Anyone know what this plant is? I am in usda zone 9b
You'll find them sold as bacopa, a trailing plant usd in many planters. It's not the real bacopa (Bacopa genus plants) but Chaenostoma cordatum (synonym Sutera cordata).
You can see a photo and read how to care for it (very easy care!) at Bacopa Plant Info: How To Grow A Bacopa Plant It's treated like an annual but actually it's a tender perennial. It might even be winter hardy in your zone 9b if it's planted in the ground (but not if it's in a planter).
Interestingly I don't think I planted it. Just showed up in my pot. Good to know it's not invasive or a weed.– JStorageJul 2, 2017 at 2:33
I think it bears saying again that a weed is just a plant out of place. Grins. Common 'weeds' are usually plants that have either adapted so well at propagating themselves, have a wide range of tolerances or they were imported into a perfect habitat with no controls. Purple Loosestrife is an ornamental that was brought over because it was pretty. Loved the wetlands and each flower put out a million seeds well, something like that. Bocapa has become one of the most desired plants for pots this last decade or two. In zone 9 it could become an invasive weed, must be nice J.!! Love that guy– stormyJul 2, 2017 at 16:10