Help ID this giant plant.
Can someone tell me what this is?
I am a Cali native new to midwest gardening and found this plant growing in my new yard and I've never seen it before. The plant grows amazingly fast. I first spotted it about 3 weeks ago when it was ankle high. Its now taller than me. The leaves are over 8 inches long and it has a bunch of white flowers starting to form on the stem tops.