's taller, it kind of looks like the horribly invasive wild mustard that grows everywhere in fields, etc. Sort of pretty until you realize how it's taken over lots of areas and is very hard to get rid of.
Next time you're near a field, take a look at all the yellow stuff that's growing everywhere and see if you think yours is the same. The mustard stuff is everywhere and it's blooming now, so you shouldn't have too much trouble finding some for comparison.